Ethylene copolymer

Abstract

The present invention relates to an ethylene-copolymer, wherein the ethylene copolymer comprises - units derived from ethylene as monomeric units; - units derived from one or more non-conjugated dienes as monomeric units in an amount higher than 2wt%, referred to the whole polymer composition being 100%; and - units derived from propylene as monomeric units wherein the ethylene-copolymer has a Mooney viscosity ML(1+4)125°C of ≥ 35, and wherein the ethylene copolymer has a relation between the parameters MWD and Δδ following or being above thew formula : ∆ ≥ 0.0208.×()°.

Description

[0001] Ethylene Copolymer

[0002] Ethylene Copolymer rubbers are widely known in the art and may be used for a plurality of applications. For example, ethylene-propylene-diene rubbers (EPDM) are widely used for rubber compounds in mixture with fillers and various ingredients to prepare several manufacts, such as sealing systems and hoses. Processing behavior of said compounds is of paramount importance and it is, to a large extent, determined by the EPDM structure within the mixture.

[0003] Frequently, ethylene-copolymers that result in compound with excellent mechanical properties (for instance tensile strength and compression sets), lead to compounds that are either difficult to mix or require too intensive processes, with the detrimental creation of off-spec material and / or high production costs.

[0004] Several approaches are attempted to overcome the poor processing behavior of high-performance EPDM. Without being bound to theory, some of the mostly employed methods rely on the use of blends of different EPDM polymers. Said blends can either be achieved via mixing different bales in the compounding production or produced in situ, i.e. during the polymerisation step, with several methods working on reactor cement blending or use of catalyst mixtures during the polymerisation step. Said approaches might be either uneconomical or complicated for commercially relevant practices, therefore modification of the polymer structure is also sought, in the measure of introducing long chain branching or perform post-polymerisation modifications.

[0005] WO 2020 / 069364 A1 describes a process of synthesizing long-chain branched ethylenebased polymers via the specific combination of a multi-chain catalyst and classes of dienes to induce long chain branching.

[0006] WO 2020 / 205585 A1 describes polymers comprising the polymerized product of ethylene, at least one diene comonomer, and optionally at least one C3 to C14 comonomer. The polymer comprises tri -functional long-chain branches resulting from the diene that occur at a frequency of at least 0.03 per 1000 carbon atoms of the polymer. Said processes lean on specific catalyst and reagent compositions, with may lead to complicated polymerisation processes.

[0007] Broad or bimodal EPDM polymers can be produced via catalyst mixtures, as depicted byWO2021185737 and W02020058267, although the use of different catalyst systems impairs a lean the polymerisation process, whilst interactions between the catalyst centers during polymerisation cannot be excluded.

[0008] Rubber processing can be improved via post-polymerisation processes, even at the cement level, thus involving the reactivity of the polymer chains with external reagents, with the obvious advantage of not influencing the delicate synthetic process of the polymer. WO2020 / 263681 A1 discloses a process including providing a neat ethylene / propylene / non-conjugated polyene terpolymer (n-terpolymer) having a Mooney viscosity (ML (1 +4) at 125°C) of less than 100 Mooney units (MU). The process includes exposing the n-terpolymer to electron beam radiation at a dosage from 0.2 megaRad (MRad) to 1.3 MRad. The process includes forming a branched ethylene / propylene / non-conjugated polyene terpolymer (b-terpolymer) having a Mooney viscosity ML (1+4) at 125°C of from 25 MU to 135 MU, however the process requires the access to specific machinery with additional operational burdens towards the final polymer production and no control of the polymer MWD is performed.

[0009] WO 2022 / 115410 A1 discloses a process including providing an ethylene / propylene / non-conjugated polyene terpolymer (EPDM) having at least 3.5 wt% non-conjugated polyene. The process includes reacting the EPDM with a metal-Lewis acid and forming a rheology-modified EPDM; however the use of a metallic Lewis acid implies partial crosslinking of the material with risk of forming gelled structures.

[0010] GB 4,157,398 discloses elastomers being described as having improved working properties and cold compression set and a process for preparing them. According to this document, a sulphur curable elastomer is reacted in bulk with a sulphur mono- or di-halide in which the halogen is chlorine or bromine, in an amount sufficient to reduce its cold compression set by at least 10% without substantially changing its sulphur curability or gelling a significant portion of the polymer.

[0011] In order to form respective articles from ethylene-based polymers, such as ethylene propylene-based polymers, the processing behavior is an important feature to support and broaden the possible applications. With this regard, there is still potential for improving the processability, especially within an extruder, of ethylene-based polymers.Summary

[0012] In one aspect, the present invention provides an ethylene-copolymer, wherein the ethylene copolymer comprises

[0013] - units derived from ethylene as monomeric units;

[0014] - units derived from one or more non-conjugated dienes as monomeric units in an amount higher than 2wt%, referred to the whole polymer composition being 100%; and

[0015] -units derived from propylene as monomeric units

[0016] wherein

[0017] the ethylene-copolymer has a Mooney viscosity ML(1+4)125°C higher than 35 Mooney units, and wherein the ratio between the polymer molecular weight distribution and branching level, expressed as difference between the phase angle 5 measured at 0.1 and 100 rad / s, follows the formula 1:

[0018] - > 0.0208eO O758><m(1).

