Polyolefin polymers with low volatile content

Abstract

A method for providing an EPDM polymer having a reduced volatile ENB content, the method comprising (i) providing an EPDM polymer comprising from 1 to 20 % by weight of units derived from ENB, based on the total weight of the EPDM polymer, (ii) treating the EPDM polymer of step (i) with superheated steam to reduce the volatile ENB content of the EPDM polymer; (iii) stopping the treatment with superheated steam, (iv) optionally cooling the polymer to room temperature.

Description

Technical Field

[0001] This disclosure relates to a method for producing a polyolefin polymer with a low volatile content, and to the polymer produced by the method and its applications. Background Technology

[0002] Most commercial methods for producing polyolefins involve the removal of solvents and unused monomers, typically achieved through dry finishing or steam stripping. In the production of EPDM rubber, monomers with norbornene structures, such as ethylene norbornene (ENB) and vinyl norbornene (VNB), are frequently used to provide crosslinking or branching sites. These comonomers are difficult to remove completely by dry finishing or steam stripping, and they are foul-smelling even at very low concentrations. Therefore, there is a need for a method to provide polyolefin polymers with low norbornene content (such as ENB or VNB, or both). Summary of the Invention

[0003] Therefore, in one aspect, a method is provided for providing an EPDM polymer with a reduced volatile ENB content, the method comprising: (i) Provide an EPDM polymer comprising, by weight, 1% to 20% of ENB-derived units based on the total weight of the EPDM polymer. (ii) Treat the EPDM polymer of step (i) with superheated steam to reduce the volatile ENB content of the EPDM polymer; (iii) Stop using superheated steam treatment. (iv) Optionally, the polymer may be cooled to room temperature.

[0004] In another aspect, a polymer composition is provided comprising at least 95% by weight, or at least 99% by weight, of an EDPM polymer having 1% to 20% by weight of ENB-derived units and optionally 0.2% to 10% by weight of VNB-derived units, wherein the polymer composition has an ENB volatile content of less than 1.5 ppm, less than 0.95 ppm, or less than 0.60 ppm.

[0005] On the other hand, a method for manufacturing TPV is provided, the method comprising (i) extruding a blend produced by combining the polymer composition with a thermoplastic polymer, preferably a polypropylene polymer, and (ii) extruding the resulting mixture in the presence of at least one curing agent to produce TPV, wherein the blend is produced before or during the extrusion.

[0006] In another aspect, an article obtained using the polymer composition is provided. Attached Figure Description

[0007] Figure 1 A graph showing the temperature-pressure relationship and drying capacity of steam is presented. The upper solid line is the curve of steam temperature versus pressure. The lower solid line shows the temperature of superheated steam when the pressure drops from the corresponding pressure on the corresponding temperature-pressure curve to 1 bar. The dashed line shows the drying capacity of supersaturated steam. Detailed Implementation

[0008] In the following description, the terms “comprising,” “containing,” “including,” and “having” are used in an open sense and are not intended to exclude the presence of any additional components, steps, or procedures, whether or not such components, steps, or procedures are specifically disclosed. For example, the term “composition comprising components A and B” means that components other than A and B may also be present in the composition. The term “composed of” is used in a restrictive sense to exclude the presence of any additional components, steps, or procedures. For example, the term “composition composed of components A and B” means that components other than A and B are not present in the composition.

[0009] Specifications may be used in the following description. Unless otherwise specified, specifications refer to the version that became effective on March 1, 2020. If there is no version that became effective on that date, for example because the specification has expired, the version that became effective on the nearest date to March 1, 2020 shall be referenced.

[0010] In the following description, the amount of a component of the composition or polymer may be indicated by “weight percentage,” “wt.%” or “by weight %”. The terms “weight percentage,” “wt.%” or “by weight %” are used interchangeably and are based on the total weight of the composition or polymer as 100%, unless otherwise specified.

[0011] The term "phr" refers to the number of parts per hundred of rubber, which is the weight percentage of the total amount of rubber set at 100%.

[0012] Unless otherwise stated, the scope defined in this disclosure is intended to include and disclose all values ​​between the endpoints of the scope and to include the endpoints.

[0013] This disclosure provides a method for reducing the volatile content of norbornene in an EPDM polymer. Norbornene includes ethylene norbornene (ENB), vinyl norbornene (VNB), and combinations thereof. The method includes treating the EPDM polymer with superheated steam. This treatment is carried out for an effective duration to reduce the volatile norbornene content of the polymer. Volatile content refers to the amount of residual norbornene monomers in the polymer, preferably ENB, VNB, or combinations thereof. These residual monomers can escape as gases and be perceived as having a foul odor. The volatile content can be determined by GC-MS as described in the Experimental Section. The effective time depends on the amount of volatile norbornene present in the EPDM polymer, the temperature of the superheated steam, the contact time of the superheated steam, and the particle size of the treated EPDM polymer. The effective time can be determined by routine experiments, and the examples provided in this specification can be used as guidance. For example, the volatile content of an EPDM polymer with a volatile content of 10 ppm can be reduced to less than 1 ppm in less than 30 minutes.

[0014] In one embodiment of this disclosure, the method according to this disclosure provides an EPDM polymer having a volatile ENB content of less than 1.5 ppm, less than 1.0 ppm, or less than 0.60 ppm. In one embodiment, the method provides an EPDM polymer having an ENB volatile content of 0.2 to 0.4 ppm.

[0015] In one embodiment of this disclosure, the method according to this disclosure provides an EPDM polymer having a volatile VNB content of 0.01 to 1.4 ppm, 0.01 to 0.90 ppm, or 0.03 to 0.5 ppm. In one embodiment, the method provides an EPDM polymer having a VNB volatile content of 0.02 to 0.04 ppm.

[0016] In one embodiment of this disclosure, the method according to this disclosure provides an EPDM polymer having a combined content of less than 1.5 ppm, less than 0.95 ppm, or less than 0.60 ppm of volatile ENB and VNB. In one embodiment, the method provides an EPDM polymer having a combined volatile content of 0.2 to 0.4 ppm of ENB and VNB. Preferably, the content of volatile VNB in ​​the combined content of volatile ENB and VNB is at least 0.01 ppm or at least 0.02 ppm.

[0017] Superheated steam is steam with a temperature above its pressure boiling point, which occurs only when all liquid water has evaporated or been removed. Therefore, supersaturated steam is steam in which the operating temperature of the gas (i.e., steam) exceeds the temperature of saturated steam at a given operating pressure of interest. Superheated steam is physically produced by adding heat to saturated steam (a mixture of both liquid and gaseous phases of water), where the liquid phase has been completely removed. Once the liquid phase is eliminated, the addition of heat causes the temperature of the steam to rise above its associated saturation temperature. The resulting superheated steam then exhibits properties very close to those of a perfect gas, unlike the mixed-phase steam associated with a saturated steam environment. Compared to saturated steam, whose temperature is limited in the presence of liquid water, superheated steam in its pure gaseous form can reach temperatures consistent with the degree of heating supplied by the corresponding heat source. Furthermore, superheated steam cannot condense (i.e., produce the presence of liquid water) without lowering its temperature to the temperature of saturated steam at the pressure of interest. As long as the gas temperature is higher than the temperature of the saturated vapor at the corresponding pressure, it is in a superheated state, and the degree of superheat must be eliminated by some method or combination of heat transfer (i.e., conduction, convection and radiation) before condensation can occur.

[0018] Superheated steam can be generated by commercial installations (“superheaters”) or by methods known to those skilled in the art. For example, saturated steam can be generated by boiling water in a pressurized boiler to produce saturated steam at elevated pressure. The saturated steam can be released via nozzles to a lower pressure, such as ambient pressure, which causes a temperature drop while producing supersaturated steam. Maintaining the pressurized boiler at boiling conditions and elevated pressure to continue producing saturated steam allows for a stable supply of superheated steam. Figure 1 A pressure / temperature profile of steam, for example, generated in a boiler, is provided. When this steam is released to ambient pressure of 1 bar, the temperature decreases, as shown in the figure (solid line below). The steam is then supersaturated and has a certain degree of dryness, which allows for the removal of volatile norbornene. Preferably, superheated steam is used at a temperature of at least 100°C, for example, between 105°C and 200°C, preferably between 110°C and 180°C, or between 120°C and 160°C. Preferably, the treatment is carried out at ambient pressure, i.e., at 1 bar + / - 10%. Higher or lower pressures can be used, where the preferred temperature ranges can differ.

[0019] The EPDM polymer processed according to the method disclosed herein is preferably in solid form, more preferably in particulate form, such as fine particles, granules, or pellets. The size of the polymer particles is not particularly limited, but is preferably larger than 1 mm (in at least one dimension) to avoid agglomeration. Polymer granules are typically obtained from post-processing procedures of the polymerization process, typically after the solvent has been removed. Fine particles are typically obtained by grinding polymer packs, for example by a granulator or other pulverizing means. Pellets are typically obtained by extruding the polymer and cutting the extruded strands into thin segments, which typically produces cylindrical particles. The pellets may have a diameter of at least 5 mm and a length of 5 mm perpendicular to that diameter. Typically, the length and / or diameter of the pellets is less than 20 cm, preferably less than 10 cm. Preferably, EPDM polymer particles with a moisture content of less than 10%, preferably less than 5%, more preferably less than 2%. Moisture is removed by superheated steam along with volatile norbornene, but this method is faster and more efficient when the moisture content remains low.

[0020] Preferably, when the polymer particles are treated with superheated steam, the polymer particles are at a temperature approximately the boiling point of water under the applied pressure, preferably approximately 100°C under ambient pressure. This temperature can be achieved by using superheated steam or other means, for example, using particles obtained directly from an extruder (e.g., a dewatering extruder or a pellet extruder). The polymer particles can be heated, for example, by using saturated steam and removing the condensate.

[0021] Treatment with superheated steam can be carried out in any suitable container or multiple containers. The treatment can be a single process or can be performed multiple times at intervals. Preferably, the treatment is continuous, wherein superheated steam is continuously removed and replaced with freshly supplied superheated steam. The container may have one or more nozzles and one or more outlets for superheated steam, through which the superheated steam is fed into the container. The treatment can be carried out in a single container or in a series of containers, for example, in parallel or sequentially. Preferably, the particles are moved during treatment, for example by an agitator or extruder screw or by a flow, preferably turbulent flow, generated by the superheated steam, to ensure efficient treatment and prevent agglomeration. The container may be equipped with additional mechanical crushing devices, such as blades, spikes, shredders, or grinders known in the art, to avoid agglomeration and clumping. Alternatively, the polymer can be fed through one or more crushing devices after treatment with superheated steam.

[0022] After treatment with superheated steam, the granules are cooled. The cooling step can be carried out with ambient air under moderate flow until conditions are met for bagging or compression into pouches. This superheated steam can be cooled and condensed, for example, via a heat exchanger. The condensate can be treated with purification methods (e.g., activated carbon or other absorbent materials) to remove any volatile norbornene it contains before being recycled. The treated polymer can be subjected to one or more molding processes. For example, instead of using granules as starting material, granules can be formed after superheated steam treatment. "Regranulation" can also be performed, whereby the granules undergo additional granulation to increase or decrease their size or change their shape.

[0023] The method disclosed herein can be performed continuously or in batches.

[0024] EPDM polymer

[0025] In principle, any EPDM polymer can be subjected to the methods disclosed herein. The methods disclosed herein only reduce the volatile content of the EPDM polymer, but do not change the composition of the polymer, i.e., the amount of polymeric units, their molecular weight, polymer structure (e.g., degree of branching or polydispersity), or its properties (e.g., Mooney viscosity or its mechanical properties).