[0019]

[0020] According to a further aspect, a method for producing an ethylene-copolymer like defined is provided, the method comprising the steps of:

[0021] i) Providing an intermediate ethylene-copolymer by copolymerizing at least ethylene, one or more non-conjugated dienes, and propylene as monomeric units;

[0022] ii) admixing the intermediate ethylene-copolymer with at least one viscosity increasing modification reagent; and

[0023] iii) forming the ethylene-copolymer by reacting the intermediate ethylene-copolymer with the at least one viscosity increasing modification reagent, wherein this step iii) is formed such, that the ethylene copolymer is dissolved, in particular fully dissolved, in a solvent or in other word, this step is performed in solution.

[0024] According to a still further aspect, the present invention provides an article formed from an ethylene copolymer as described before.

[0025] The present invention provides significant advantages over solutions of the prior art.

[0026] In particular, the present invention provides ethylene copolymers and methods of producing the same, wherein the ethylene copolymers show a broad molecular weight distribution (MWD) and branching with improved processing at given physical properties. As such, the polymers are produced via a technology allowing a post-polymerization adaption of the molecular weight and the Mooney viscosity; As a result, improvements in extruded strip quality, as well as processing performances, such as particularly low energy consumption, and high extrusion productivity are achieved. Within this, no appreciable deterioration to the physical properties of the vulcanizate are obtained.Detailed Description

[0027] In the following description norms may be used. If not indicated otherwise, the norms are used in the version that was in force on March 20, 2025. If no version was in force at that date because, for example, the norm has expired, then the version is referred to that was in force at a date that is closest to March 20, 2025.

[0028] In the following description the amounts of ingredients of a composition or polymer may be indicated interchangeably by “weight percent”, “wt. %” or “% by weight”. The terms “weight percent”, “wt. %” or “% by weight” are used interchangeably and are based on the total weight of the composition or polymer, respectively, which is 100 % unless indicated otherwise.

[0029] The term “phr” means parts by weight per hundred parts by weight of rubber.

[0030] Ranges identified in this disclosure include and disclose all values between the endpoints of the range and also include the end points unless stated otherwise.

[0031] The present invention provides an ethylene-copolymer, wherein the ethylene copolymer comprises

[0032] - units derived from ethylene as monomeric units;

[0033] - units derived from one or more non-conjugated dienes as monomeric units in an amount higher than 2wt%, referred to the whole polymer composition being 100%; and

[0034] -units derived from propylene as monomeric units

[0035] wherein

[0036] the ethylene-copolymer has a Mooney viscosity ML(1+4)125°C higher than 35 Mooney units, and wherein

[0037] the ratio between the polymer molecular weight distribution and branching level, expressed as difference between the phase angle 5 measured at 0.1 and 100 rad / s, follows the formula 1:

[0038] - > 0.0208e

[0039]

[0040] O O758><m(1).

[0041] AS—'

[0042] Provided is thus an ethylene-copolymer. Such a copolymer is generally known per se and is a copolymer of ethylene, propylene, one or more non-conjugated dienes, and, optionally, at least one further comonomer.The copolymer comprises units derived from one or more non-conjugated dienes as monomeric units in an amount higher than 2 wt%, referred to the whole polymer composition being 100%. It may further comprise from 40 wt% to 75 wt%, based on the weight of the polymer, of units derived from ethylene. In one embodiment of the present disclosure, the copolymer comprises from 41 wt% to 61 wt% or from 49 wt% to 59 wt% of units derived from ethylene. In one embodiment of the present disclosure, the copolymer comprises up to 56 % by weight or up to 52 % by weight of units derived from ethylene. In one embodiment the copolymer of the present disclosure comprises from 52% to 70% by weight or from 54% to 65% by weight, or from 57% to 68% by weight of units derived from ethylene.

[0043] Preferably, the ethylene-propylene copolymer contains at least 14 % by weight of units derived from propylene.

[0044] Non-conjugated dienes are polyenes comprising at least two double bonds, the double bonds being non-conjugated in chains, rings, ring systems or combinations thereof. The polyenes may have endocyclic and / or exocyclic double bonds and may have no, the same or different types of substituents. The double bonds are at least separated by two carbon atoms. The non-conjugated dienes are preferably aliphatic, more preferably alicyclic and aliphatic. Suitable non-conjugated dienes include aromatic polyenes, aliphatic polyenes and alicyclic polyenes, preferably polyenes with 6 to 30 carbon atoms (Ce-Cao-polyenes, more preferably Ce-Cao-dienes). Specific examples of non-conjugated dienes include 1,4-hexadiene, 3-methyl-1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 4-ethyl-1,4-hexadiene, 3,3-dimethyl-1,4-hexadiene, 5-methyl-1,4-heptadiene, 5-ethyl-1,4-heptadiene, 5-methyl-1,5-heptadiene, 6-methyl-1,5-heptadiene, 5-ethyl-1,5-heptadiene, 1 ,6-octadiene, 4-methyl-1,4-octadiene, 5-methyl-1 ,4-octadiene, 4-ethyl-1,4-octadiene, 5-ethyl-1,4-octadiene, 5-methyl-1,5-octadiene, 6-methyl-1,5-octadiene, 5-ethyl-1,5-octadiene, 6-ethyl-1,5-octadiene, 1,6-octadiene, 6-methyl-1,6-octadiene, 7-methyl-1,6-octadiene, 6-ethyl-1,6-octadiene, 6-propyl-1,6-octadiene, 6-butyl-1,6-octadiene, 4-methyl-1,4-nonadiene, 5-methyl-1,4-nonadiene, 4-ethyl-1,4-nonadiene, 5-ethyl-1,4-nonadiene, 5-methyl-1,5-nonadiene, 6-methyl-1,5-nonadiene, 5-ethyl-1,5-nonadiene, 6-ethyl-1,5-nonadiene, 6-methyl-1,6-nonadiene, 7-methyl-1,6-nonadiene, 6-ethyl-1,6-nonadiene, 7-ethyl-1,6-nonadiene, 7-methyl-1,7-nonadiene, 8-methyl-1,7-nonadiene, 7-ethyl-1,7-nonadiene, 5-methyl-1,4-decadiene, 5-ethyl-1,4-decadiene, 5-methyl-1,5-decadiene, 6-methyl-1,5-decadiene, 5-ethyl-1,5-decadiene, 6-ethyl-1,5-decadiene, 6-methyl-1,6-decadiene, 6-ethyl-1,6-decadiene, 7-methyl-1,6-decadiene, 7-ethyl-1,6-decadiene, 7-methyl-1,7-decadiene, 8-methyl-1,7-decadiene, 7-ethyl-1,7-decadiene, 8-ethyl-1,7-decadiene, 8-methyl-1,8-decadiene, 9-methyl-1,8-decadiene, 8-ethyl-1,8-decadiene, 1 ,5,9-decatriene, 6-methyl-1 ,6-undecadiene, 9-methyl-1 ,8-undecadiene, dicyclopentadiene, and combinations thereof.

[0045] Further examples of non-conjugated dienes include dual polymerizable dienes. Dual polymerizable dienes include vinyl substituted aliphatic monocyclic and non-conjugated dienes, vinyl substituted bicyclic and unconjugated aliphatic dienes, alpha-omega nonconjugated dienes. Dual polymerizable dienes may cause or contribute to the formation of polymer branching. Specific examples include 1,4-divinylcyclohexane, 1,3-divinylcyclohexane, 1,3-divinylcyclopentane, 1,5-divinylcyclooctane, 1 -allyl-4-vinylcyclo-hexane, 1,4 diallyl cyclohexane, 1-allyl-5-vinylcyclooctane, 1,5-diallylcyclooctane, 1-allyl-4-isopropenyl-cyclohexane, 1-isopropenyl-4-vinylcyclohexane and 1-isopropenyl-3-vinylcyclopentane, dicyclopentadiene and 1 ,4-cyclohexadiene. Preferred are nonconjugated vinyl norbornenes and C8-C12 alpha omega linear dienes. The dual polymerizable dienes may be further substituted with at least one group comprising a heteroatom of group 13-17 for example O, S, N, P, Cl, F, I, Br, or combinations thereof. Examples of aromatic non-conjugated polyenes include vinylbenzene (including its isomers) and vinyl-isopropenyl benzene (including its isomers).

[0046] Preferred non-conjugated dienes include alicyclic polyenes. Alicyclic dienes have at least one cyclic unit. In a preferred embodiment the non-conjugated dienes are selected from polyenes having at least one endocyclic double bond and optionally at least one exocyclic double bond.

[0047] Preferred examples include dicyclopentadiene (DCPD), 2,5-norbornene, 5-vinyl-2-norbornene (VNB), 1,7-octadiene, 1,9-decadiene, 5-vinyl-2-norbornene (VNB) 5-methylene-2-norbornene (MNB) and 5-ethylidene-2-norbornene (ENB) and combinations thereof. Even more preferred examples include 5-methylene-2-norbornene (MNB), 5-ethylidene-2-norbornene (ENB), 5-vinyl-2-norbornene (VNB), dicyclopentadiene (DCPD).

[0048] 1 ,4-hexadiene and combinations thereof.

[0049] In one embodiment the copolymer of the present disclosure comprises or contains only 5-methylene-2-norbornene (MNB), 5-ethylidene-2-norbornene (ENB), 5-vinyl-2-norbornene (VNB), dicyclopentadiene (DCPD). 1,4-hexadiene ora combination thereof, such as ENB, VNB or DCPD or a combination thereof as non-conjugated diene.

[0050] In one embodiment the copolymer of the present disclosure contains only ENB as nonconjugated diene.In one embodiment the copolymer of the present disclosure contains only VNB as nonconjugated diene.

[0051] In one embodiment the copolymer of the present disclosure contains only DCPD as nonconjugated diene.

[0052] In one embodiment the copolymer of the present disclosure contains only ENB and VNB as non-conjugated diene.

[0053] In a typical embodiment of the present disclosure the copolymer contains at least 3 wt. % and up to and including 20 wt. % of units derived from non-conjugated diene. In another preferred embodiment, the copolymer contains from 2 to 18 wt. % of units derived from nonconjugated diene, more preferably from 5 to 18 wt. %, for example from 7 to 15 wt. %. In a preferred embodiment the copolymer contains from 3 wt. % and up to 20% wt. % of units derived from ENB, and, more preferably from 6 to 18 wt. % of units derived from ENB, from or from 7 to 17 wt. % of units derived from ENB (all wt.% based on the total weight of the copolymer). In one embodiment, the copolymer of the present disclosure contains from 0 wt. % to 5 wt. %, more preferably from 0.10 wt. % to 3 wt. %, or from 0.2 wt. % to 1.2 wt. % of units derived from VNB.

[0054] The ethylene-propylene copolymer according to the present disclosure may have an ENB content per polymer chain of at least 10 units, at least 20 units, or at least 30 units. In one embodiment of the present disclosure the ethylene copolymer according to the present disclosure has an ENB content per polymer chain of from about 25 up to about 70 units.