[0026] EPDM polymers can have a molecular weight (Mw) of at least 50 kg / mol, at least 90 kg / mol, at least 120 kg / mol, or even at least 200 kg / mol. In one embodiment of this disclosure, the EPDM polymer has a molecular weight (Mw) of 50 kg / mol to 150 kg / mol. In another embodiment of this disclosure, the polymer has a Mw of at least 200 kg / mol, for example, about 200 kg / mol to about 600 kg / mol or about 200 kg / mol to about 500 kg / mol. It has been found that polymers with higher molecular weights, such as EPDM polymers having a molecular weight of at least 200 kg / mol, exhibit lower viscosity at high temperatures, such as at temperatures of about 100°C or above, as can be applied in the methods according to this disclosure. Therefore, the methods according to this disclosure are particularly suitable for EPDM polymers having a molecular weight (Mw) of at least 200 kg / mol, at least 250 kg / mol, at least 300 kg / mol, at least 375 kg / mol, at least 425 kg / mol, at least 530 kg / mol, or at least 600 kg / mol.

[0027] These polymers can have high or low number-average molecular weights (Mn). In one embodiment, the polymer used in the method according to this disclosure has an Mn of 40 kg / mol to 250 kg / mol.

[0028] These EPDM polymers can have a Mooney viscosity ML 1+4 of 20 and up to 200, preferably 20 to 150, more preferably at least 50 or at least 65 or at least 75 at 125°C.

[0029] Branched or linear polymers can be used. Preferably, the EPDM polymer is branched and preferably contains units derived from norbornene, which generates the branching, such as VNB, although other means of generating polymer branching can be applied in addition to or instead of VNB. The level of branching can be characterized by the parameter Δδ. Δδ (expressed in degrees) is the difference between a phase angle δ with a frequency of 0.1 rad / s and a phase angle δ with a frequency of 100 rad / s, as determined by dynamic mechanical spectrometry (DMS) at 125°C and 10% strain. Δδ as a measure of the amount of long-chain branched structures in the polymer has been described in HCBooij, Kautschuk + Gummi Kunststoffe [Raw Rubber, Rubber and Plastics], Vol. 44, No. 2, pp. 128-130, which is incorporated herein by reference. The lower the Δδ, the more branched structures are present in the polymer. In one embodiment of this disclosure, the EPDM polymer has a Δδ of 1 to 50. Preferably, the EPDM polymer has a Δδ of 2 to 20 or 3 to 15.

[0030] The polymers that can be used in the methods disclosed herein can be unimodal, bimodal, or multimodal; that is, in the chromatogram obtained by gel permeation chromatography (GPC), they can have a molecular weight distribution characterized by two peaks in the case of bimodal polymers or by more than two peaks in the case of multimodal polymers. Polymer blends can also be used.

[0031] In one embodiment of this disclosure, the EPDM polymer comprises at least 20% or at least 30% by weight ethylene-derived units. In another embodiment of this disclosure, the EPDM comprises 40 to 70 wt.%, preferably 44 to 68 wt.%, or 50 to 60 wt.%, of ethylene-derived units. Weight percentages are based on the total weight of the copolymer.

[0032] The ethylene used to manufacture EPDM polymers can be fossil-derived or derived from sustainable sources, such as plant-based or recycled materials, which may or may not be plant-based. In contrast to products derived from fossil sources, the use of products derived from natural sources has gained increasing attention as an effective means of reducing atmospheric carbon dioxide concentrations and thus contributing to the reduction of the greenhouse effect. Products derived from natural raw materials differ from fossil-derived products only in their renewable carbon content. This renewable carbon content can be certified using the methods described in ASTM D6866-18, “Standard Test Methods for Determining the Biobased Content of Solid, Liquid, and Gaseous Samples Using Radiocarbon Analysis.” In other words, carbon-containing products derived from natural sources have different amounts of C14 isotopes than those derived from fossil sources, but are chemically identical. The renewable carbon source may include one or more plant materials selected from the group consisting of: sugarcane, sugar beets, maple, jujube, sugar palm, sorghum, agave, corn, wheat, barley, rice, potato, cassava, sweet potato, algae, and fruit. The renewable carbon source may also include materials containing cellulose, including wood, straw, paper, wood pulp or paper pulp, and leaves. Bio-based ethylene can be obtained, for example, by fermenting a renewable carbon source to produce ethanol, followed by dehydration of the ethanol to produce ethylene. Higher alcohols may be formed as byproducts during fermentation, and bio-based ethanol is typically purified before dehydration. Alternatively, bio-based ethylene may be purified (e.g., distilled) to remove impurities. Ethanol of biological origin (called bioethanol) can be obtained by fermenting sugars derived from cultures (such as sugarcane and sugar beet cultures) or from hydrolyzed starch, which is then associated with other cultures (such as corn). Bio-based ethylene can be obtained from the hydrolysis products of cellulose and hemicellulose, which can be found in many agricultural byproducts such as straw and sugarcane husks. Fermentation can be carried out in the presence of various microorganisms, such as the yeast *Saccharomyces cerevisiae*. The resulting ethanol can be converted to ethylene, for example, through a catalytic reaction at temperatures above 300°C. A wide variety of catalysts can be used for this purpose. Examples of the production of bioethanol and its conversion to ethylene include U.S. Patent Nos. 9,181,143 and 4,396,789.

[0033] In addition to units derived from ethylene, the polymers disclosed herein also contain units derived from one or more α-olefins. An α-olefin is an olefin having a single aliphatic carbon-carbon double bond. The double bond is located at the terminal (α-position) of the olefin. α-olefins can be aromatic or aliphatic, straight-chain, branched, or cyclic. Typically, α-olefins have 3 to 20 carbon atoms. Preferred examples of α-olefins include, but are not limited to, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tetracene, 1-tetradecene, 1-pentadecaene, 1-hexadecene, 1-heptadecene, 1-heptadecene, 1-octadecene, 1-nonadecaene, 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-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, and 12-ethyl-1-tetradecene. Several α-olefins can be used in combination. Preferably, the α-olefin is propylene. Preferably, the EPDM polymer comprises at least 20%, preferably at least 29%, of propylene-derived units based on the total polymer weight. The α-olefin used may be fossil-derived or obtainable from sustainable sources, including but not limited to recycled materials.