[0055] According to an embodiment, the ethylene-copolymer comprises

[0056] - 40 > wt.-% to < 75 wt.-% of units derived from ethylene as monomeric units;

[0057] - 3 > wt.-% to < 20 wt.-% of units derived from one or more non-conjugated dienes as monomeric units, wherein the one or more dienes comprise at least one of 5-ethylidene-2-norbornene (ENB) and 5-vinyl-2-norbornene (VNB), and dicyclopentadiene and 1,4-hexadiene; and

[0058] - at least 14 wt.-% of monomeric units derived from propylene.

[0059] In addition to units derived from ethylene and propylene and a non-conjugated diene, the copolymer according to the present disclosure, optionally, has repeating units derived from one or more further comonomers. Suitable further comonomers include C4-C2o-a-olefins.

[0060] C4-C2o-a-olefins (also referred to herein as” C4-C20 alpha olefins”) are olefins containing fromfour to twenty carbon atoms and having a single aliphatic carbon-carbon double bond. The double bond is located at the terminal front end (alpha-position) of the olefin. The a- olefins can be aromatic or aliphatic, linear, branched or cyclic. Examples include but are not limited to 1 -butene, 1 -pentene, 1 -hexene, 1 -heptene, 1 -octene, 1 -nonene, 1 -decene, 1 -undecene, 1 -dodecene, 1 -tridecene, 1 -tetradecene, 1 -pentadecene, 1 -hexadecene, 1-hepta-decene, 1 -octadecene, 1 -nonadecene, 1-eicosene, 3-methyl-1 -butene, 3-methyl-1 -pentene, 3-ethyl-1 -pentene, 4-methyl-1 -pentene, 4-methyl-1 -hexene, 4, 4-dimethyl-1 -hexene, 4,4-dimethyl-

[0061] 1-pentene, 4-ethyl-1 -hexene, 3-ethyl-1 -hexene, 9-methyl-1 -decene, 11-methyl-1 -dodecene and 12-ethyl-1 -tetradecene. The alpha olefins may be used in combination.

[0062] Further, due to a post-polymerization process in order to adapt the Mooney viscosity of the before-formed ethylene-based copolymer as described in greater detail with regard to the method, it may be allowed that the ethylene copolymers according to the present invention shows the following properties:

[0063] a Mooney viscosity ML(1+4)125°C of > 35, and

[0064] a relation between the parameters MWD and Ab of

[0065] MWD>n Q208eO O758xML(1+4^125°c

[0066]

[0067] M—■

[0068] Preferably, the ethylene-copolymer has a relation of MWD / b which is in a range of > 0.32.

[0069] The ethylene-propylene copolymers according to the present disclosure have a high Mooney viscosity ML(1+4)125°C of > 35 Mooney units (MU), preferably at least 37 Mooney units. The copolymers may have Mooney viscosities up to 200 Mooney units or above 200 Mooney units, which means the Mooney viscosity cannot be measured anymore.

[0070] Preferably, the ethylene copolymers according to the present disclosure are branched, for example with a branching level A3 of < 8.2, such as between 0.3 and 8.2 degrees, more preferably with a A3 between 0.3 and 7.5 degrees.

[0071] The ethylene-propylene copolymers according to the present disclosure preferably have a weight average molecular weight (Mw) of at least 100,000 g / mol and up to 1 ,000.000 g / mol. In one embodiment the copolymers have an Mw of at least 180,000 g / mol and more preferably at least 200,000 g / mol. In one embodiment of the present disclosure the number-averaged molecular weight (Mn) of the ethylene-copolymers may be from about 25 to 500 kg / mol, or from 40 to 230 kg / mol. The ethylene copolymer of the present disclosure preferably may have a molecular weight distribution (Mw / Mn, MWD), of at least 2.0, forexample from 2.3 to 10.0 or from 3.4 to 7.

[0072] Preferably, the ethylene copolymer according to the present invention has a Mooney stressrelaxation rate of < 0.54, such as of < 0.50, preferably < 0.48, as measured in logMU / logs.

[0073] Such an ethylene copolymer may be produced by the following method, which comprises the steps of:

[0074] i) Providing an intermediate ethylene-copolymer by copolymerizing at least ethylene, one or more non-conjugated dienes, and propylene as monomeric units;

[0075] ii) admixing the intermediate ethylene-copolymer with at least one viscosity increasing modification reagent; and

[0076] iii) forming the ethylene-copolymer by reacting the intermediate ethylene-copolymer with the at least one viscosity increasing modification reagent, wherein this step iii) is formed such, that the ethylene copolymer is dissolved in a solvent.

[0077] The method according to the invention thus is directed towards firstly preparing an ethylene copolymer according to standard polymerization techniques, also called an intermediate copolymer in the sense of the present invention. This may be performed as follows in a manner as known per se.

[0078] The copolymers according to the present disclosure can be prepared by a process comprising copolymerizing ethylene, propylene, a non-conjugated diene and, optionally, at least one further comonomer as known in the art of producing ethylene-copolymers. The polymers may be produced by using conventional catalysts, like for example Ziegler-Natta-catalysts or metallocene-type catalysts or a combination of catalysts. Ziegler-Natta catalysts are non-metallocene type catalysts based on halides of transition metals, in particular titanium or vanadium. Metallocene-type catalysts are organometallic catalysts wherein the metal is bonded to at least one cyclic organic ligand, preferably at least one cyclopentadienyl or at least one indenyl ligand. In one embodiment a Ziegler-Natta catalyst is used. In another embodiment, preferably a metallocene-type catalyst is used. In another embodiment a combination of two or more metallocene-type catalysts is used.

[0079] The polymerization can be carried out in the gas phase, in a slurry, or in solution in an inert solvent, preferably a hydrocarbon solvent. The polymerization may be carried out continuously, for example in one or more continuously stirred tank reactors, one or more loop rectors, or as a batch reaction in one or more batch reactors or a combination thereof.The continuous reaction may be carried out adiabatically or non-adiabatically. Multiple reactors may be used and may be connected in series or in parallel. Solvents and monomers may be chilled prior to entering the reaction for temperature control. Monomers may be evaporated for temperature control.

[0080] Preferably, the polymerization is carried out as solution polymerization, namely where all the reactants and the products are dissolved in a solvent medium. Preferred solvents include one or more hydrocarbon solvent. Suitable solvents include C5-12 hydrocarbons such as pentane, hexane, heptane, octane, cyclohexane, methylcyclohexane, pentamethyl heptane, hydrogenated naphtha, isomers and mixtures thereof. The polymerization may be conducted at temperatures from 10 to 250 °C, depending on the product being made. Most preferably the polymerisation is performed at temperatures greater than 50 °C, if performed in solution.

[0081] In a preferred embodiment the polymerization includes the use of one or more chain transfer agent to control the molecular weight of the polymer. A preferred chain transfer agent includes hydrogen (H2). The diene content per polymer chain can be controlled, for example, by controlling the amount of dienes in the reaction and the molecular weight (chain length) as known in the art. Branching can be introduced as known in the art, for example by using specific catalysts, for example vinyl group creating catalysts, or by using monomers that create polymer branching, for example dual polymerizable dienes or by using a combination of both. The degree of branching can be controlled, for example, by adjusting their amounts or feed streams during the polymerization as is known in the art.

[0082] Afterwards and according to step ii), the intermediate ethylene-copolymer is admixed with at least one viscosity increasing modification reagent; and the ethylene-copolymer is correspondingly formed by reacting the intermediate ethylene-copolymer with the at least one viscosity increasing modification reagent according to step iii).

[0083] Surprisingly, it has been found that it is possible to treat the ethylene propylene-based polymer, i.e. the intermediate polymer, with at least one viscosity increasing modification reagent leading to a significant increase in molecular weight of the before-formed polymer and thus increases the Mooney viscosity by increasing the degree of branching.

[0084] In particular, it was found that forming the ethylene-copolymer by reacting the intermediate ethylene-copolymer with the at least one viscosity increasing modification reagent such,that the ethylene copolymer is dissolved in a solvent, significant advantages over the respective reaction in bulk can be seen. In fact, whereas according to the prior art the reaction in bulk leads to a decrease of cold compression set by at least 10%, the cold compression set according to the present invention is maintained essentially the same. This shows that the influence of the reaction of the viscosity increasing modification reagent with the polymer is different when being performed in bulk compared to a rection in solution. Accordingly, the provided polymers also differ. Therefore, especially in case the reaction is performed in solution, the advantages as described apply. Suitable solvents comprise hexane, such as anhydrous hexane and in general every solvent which is suitable for dissolving the polymer.

[0085] Preferably, the polymerizate is modified to branch the polymer by means of sulphur bridge bonding by a post-polymerization process. Surprisingly, a respective adaption of the molecular weight and thus of the Mooney value is well possible for ethylene propylene copolymers and in a very advantageous manner fulfills the objects of the present invention.

[0086] The at least one viscosity increasing modification reagent preferably comprises a sulphur halogenide containing compound. For example, the viscosity increasing modification reagent consists of one or more sulphur halogenides. Examples for sulphur halogenides comprise sulphur bromide or sulphur chloride, wherein sulphur chlorides may be preferred. Preferably, disulphur dichloride, sulphur dichloride, sulphur bromide, sulphur dichloride, thionyl chloride, disulphur dibromide or thionyl bromide are used for the modification. Treatment is preferably affected with disulphur dichloride.

[0087] In general, 0.05 to 0.7 parts by weight, preferably 0.1 to 0.4 parts by weight, of viscosity increasing modification reagent, such as of sulphur bromides or suphur chlorides, are added to 100 parts by weight of ethylene propylene based polymer, i.e. the intermediate ethylenecopolymer.

[0088] The treatment of the ethylene-based polymer with the viscosity increasing modification reagent may be effected at temperatures of 20°C to 150°C, preferably of > 70°C.

[0089] The treatment of the ethylene-based polymer with the viscosity increasing modification reagent may be effected for a duration of > 1 hour, preferably for a duration of > 2 hours, such as for a duration of > 4 hours.In the process according to the invention, the aforementioned viscosity increasing modification reagent is stirred with the intermediate ethylene-copolymer for about more than 1 hour, preferably at temperatures of 20°C to 150°C. Thereafter the reaction mixture is worked up by stripping off the solvent with steam in the usual manner and the product may be dried, e.g. by using a strainer screw and a downstream hot air drier.

[0090] Thus, the ethylene copolymer according to the present invention may be by means of a post-polymerization step in order to adapt the Mooney viscosity, leading to the advantages as outlined with regard to the polymer as such.