[0034] In addition to ethylene and α-olefins, the EPDM polymer also contains units derived from at least one norbornene, preferably from ENB, VNB, or combinations thereof. In a typical embodiment disclosed herein, the EPDM polymer contains at least 2 wt.% and up to and including 20 wt.% of units derived from one or more norbornenes. Preferably, the EPDM polymer contains at least 2 wt.% and up to and including 20 wt.%, more preferably at least 3 wt.% and up to and including 15 wt.% of units derived from ENB. Furthermore, or as an alternative to ENB, the EPDM polymer contains units derived from VNB, for example, 0.2% to 10% by weight, or about 0.05 wt.% to about 5 wt.%, preferably 0.10 wt.% to 3 wt.% or 0.15 wt.% to 1.2 wt.% of units derived from VNB. In one embodiment of this disclosure, the EPDM polymer comprises 2 to 15 wt.% of units derived from ENB and 0.05 to 4 wt.% of units derived from VNB.

[0035] In one embodiment, the EPDM polymer has only units derived from ethylene, propylene, ENB, and optionally VNB, and has units derived from one or more other copolymerizable monomers (including, but not limited to, linear or branched α-ω dienes, cyclic dienes, and combinations thereof). In one embodiment, the EPDM polymer has only units derived from ethylene, propylene, ENB, and optionally VNB.

[0036] The EPDM polymer to be used in the methods disclosed herein can be obtained by any known method. Polymerization can be carried out in the gas phase, in a slurry, or in a solution of an inert solvent (preferably a hydrocarbon solvent). Polymerization can be carried out continuously, for example, in one or more continuous stirred tank reactors, one or more circulating reactors, or as a batch reaction in one or more batch reactors, or a combination thereof. Continuous reactions can be carried out adiabatically or non-adiabatically. Multiple reactors can be used and can be connected in series or parallel. The solvent and monomer can be cooled before entering the reaction for temperature control, or can be evaporated for temperature control. Preferably, the EPDM polymer is obtained by solution polymerization. Preferred solvents include one or more inert hydrocarbon solvents. Suitable solvents include C 5-12 Hydrocarbons, such as pentane, hexane, heptane, octane, cycloheptane, cyclohexane, methylcyclohexane, methylcycloheptane, pentamethylheptane, hydrogenated naphtha, their isomers, and mixtures thereof. In another embodiment, polymerization is carried out by slurry polymerization.

[0037] Polymerization may include the use of one or more chain transfer agents to control the molecular weight of the polymer. Chain transfer agents include hydrogen, compounds having reactive hydrogen, diethylzinc, and combinations thereof.

[0038] EPDM polymers can be produced using one or more conventional polymerization catalysts suitable for the polymerization of the corresponding polymer to be produced. Typical examples include Ziegler-Natta catalysts, organometallic catalysts, or metallocene catalysts. Ziegler-Natta catalysts are polymerization catalysts based on transition metal halides, particularly titanium or vanadium. Metallocene catalysts are organometallic catalysts in which a metal (typically Ti, Hf, or Zr) is bonded to at least one cyclic organic ligand, preferably at least one ligand based on cyclopentadienyl, fluorenyl, or indene. Catalysts in which the metal is bonded to two anionic aromatic ligands are typically referred to in the art as “metallocene catalysts.” Catalysts in which the second anionic aromatic ligand is replaced by another organic ligand are referred to as “semi-metallocene catalysts.” Metal catalysts in which both anionic ligands are replaced by organic residues are referred to in the art as “post-metallocene catalysts.” Metallocene catalysts include metallocene, post-metallocene, and semi-metallocene catalysts. Suitable metallocene polymerization catalysts are known in the art and described, for example, in WO 2005 / 090418 A1, WO 2016 / 114914 A1, WO 2017 / 048448, and US2015 / 0025209 A1, all of which are incorporated herein by reference.

[0039] One or more cocatalysts can be used in polymerization. Cocatalysts are also referred to in the art as "activators". The presence of a cocatalyst typically increases the rate of polymerization of olefins. Cocatalysts can also affect the molecular weight, degree of branching, comonomer content, or other properties of the polymer. Typical cocatalysts include, but are not limited to, boron-containing activators, including boranes or borates.

[0040] Other cocatalysts include, but are not limited to, alkylaluminum, alkylaluminum halides, and aluminum oxanes.

[0041] Impurities can damage catalysts by reducing their activity. Those skilled in the art of polymerization refer to compounds that react with such impurities and convert them into compounds harmless to catalyst activity as scavengers. Scavengers can be the same compound as the co-catalyst, and in that case, they are typically applied in amounts exceeding those required for complete catalyst activation. Scavengers can be used in combination with hindered hydrocarbons, preferably hindered phenols, containing Group 15 or 16 heteroatoms (preferably O, N, P, and S atoms, more preferably O and N heteroatoms).

[0042] After polymerization, the reaction mixture is fed to a post-treatment section where the solvent is removed and the polymer is separated. The post-treatment section may contain a devolatilization unit where the solvent and / or unreacted monomers are removed and recycled. The solvent is typically removed via one or more stripping towers. If producing an oil-extended polymer, as is known in the art, one or more incremental oils may be added to the reaction mixture prior to solvent removal. Suitable additive oils include, but are not limited to, petroleum products such as aromatic and naphthenic oils; polyalkylbenzene oils; monoesters of organic acids such as alkyl and alkoxyalkyl oleates and stearates; diesters of organic acids such as dialkyl, dialkoxyalkyl and alkylaryl phthalates, terephthalates, sebates, adipates and glutarates; glycol diesters such as triethylene glycol dialkylates, tetraethylene glycol dialkylates and polyethylene glycol dialkylates; trialkyl trimellitic acid esters; trialkyl phosphates, trialkoxyalkyl phosphates, alkyl diaryl phosphates and triaryl phosphates; chlorinated paraffin oils; coumarone-indene resins; pine tar; vegetable oils, including castor oil, tall oil, rapeseed oil and soybean oil, and including their esters and epoxidized derivatives.