[0091] The present invention further relates to an article formed from an ethylene copolymer as described above and correspondingly by a method as described above. Non limiting preferred examples of such articles especially comprise extruded articles and, in more detail, may comprise inter alia hoses and sealings systems.

[0092] Such articles show the advantage of an improved manufacturing process as the ethylene propylene copolymers from which these articles are formed show an improved processability.In the forthcoming section the measurement methods for the polymer parameters are reported.

[0093]

[0094] and stress-relaxation rate.

[0095] The Mooney viscosity was measured as ML(1+4)125°C in Mooney Units (MU) according to ISO 289-1 orASTM D 1646.

[0096] The Mooney stress-relaxation rate (MSR) is measured in (logMU / logs) according to ISO 289.

[0097] Comonomer composition

[0098] Fourier transformation infrared spectroscopy (FT-IR) was used to determine the composition of the copolymers according to ASTM D3900 (revision date 2017) for the C2 / C3 ratio and D6047 (revision date 2017) for the diene content on pressed polymer films.

[0099] Phase angle measurements

[0100] The polymer branching was determined by phase angle measurements on a Montech MDR 3000 moving die rheometer, using the parameter A3. The A3 parameter (expressed in degrees) is the difference between the phase angle 8 measured at a frequency of 0.1 rad / s and the phase angle 8 measured at a frequency of 100 rad / s determined by Dynamic Mechanical Analysis (DMA) at 125 °C. The parameter has been introduced by H.C. Booij, in Kautschuk + Gummi Kunststoffe, Vol. 44, No. 2, pages 128-130,1991, which is incorporated herein by reference. The lower the value of A8 the more chain branches are present in the polymer.

[0101] Size exclusion chromatography with differential viscometry (SEC-DV)

[0102] The molecular weight distribution (MWD) and momenta (Mn, Mw, Mz) were determined by gel permeation size exclusion chromatography with differential viscometry (GPC / SEC-DV) using an IR detector. The Size Exclusion Chromatograph was equipped with an online viscometer, an online infrared detector (IR5 MCT), with 3 AGILENT PL OLEXIS columns (7.5 x 300 mm) and a Polymer Char autosampler. Universal calibration of the system was performed with polyethylene (PE) standards. The polymer samples were weighed (in the concentration range of 0.3-1.3 mg / ml) into the vials of the PolymerChar autosampler. In the autosampler the vials were filled automatically with solvent (1,2,4-tri-chlorobenzene) stabilized with 1 g / l di-tertbutylparacresol (DBPC). The samples were kept in the hightemperature oven (160°C) for 4 hrs. After this dissolution time, the samples were automatically filtered by an in-line filter before being injected onto the columns. The chromatograph system was operated at 160°C. The flow rate of the 1,2,4-trichlorobenzene eluent was 1.0 mL / min. The chromatograph contained a built-in on-line infrared detector (IR5 MCT) for concentration and a built-in PolymerChar on-line viscometer.

[0103] In order to produce the inventive examples, commercially available comparative example 1 (Cp1) was subjected to a modification by reacting the latter with disulphur dichloride (S2CI2) as coupling agent, also named viscosity increasing modification reagent, according to the procedure here described. 8400 g of dry comparative example 1 polymer was dissolved in anhydrous hexane under agitation in an inert atmosphere (N2) to form a 16wt% solution. The solution was heated to 90°C. The main characteristics of comparative example 1 are described below in table 1 and reported for completeness in this text.

[0104] Mooney viscosity (ISO 289-1) as per ML(1+4)125°C = 32 MU.

[0105] Ethylene content (ASTMD3900) as per C2 = 48.8 wt%.

[0106] ENB content ASTMD6047 as per ENB = 7.7 wt%.

[0107] Subsequently, the coupling agent, also called viscosity increasing modification reagent, was added slowly over 45 min (0.40 phr; phr: weight parts per hundred rubber) and stirred at 90°C. Aliquots of solutions were taken after 5, 10 and 20 hours, stabilized with Irganox 1076 and steam stripped to produce the inventive polymers according to inventive examples Ex1, Ex2, Ex3. The obtained polymers have been characterized according to the method described in the experimental section and results are reported in table 1.

[0108] The comparative examples (Cp1, Cp2, Cp3) are made by polymers with a similar composition and Mooney level than the inventive ones, although prepared via a solution polymerisation process, without the use of coupling agent.Table 1. Molecular characterisation results of inventive and comparative polymers.

[0109] Units Ex. 1 Ex. 2 Ex. 3 Cp1 Cp2 Cp3

[0110] S2CI2, phr 0.40 0.40 0.40 - - - Modification h 5 10 20 - - - Time

[0111] ML(1+4)125°C MU 37 54 80 32 45 78

[0112] MSR logMU / logs 0.477 0.389 0.338 0.550 0.600 0.648

[0113] Ab 6.9 3.1 0.4 8.3 17 22

[0114] C2 wt% 44.5 44.6 44.6 48.8 52.3 48.5

[0115] ENB wt% 7.6 7.7 7.6 7.7 4.3 4.9

[0116] VNB wt% 0.52 0.52 0.52 0.50 0.09 0.20

[0117] Mn Kg / mol 57 59 60 50 60 95

[0118] Mw Kg / mol 205 245 310 180 180 300

[0119] Mz Kg / mol 730 950 1200 650 430 900

[0120] MWD - 3.6 4.2 5.2 3.6 3.1 3.2

[0121] ENB / Chain mol 36 38 38 36 22 40

[0122] MWD / Ab 0-1 0.52 1.35 13.00 0.43 0.18 0.15

[0123]

[0124] It can be seen that the modification, i.e. the reaction with the viscosity increasing modification reagent, produces broad MWD EPDM polymers with increased level of branching, as seen by a lower value of Ab parameter, like shown in detail below. It can especially be seen, that the molecular weight is significantly increased and correspondingly the Mooney viscosity is significantly increased. Further, the Ab is significantly lower.