[0043] After solvent removal, solid polymer particles (granules) are obtained, which can be treated with superheated steam according to the method disclosed herein to reduce volatile content. Alternatively, polymer particles obtained from compressed granules (bags) or sheets can be used. Preferably, the method according to the disclosure for providing an EPDM polymer with low volatile content is carried out using EPDM granules that have been extruded and cut into pellets.

[0044] In one aspect, a polymer composition is provided comprising at least 95% by weight, or at least 99% by weight, of at least one EDPM polymer, wherein the polymer composition has an ENB volatile content of less than 1.5 ppm, less than 0.95 ppm, or less than 0.60 ppm, and optionally a VNB volatile content of 0.01 to 0.90 ppm or 0.03 to 0.5 ppm. Since the method according to this disclosure only changes the volatile content of the polymer without altering its composition or properties, the EPDM polymer of the polymer composition is as described above. In one embodiment of this disclosure, the polymer composition has a combined volatile content of ENB and VNB of less than 1.5 ppm, less than 0.95 ppm, or less than 0.60 ppm, wherein the minimum VNB content is 0.01 ppm or 0.03 ppm. Preferably, the polymer composition is in the granular form as described above. In one embodiment of this disclosure, the EPDM polymer is oil-extended, and the EPDM polymer contains one or more incremental oils. Preferably, the weight ratio of the incremental oil to the EPDM polymer in the oil-extended polymer composition is 1:1 to 1:20.

[0045] EPDM compositions are typically provided as granules as described above or as rubber packages. Such packages typically have a length of at least 30 cm, a width of at least 20 cm, and a height of at least 10 cm. Polymer compositions can be used to manufacture curable rubber compositions. Typically, polymer compositions are combined with one or more additives, typically curing agents, to provide curable rubber compositions. Rubber additives and auxiliaries as known in the art can be added to the curable composition. The curable composition can be cured to produce rubber articles. Rubber compositions are typically prepared by blending the components in a kneader or on a two-roll mill. Such blends typically contain 10% to 95% rubber by weight, and the remainder includes fillers, curing agents, processing additives (such as processing oils), and other additives tailored to the articles to be produced by subjecting the rubber blend to curing and molding. To increase the bio-based material content of rubber compounds and reduce the CO2 footprint of products made from rubber compounds, bio-based or other sustainably sourced ingredients can be used, such as those described in Martin van Duin and Philip Hough, “Green EPDM Compounds”. Kautschuk Gummi Kunststoffe [Raw Rubber, Rubber and Plastics], 01-2, 2018, pp. 26-37, and Martin van Duin et al. in Chapter 5, Lightweight and Sustainable Materials for Automotive Applications As described in *Lightweight and Sustainable Materials for Automotive Applications*, CRC Press, 2017. For example, recycled carbon black (rCB) can be used instead of conventional carbon black fillers. Recycled carbon black can be obtained, for example, from the recycling of waste tires, roofing membrane waste, conveyor belt waste, or hose waste, and is usable. Silica-based fillers obtained from rice husk ash can be used instead of conventional silica fillers. Instead of fossil-based mineral processing oils, sustainable oils from recycled oils (e.g., from automotive engine oil recycling) can be used as processing oils. Vegetable-based oils can also be used as processing oils, such as corn oil, coconut oil, linseed oil, rapeseed oil, soybean oil, or other vegetable oils.

[0046] The rubber composition is curable and can be cured to provide a vulcanized rubber compound or "vulcanized rubber". Curing agents as known in the art can be used. Suitable curing (vulcanizing) agents include, but are not limited to, sulfur, thiochlorides, sulfur dichloride, 4,4'-dithiodimorpholine, dimorpholine disulfide; alkylphenol disulfide, tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), selenium dimethyl dithiocarbamate, and organic peroxides. Organic peroxides include, but are not limited to, dicumyl peroxide (DCP), 2,5-di(tert-butylperoxy)-2,5-dimethylhexane (DTBPH), di(tert-butylperoxyisopropyl)benzene (DTBPIB), 2,5-di(benzoylperoxy)-2,5-dimethylhexane, 2,5-(tert-butylperoxy)-2,5-dimethyl-3-hexyne (DTBPHY), di-tert-butyl peroxide and di-tert-butylperoxide-3,3,5-trimethylcyclohexane (DTBTCH), or mixtures of these peroxides. Sulfur or sulfur-containing curing agents are preferably used in an amount of 0.1 to 10 phr. Organic peroxide-based curing agents can be used in an amount of 0.1 to 15 phr, preferably 0.5 to 5 phr. Sulfur can be used in combination with one or more vulcanization accelerators and activators. Peroxide-based curing agents can be used in combination with one or more active auxiliaries. Peroxide-based curing agents can also be used in combination with sulfur or sulfur-based curing agents. Other curing agents include methyl phenolic resins or methyl phenolic resin-based curing agents.

[0047] filler

[0048] Typically, fillers can be used in amounts from 20 to 500 phr. Fillers such as those known in the art can be used, including carbon black, silica, calcium carbonate, talc, and clay. The fillers can be surface-treated, for example, with silanes. Combinations of two or more of these fillers can be used. Preferably, the filler comprises carbon black and / or silanized silica. Additional fillers may comprise one or more rubbers other than the copolymers disclosed herein. Preferably, the filler is derived from a sustainable source or obtained from plant-based materials (e.g., lignin-based materials).