[0125] With regard to the molecular weight distribution, it can be seen that this is changed in dependence from the duration of the modification. This shows that the process is highly adaptable and thus the formed modified polymers can be tailored to the respective application.

[0126] According to the parameters as outlined in table 1, said inventive polymers differ from their comparative counterparts by the relation between the parameters MWD and Ab, which, according to the present invention, lies according to the invention in a range of

[0127] MWD>n Q208eO O758xML(1+4^125°c

[0128]

[0129] M—■

[0130] This can be visualized by the curve as shown in figure 1. According to the present invention, all values lying on or above the curve are inventive examples and thus show the inventive effect. From the data above, it is possible to see that the inventive polymers lie all within a correlation curve between the polymer Mooney viscosity and the ratio between their polydispersity index (MWD) over their branching parameter (Ab).As will be shown below, the polymers according to the present invention provide improvements in extruded strip quality, as well as processing performances, such as lower energy consumption and higher extrusion productivity, with no appreciable deterioration to the physical properties of the vulcanisate.

[0131] The polymers of table 1 have been evaluated in compound testing against their commercial counterparts for a critical compound study, according to recipe of table 2.

[0132] Table 2 shows a critical model compound recipe employed for the present invention, total loading 217.3 phr, sulphur curing.

[0133] Table 2. Critical model compound recipe, sulphur cured.

[0134] Ingredient description Amount, phr EPDM Ethylene-propylene-diene tertpolymer 100

[0135] RU CORAX N 550 Carbon black N550 grade 60 PALMERA A9818 Stearic Acid 1 RHENOGRAN CAO 80 Calcium oxide, 80%wt 5 RHENOGRAN S-80 Sulphur, 80% wt 1.3 ZINKOXYD AKTIV Zinc oxide 5

[0136] PLI PROCESS OIL P 460 Process oil 39 RHENOGRAN MBTS-80 Dibenzothiazole disulfice, 80%wt 1.3 RHENOGRAN TP-50 Zinc dialkyldithiophosphate, 50%wt 3.5 RHENOGRAN ZBEC-70 Zinc dibenzyldithiocarbamate, 70%wt 0.7 VULKALENT E / C N-phenyl-n-(trichloromethylsulfenyl)-benzene 0.5

[0137] sulphonamide

[0138]

[0139] The polymers according to the invention and the comparative examples were used to make compounds using the ingredients listed in table 2. The compounds were prepared on an internal mixer(GK1,5 E1 from Harburg-FreudenbergerMaschinenbau GmbH; ram pressure 8 bar, 50 rpm, 72% degree of filling and total mixing time 5 min). The curing system was added, see table, on an open mill (200 mm roll diameter; 20 rpm, 40°C roll temperature and friction 1.22).

[0140] The vulcanisation parameters are measured via a moving die rheometer measurement done at 180°C, according to DIN53529. The AS value is defined as difference between themaximum and the minimum torque registered by the instrument (namely torque difference MH-ML at 180°C). The value of t90 is the time to reach 90 % of maximum torque during the moving die rheometer measurement.

[0141] The compounds as produced like described above were tested for their mechanical and elastic properties. For measurements of cured compounds, test plates were prepared from the compounds having 2 mm and 6 mm thickness, respectively, that were press cured at 180°C for a time equivalent to 1.1 and 1.25 times the t90 value, where t90 is the time to reach 90 % of maximum torque during the moving die rheometer measurement.

[0142] The Tear strength is measured in N according to ISO34-2.

[0143] The shore A hardness (Hardness) was determined according to DIN ISO 7629-1.

[0144] The tensile strength at break (Tensile strength, TS) and the elongation at break (EAB) were determined according to DIN ISO 37.

[0145] The compression set (OS) was determined according to DIN ISO 815.

[0146] The Rebound was measured ASTM D7121.

[0147] The compounds were tested according to the methods as outlined above and as described in the following table 3.

[0148] The physical properties and processing performance of compounds of table 2 are shown in table 3.

[0149] Further, profiles were extruded (from the unvulcanised compound) in a Brabender 19mm extruder through a Garvey profile (shown in figure 2, die diameter 4 mm,), according to the following settings, wherein for Ex.3 and CP3, two samples were produced each:

[0150] Housing I mould and screw temperature = 100°C and 80°C;

[0151] Measuring time = 60 seconds;

[0152] Roll speed = 50 rpm;

[0153] Nozzle diameter = 4 mm;

[0154] The processing performances are evaluated via the amount of extruded mass of compound, normalised by the pressure measured at the die. The higher is the value, themore efficient the extrusion is.

[0155] The quality of the profiles is evaluated on extruded strips, according to the rate system B of ASTM D2230.

[0156] Table 3. Performance results for the polymers of the invention, once compounded according to the recipe of table 2.