[0049] Other rubber additives (rubber auxiliaries)

[0050] Other rubber additives include those commonly used in rubber compounding. Examples include, but are not limited to, antioxidants (e.g., hindered phenols, such as those commercially available from BASF under the trade names IRGANOX 1010 or IRGANOX 1076); phosphites (e.g., those commercially available under the trade name IRGAFOS 168); desiccants (e.g., calcium oxide); tackifiers (e.g., polybutene, terpene resins, aliphatic and aromatic hydrocarbon resins, alkali metal stearates and glyceryl stearate, and hydrogenated rosin, etc.); adhesives; heat stabilizers; anti-caking agents; mold release agents; antistatic agents; pigments; colorants; dyes; processing aids (e.g., ointments, fatty acids, stearates, polyethylene glycol or diethylene glycol); antioxidants; heat stabilizers (e.g., poly-2,2,4-trimethyl- 1,2-Dihydroquinoline or 2-mercaptobenzimidazole zinc); UV stabilizers; anti-ozone agents; foaming agents and mold release agents; distributing agents or processing aids such as talc or metal salts (e.g., zinc stearate, magnesium stearate or calcium stearate); and plasticizers, plasticizer lubricants, paraffin wax, liquid paraffin wax, petroleum asphalt, low molecular weight polyisobutylene or polybutene, liquid EPDM or EPM, coal tar pitch, castor oil, linseed oil, beeswax, atactic polypropylene and coumarone indene resin. Plasticizers can typically be used in amounts from 20 to 250 phr.

[0051] Products

[0052] To manufacture articles, rubber compounds are subjected to curing and molding. Curing (also known as “vulcanization”) can occur before, during, or after molding. Articles made using EPDM polymers according to this disclosure contain polymers in cured form, i.e., polymers crosslinked with themselves or with other crosslinkable components (e.g., other curable rubbers) in the composition used to manufacture the articles. To manufacture articles, rubber compositions can be subjected to one or more curing and molding processes, including but not limited to extrusion molding, compression molding, injection molding, foaming, extrusion blow molding, injection blow molding, ISBM (injection stretch blow molding), and combinations thereof. Typical articles include, but are not limited to, foams, sponges, hoses, belts, seals, engine racks, roofing materials, or gaskets. The EPDM polymers disclosed herein can be used to manufacture layers in layered articles, such as as an outer or inner layer. Examples of layered materials include hoses (including garden hoses, coolant hoses, and hoses for under-hood applications) and belts (including but not limited to conveyor belts, escalator belts, and engine belts). The oil-extended ethylene-polymers disclosed herein can be used to reduce noise or as vibration damping materials, for example, as engine racks or in other applications. The EPDM polymers disclosed herein can be used as sealing materials or for manufacturing seals. Seals include solid seals. Solid seals mean that the material is non-foamed and, unlike foamed materials, does not contain a honeycomb or sponge-like structure. Examples of solid seals include seals that make articles airtight, watertight, or reduce vibration. Examples include O-rings and flanges for openings in, for example, washing machines and other devices. The EPDM polymers disclosed herein can also be used to manufacture foamed articles, including sponge-like seals or foamed seals.

[0053] The EPDM polymers disclosed herein can be combined with other polymers to manufacture composites, blends, or multilayer articles. Such polymer resins include, for example, polyethylene, polyethylene copolymers such as ethylene maleic anhydride, polypropylene, polystyrene, polybutadiene, polyvinyl chloride, ethylene-vinyl acetate copolymer (EVA), polyesters such as polyethylene terephthalate (PET), polyhydroxyalkanoates (PHA), high-impact polystyrene (HIPS), and acrylonitrile butadiene styrene (ABS), polyurethane, elastomers such as polysulfide rubber, ethylene propylene rubber (EPM), EPDM polymers other than those disclosed herein, poly(ethylene-methyl acrylate), poly(ethylene-acrylate), vinyl silicone rubber (VMQ), fluorosilicone (FVMQ), nitrile rubber (NBR), acrylonitrile-butadiene rubber, etc. Styrene-butadiene rubber (ABS), styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene-butene-styrene triblock copolymer (SEBS), polybutadiene rubber (BR), styrene-isoprene-styrene block copolymer (SIS), partially hydrogenated acrylonitrile-butadiene (HNBR), natural rubber (NR), synthetic polyisoprene rubber (IR), chloroprene rubber (CR), polychloroprene, bromobutyl rubber, chlorobutyl rubber, chlorinated poly(ethylene), vinylidene fluoride copolymer (CFM), silicone rubber, vinyl silicone rubber, chlorosulfonated poly(ethylene), fluorinated elastomers, elastic polyolefins such as ethylene C3-C12 α-olefin copolymers, and combinations thereof. In specific embodiments disclosed herein, the copolymers can be used to manufacture thermoplastic vulcanizates (TPVs). TPVs comprise finely dispersed rubber particles within a thermoplastic matrix. Advantageously, the rubber particles are crosslinked to promote elasticity. The dispersed rubber phase is also referred to as the discontinuous phase, and the thermoplastic phase is also referred to as the continuous phase. TPV offers the benefits of the elastomeric properties provided by rubber and the processability of thermoplastic materials. TPV is prepared by dynamic curing. In dynamic curing, rubber is cured with one or more curing agents while being mixed with at least one thermoplastic resin under shear stress (e.g., simultaneously subjecting the polymer to an elevated temperature, preferably above the melt temperature of the thermoplastic polymer). Typically, dynamic curing is carried out in an extruder under the following conditions: the rubber is ground into small particles and dispersed in molten thermoplastic material, and then cured, and the resulting TPV is extruded from the extruder. Thermoplastic resins typically include polypropylene, polyethylene, combinations thereof, and combinations with other thermoplastic resins. Examples of TPV and methods for producing TPV are described, for example, in International Patent Application WO 2019199486 A1, which is incorporated herein by reference, particularly pages 11-15 for selecting thermoplastic polymers, and particularly pages 21-25 for methods for manufacturing TPV.In one embodiment of this disclosure, a composition for manufacturing thermoplastic vulcanizate (TPV) is provided, the composition comprising an EPDM polymer according to this disclosure, a thermoplastic resin (preferably selected from polypropylene, polyethylene, or combinations thereof), and a curing agent.

[0054] In another preferred embodiment of this disclosure, a method for producing a thermoplastic vulcanizate (TPV) is provided, the method comprising blending an EPDM polymer according to this disclosure, a thermoplastic resin (preferably selected from at least one polypropylene, at least one polyethylene, or a combination thereof), and a curing agent, and subjecting the blend to dynamic curing, preferably in an extruder, wherein, preferably, the EPDM polymer and the thermoplastic resin are blended at a temperature above the melt temperature of the resin before the curing agent is added to the blend. A thermoplastic vulcanizate (TPV) obtained by this method is also provided.

[0055] The EPDM polymer disclosed herein is preferably used for "indoor" applications, such as for manufacturing articles for use in the passenger cabin of motor vehicles, including TPVs, window seals and door seals.

[0056] This disclosure will now be further illustrated by examples; however, it is not intended to limit this disclosure to the examples presented.

[0057] Instances and methods

[0058] method

[0059] Volatile content of ENB and VNB

[0060] The volatile content of ENB and VNB was determined by headspace GC-MS. Headspace GC-MS measurements were performed at a measurement temperature of 250°C. The polymer sample (2 g) was cut into small pieces approximately 1 mm in size. If condensation was present on the sample surface, it was wiped dry with a cloth. Four hours prior to analysis, the sample was conditioned in an oven at 23 ± 2°C and 50 ± 10% rH. For analysis, the sample was placed in a standard headspace vial with a screw cap. The vial was heated to 150°C for 30 minutes, after which a defined volume of headspace gas (Agilent headspace sampler 7697A) was removed and injected into a GC column (Agilent DB-624, 250°C, 1 ml / min He gas). Quantification was based on prior calibration using known amounts of VNB and ENB.

[0061] Polymer composition: The composition of a copolymer can be determined using Fourier transform infrared spectroscopy (FT-IR) based on ASTM D3900 (revised 2017) for the C2 / C3 ratio and D6047 (revised 2017) for the diene content on the pressed polymer film.

[0062] Branching: Δδ is a measure of the presence of long-chain branches in a polymer structure. The lower the Δδ value, the more long-chain branches are present in the polymer. This method is described in HCBooij, in Kautschuk + Gummi Kunststoffe [Raw Rubber, Rubber and Plastics], Vol. 44, No. 2, pp. 128-130, 1991.

[0063] Molecular weight: Molecular weight (weight-average molecular weight (Mw), number-average molecular weight (Mn), and Mz value) and molecular weight distribution (MWD) were determined by gel permeation size exclusion chromatography (GPC) using the Polymer Char GPC-IR system from PolymerCharacterization SA, Valencia, Spain. The size exclusion chromatograph was equipped with an online viscometer (Polymer Char V-400 viscometer), an online infrared detector (IR5 MCT), three AGILENT PL OLEXIS columns (7.5 x 300 mm), and a Polymer Char autosampler. The system was universally calibrated using polyethylene (PE) standards.

[0064] The polymer sample (concentration range 0.3–1.3 mg / mL) was weighed into vials of the PolymerChar autosampler. These vials were automatically filled into the autosampler with solvent (1 g / L di-tert-butyl-p-cresol (DBPC) stabilized 1,2,4-trichlorobenzene). The sample was incubated in a high-temperature oven (160°C) for 4 hours. After this dissolution time, the sample was automatically filtered through an in-line filter before injection into the column. The chromatographic system was run at 160°C. The flow rate of the 1,2,4-trichlorobenzene eluent was 1.0 mL / min.

[0065] Mooney viscosity: The Mooney viscosity of the copolymer samples can be measured according to ISO 289, revised 2015. The measurement conditions are ML(1+4) at 125°C.

[0066] Example

[0067] Examples 1 to 7 (Comparison)

[0068] The volatile matter content (ENB and VNB content) of commercial EPDM polymers from various suppliers was analyzed by headspace GC-MS. The results are shown in Table 1. All samples had a pronounced norbornene odor.

[0069] From Kumho Polychemical Co Ltd; From Mitsui Chemicals. From Dow Chemical Inc. Examples 8 and 9 (VOC removal via wet post-treatment; comparison) Example 8 EPDM polymer (Mounney viscosity ML1+4 (125°C) 80 MU, 48 wt% ethylene content, 4.5 wt% ENB content, and less than 1 wt% VNB content) was produced by solution polymerization as described in WO 2005 / 090418 and separated by wet stripping. For the wet stripping process, the reaction mixture was fed into a first stripping tower, where polymer pellets were formed and most of the low-boiling components and solvent were evaporated. The polymer pellets were then passed through a series of additional steam stripping towers for further removal of volatile organic compounds. The pellets were then separated from water by mechanical dehydration, an extrusion expander process, and a subsequent pellet dryer. The time on the pellet dryer was 15 minutes. The VOC content of two samples was measured, and these two samples had ENB contents of 8.97 / 8.87 ppm and VNB contents of 1.27 / 1.37 ppm, respectively. These samples had a distinctive norbornene odor.

[0070] Example 9

[0071] Example 8 was repeated, except that the steam feed and temperature in the stripping tower were increased, which reduced the particle size. The throughput was reduced to 47% compared to Example 8. The time in the particle dryer was increased to 30 minutes. In the dryer, the particle size decreased. The volatile matter content of the two samples was measured. VOC contents were detected at 1.46 / 1.34 ppm ENB and 0.94 / 0.92 ppm VNB. Only a faint odor of norbornene was noted.