[0157] Measurement Unit Cp1 Ex. 1* Cp2 Ex. 2* Cp3 Ex. 3*

[0158] Compound Mooney MU 31 34 52 37 69 42

[0159] AS dNm 15.3 15.0 16.2 15.0 16.8 14.6

[0160] t90 min 2.8 3.0 4.4 4.5 4.2 4.3

[0161] Tear strength N 30 30 31 30 31 31

[0162] Hardness ShA 58 57 59 57 59 56

[0163] Tensile strength MPa 12 11 13 12 14 13

[0164] Elongation at Break % 488 448 542 453 457 451 Compression set % 42 44 48 46 40 41

[0165] 24h / 100°C

[0166] Compression set % 11 13 14 13 12 12

[0167] 24h / 70°C

[0168] Compression set % 6 6 6 5 6 5

[0169] 72h / 23°C

[0170] Rebound % 50 51 55 52 56 53

[0171] Ageing 168h - 100°C

[0172] Tear strength N 26 25 25 25 27 25

[0173] Hardness ShA 62 63 64 62 63 61

[0174] Tensile Stregnth MPa 10 9 10 10 13 10

[0175] Elongation at Break % 290 256 308 276 292 252

[0176] Processing performances

[0177] Mass / Pressure g / bar 1.1 1.6 0.8 1.5 0.6 0.9

[0178] (100°C)

[0179] Mass / Pressure (80°C) g / bar 1.2 1.3 0.5 0.8 0.4 0.8

[0180]

[0181] From table 3, it can be seen that the inventive examples have similar physical performance than the comparative examples, when the comparison is done at the same polymer Mooney level. With this regard, even though the Mass / Pressure value of the comparative examples may comeinto the range of the inventive examples, it is always required to compare examples which are in the same Mooney range in order to get comparable results.

[0182] The inventive examples, however, display a lower compound Mooney, and a higher ratio of extruded compound over pressure at the extruder nozzle, compared to the comparative examples. Said value correlates with the energy needed for extrusion: the higher is the ratio, the lower energy is needed to produce the extrudate.

[0183] Additionally, the improvement in processing performances translates in a higher quality of the extrudate profiles, as it can be seen in figure 2 for compounds of table 2. In said figure, the compounds made with the comparative examples display surface defects, whereas with the inventive examples, flawless profiles are obtained.

[0184] The inventive examples Ex1, Ex2 and Ex3 display similar physical and elastic properties than their comparative examples (Cp1, Cp2, Cp3), as seen in table 3.

Claims

Claims1. An ethylene-copolymer, wherein the ethylene copolymer comprises- units derived from ethylene as monomeric units;- units derived from one or more non-conjugated dienes as monomeric units in an amount higher than 2wt%, referred to the whole polymer composition being 100%; and- units derived from propylene as monomeric unitswhereinthe ethylene-copolymer has a Mooney viscosity ML(1+4)125°C higher than 35 Mooney units, and whereinthe ratio between the polymer molecular weight distribution and branching level, follows or is above the formula 1:— > 0.0208eO O758><m(1).

2. The ethylene-copolymer according to claim 1 , wherein the ethylene copolymer has a Ab value of < 8.2.

3. The ethylene-copolymer according to any of any of claims 1 or 2, wherein the ethylene copolymer has a Mooney stress-relaxation rate of < 0,54.

4. The ethylene-copolymer according to any of any of claims 1 to 3, wherein the ethylene copolymer has a molecular weight distribution of at least 2.0.

5. The ethylene-copolymer according to any of the preceding claims, wherein a relation of MWD / Ab is in a range of > 0.32.

6. The ethylene-copolymer according to any of any of the preceding claims, wherein the non-conjugated diene is selected from dicyclopentadiene, 2,5-norbornene, 5-vinyl-2- norbornene, 1,7-octadiene, 1,9-decadiene, 5-vinyl-2-norbornene 5-methylene-2- norbornene and 5-ethylidene-2-norbornene and combinations thereof.

7. The ethylene-copolymer of any one of the preceding claims wherein the ethylenecopolymer comprises- 40 > wt.-% to < 75 wt.-% of units derived from ethylene as monomeric units;- 3 > wt.-% to < 20 wt.-% of units derived from one or more non-conjugated dienes asmonomeric units, wherein the one or more dienes comprise at least one of 5-ethylidene- 2-norbornene (ENB) and 5-vinyl-2-norbornene (VNB), and dicyclopentadiene and 1,4- hexadiene; and- at least 14 % by weight of monomeric units derived from propylene.

8. A method for producing an ethylene-copolymer according to any one of claims 1 to 7, the method comprising the steps of:i) Providing an intermediate ethylene-copolymer by copolymerizing at least ethylene, one or more non-conjugated dienes, and propylene as monomeric units;ii) admixing the intermediate ethylene-copolymer with at least one viscosity increasing modification reagent; andiii) forming the ethylene-copolymer by reacting the intermediate ethylene-copolymer with the at least one viscosity increasing modification reagent, wherein this step iii) is formed such, that the ethylene copolymer is dissolved in a solvent.

9. The method according to claim 8, wherein the at least one viscosity increasing modification reagent comprises a sulphur halogenide.

10. The method according to claim 9, wherein the at least one sulphur halogenide is selected from the group consisting of disulphur dichloride, sulphur dichloride, and thionyl chloride.

11. The method of claim 8 to 10, wherein reacting the intermediate ethylene-copolymer with the at least one at least one viscosity increasing modification reagent according to step iii) is performed for > 2 hours at > 70°C.

12. An article formed from an ethylene copolymer according to any of claims 1 to 7.

13. The article according to claim 12, wherein the article is selected from a hose and a sealing.

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