[0072] Example 10 (VOC reduction via superheated steam)

[0073] The polymer obtained in Example 8 was granulated in an extruder to form cylindrical pellets with a diameter of approximately 10 mm and a height of 5 mm. The typical odor of norbornene was noted. The pellets were placed in a 10-l glass reactor, which was heated to above 100°C via an external heating jacket. Approximately 200 g of polymer pellets were placed in the container to obtain a loose packing. Steam was generated in a steam boiler at a pressure of 3 bar and directed from the boiler to the bottom of the stripping vessel of the glass reactor via insulated pipes to create a gentle steam flow through the pellets, while the pellets were agitated at 60 rpm using an agitator with a PTFE-lined shaft and metal paddle. The steam was reduced from 3 bar to ambient pressure (1 bar) via a pressure relief nozzle between the boiler and the reactor to ensure that the steam entering the reactor was superheated. A Morrillon plot of the steam used for an isenthalpic process showed that the expanding steam was superheated at ambient pressure to a temperature of 124°C. The dryness of the steam was calculated to be 8.25%. The pellets were stripped with superheated steam for 2 hours. Samples were taken every 30 minutes, and their VOC content was analyzed by headspace GC-MS.

[0074] Example 11

[0075] Example 10 was repeated, except that superheated steam was generated by a pressure drop from 4 bar to ambient pressure. According to the Morrill diagram, the steam was superheated to a temperature of 131°C and had a dryness of 9.82%.

[0076] The volatile content (the sum of volatile ENB and VNB) in Examples 10 and 11 is shown in Table 2 as stripping time decreases. The sample with time = 0 refers to untreated polymer pellets.

[0077] Table 2

[0078] EPDM polymers with a combined volatile content of less than 1 ppm of ENB and VNB typically do not exhibit a pronounced norbornene odor. As can be seen from Table 2, this condition was achieved within 1 hour in Example 10 and within less than 30 minutes in Example 11.

[0079] Example 12

[0080] Example 10 was repeated, except that superheated steam was generated by a pressure drop from 4.5 bar to ambient pressure. After the pressure drop, the superheated steam had a temperature of 136°C and a calculated dryness of 10.52%. Fine particles with a combined volatile content of approximately 5 ppm of ENB and VNB were used. The volatile content decreased by approximately 50% within 15 minutes, which is faster than the rate observed in Examples 10 and 11, and indicates that superheated steam accelerates the removal of volatile ENB and VNB with increasing temperature.

[0081] Example 13 (Removal of volatile ENB and VNB from polymer debris using superheated steam)

[0082] Polymer pellets were produced as in Example 8, but instead of drying them on a drying belt, these pellets were treated with superheated steam. The experimental setup of Example 10 was used. Superheated steam was produced as described in Example 8, except that the pressure drop was from 4.5 bar to ambient pressure. The contents of volatile VNB and ENB were reduced from 59.6 / 52.9 ppm ENB and 5.0 / 4.0 ppm VNB before stripping to less than 5 ppm at 30 minutes, and further reduced to 1.08 / 0.96 ppm ENB and 0.09 / 0.09 ppm VNB, respectively, within 60 minutes.

Claims

1. A method for providing an EPDM polymer with a reduced volatile ENB content, the method comprising: (i) Provide an EPDM polymer comprising, by weight, 1% to 20% of ENB-derived units based on the total weight of the EPDM polymer. (ii) Treat the EPDM polymer of step (i) with superheated steam to reduce the volatile ENB content of the EPDM polymer; (iii) Stop using superheated steam treatment. (iv) Optionally, the polymer may be cooled to room temperature.

2. The method of claim 1, further comprising step (ia) which is performed simultaneously with or after step (i) and simultaneously with or before step (ii), wherein step (ia) comprises heating the EPDM polymer to a temperature above the boiling point of water at the current pressure, wherein the current pressure is selected from ambient pressure, pressure above ambient pressure, and pressure below ambient pressure.

3. The method as described in claim 1, wherein, The EPDM polymer in step (i) has 0.2% to 10% by weight of VNB-derived units based on the total weight of the EPDM polymer.

4. The method of claim 1, wherein, The EPDM polymer in step (i) is shaped into one or more granules.

5. The method of claim 1, further comprising step (v), which includes molding the EPDM polymer into one or more granules, and wherein step (v) is performed after step (ii), after step (iii), or after step (iv).

6. The method of claim 1, wherein, The EPDM polymer with reduced volatile ENB content has an ENB volatile content of less than 1.5 ppm, less than 1.0 ppm, or less than 0.60 ppm, as determined by headspace GC-MS according to the measurement method described in the Experimental Section.

7. The method of claim 1, wherein, The EPDM polymer with reduced volatile ENB content has a combined volatile ENB and VNB content of less than 1.0 ppm and a volatile VNB content of 0.1 to 0.90 ppm or 0.2 to 0.5 ppm, as determined by headspace GC-MS according to the measurement method described in the Experimental Section.

8. The method of claim 1, wherein, The EPDM polymer with reduced volatile ENB content has a Mw of at least 50 kg / mol or at least 125 kg / mol.

9. The method of claim 1, wherein, The EPDM polymer with reduced volatile ENB content has a Mooney viscosity ML 1+4 of 20 and up to 120 at 125°C.

10. The method of claim 1, wherein, This EPDM polymer with reduced volatile ENB content has a branching index Δδ of 2 to 20°.

11. A polymer composition comprising at least 95% by weight, or at least 99% by weight, an EDPM polymer having 1% to 20% by weight units derived from ENB and optionally 0.2% to 10% by weight units derived from VNB, wherein the polymer composition has an ENB volatile content of less than 1.5 ppm, less than 1.0 ppm, or less than 0.60 ppm.

12. The polymer composition of claim 12, wherein, The polymer composition has a VNB volatile content of 0.01 to 1.9 ppm or 0.1 to 0.5 ppm.

13. The polymer composition of claim 12, wherein, The polymer composition is in the form of granules.

14. A method of manufacturing TPV, the method comprising (i) extruding a blend produced by combining at least one polymer composition as described in claims 11-13 with a thermoplastic polymer, preferably a polypropylene polymer, and (ii) extruding the resulting mixture in the presence of at least one curing agent to produce TPV, wherein, The blend is produced before or during the extrusion.

15. An article obtained using the polymer composition as described in any one of claims 11-13.

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