Rubber compositions for dynamic or static applications, methods for manufacturing the same, and products incorporating the composition.

Abstract

The present invention relates in particular to a crosslinkable rubber composition and to a method for its preparation, said composition being based on an elastomer and comprising a crosslinking system and a thermoplastic phase having a melting point Tm and dispersed in the form of nodules, including the following products: a) the product of a melt reaction of said elastomer with other components by thermomechanical processing, excluding crosslinked systems; b) Products produced by mechanical action with prior addition of a crosslinking system. According to the present invention, the nodules have a size of 10 nm to 10 μm, a) comprises heating the reaction mixture above Tm and maintaining it for a predetermined holding time, and the crosslinking system comprises sulfur if the elastomer is unsaturated and the phase comprises saturated polymer chains, or hydrogen peroxide if the elastomer is saturated.

Description

[Technical Field]

[0001] The present invention relates to a crosslinkable rubber composition, a method for producing the same, a crosslinked rubber composition, a mechanical component having a dynamic function, and a sealing element comprising at least part of the crosslinked rubber composition. In particular, it is applicable to all industrial applications using the crosslinked rubber composition, which include, but are not limited to, the mechanical component having a dynamic function selected from vibration-resistant supports and elastic joints for electric vehicles or industrial equipment, and the sealing element selected from seals for vehicle bodies and seal profiles for buildings. [Background technology]

[0002] Traditionally, reinforcing elastomers in rubber compositions is achieved by adding fillers such as carbon black or silica to improve the mechanical properties of the composition through hydrodynamic effects, interactions between the elastomer and the filler, and interactions within the filler itself. These fillers, in powder form, are dispersed in the rubber by thermomechanism during the compounding of the composition's components, by heating the mixture to a maximum temperature of typically 100-130°C, usually below 150°C, in the case of ethylene-propylene-diene (EPDM) terpolymer type rubber filled with carbon black, separate from crosslinking systems.

[0003] However, these filler-elastomer and filler-filler interactions cause undesirable phenomena related to hysteresis loss, which are usually referred to as the Payne effect, and in particular, at low temperatures in crosslinked rubber compositions subjected to dynamic stress, result in nonlinearity (i.e., amplitude stiffening) and stiffening. This stiffening, due to the aforementioned interactions with the reinforcing fillers used, results in dynamic properties that can prove unsatisfactory for the composition, and these dynamic properties typically result in the complex shear modulus G of the composition at two dynamic strain amplitudes. * It can be evaluated by measuring the ratio of the storage modulus G' to the complex modulus G.* is, formula G * Defined by =G'+iG'': G': G, known as the storage modulus or modulus of elasticity. * The actual part, G' (i.e., stored and fully recovered energy) characterizes the rigid or viscoelastic behavior of the composition. G'', known as the loss or emission coefficient G'' that characterizes the viscous behavior of the composition. * The imaginary part of (i.e., the energy dissipated in the form of heat; it has been pointed out that the ratio G'' / G' defines the tan-delta loss coefficient).

[0004] This ratio typically corresponds to G' measured at a low dynamic strain amplitude versus G' measured at a high dynamic strain amplitude, with the two moduli G' measured at the same frequency and temperature (e.g., G'0.5% / G'20%). In known methods, G'0.5% / G'20% is typically 1.80–2.00 for a polyisoprene (IR)-based rubber composition reinforced with 40 phr of N330 grade carbon black for use in dynamic applications (phr: parts by weight per 100 parts by weight of elastomer). In fact, it is known that in reinforced materials, viscoelastic behavior begins at low dynamic strain amplitudes, and G' substantially decreases with increasing strain.

[0005] To overcome the aforementioned drawbacks of conventional filled compositions, which involve high hysteresis loss, US 8 247 494 B2 discloses a rubber composition that does not contain carbon black or silica and is reinforced with a thermoplastic resin dispersed in the form of distinct domains within a continuous phase of crosslinked olefinic rubber. This document teaches the crosslinking of rubber by hydrosilylation alone for silicon crosslinking.

[0006] Japanese Patent Publication No. 2002-155148 discloses a method for producing a rubber composition containing a polyolefin resin micro-dispersed in an olefin rubber by compounding components at a temperature below the melting point of the polyolefin resin. These components, in addition to the rubber and resin, include at least 20 phr of carbon black as a reinforcing filler, and the resulting mixture is crosslinked with sulfur or a peroxide system.

[0007] EP 3 243 874 A1 discloses a tire rubber composition intended to exhibit improved ozone resistance, comprising a matrix of a nonpolar polymer derived from a conjugated diene (an unsaturated rubber such as polybutadiene), in which the matrix domains of the olefin polymer are dispersed such that the interfaces between the matrix and these domains include covalent bonds. The document teaches the use of peroxide crosslinking systems (e.g., those composed of ethylene-propylene copolymers) for crosslinking the unsaturated rubber and saturated domains, as well as sulfur crosslinking systems (e.g., those composed of ethylene-propylene-diene (EPDM) terpolymers) for co-crosslinking this unsaturated rubber and similarly unsaturated domains.

[0008] During these recent studies, the applicant has focused on modifying the process for formulating these compositions to incorporate separate thermoplastic domains into a rubber matrix such that these known compositions have reinforcing properties similar to those obtained with conventional carbon black or silica-type reinforcing fillers, and without impairing, or even improving, their mechanical properties. [Overview of the project]

[0009] One of the objectives of the present invention is to propose a rubber composition that not only overcomes the high hysteresis loss of carbon black or silica-filled compositions, but also has substantially retained reinforcing properties and improved mechanical properties compared to a control composition based on the same elastomer matrix and the same crosslinking system, but filled with carbon black.

[0010] This objective is achieved, surprisingly, by the applicant's discovery that a reaction mixture containing an elastomer and a thermoplastic polymer having a melting temperature Tm, when a melting reaction is carried out by thermomechanizing while heating to a maximum compounding temperature Ta that is higher than Tm and maintained for a sufficient time, yields a mixture that, after adding a specific crosslinking system from the perspective of the selected elastomer and optionally the thermoplastic polymer, yields a crosslinkable composition in which the thermoplastic polymer is uniformly dispersed in the elastomer in the form of nodules that are advantageously spherical or elliptical and of nanometer or micrometer size. In particular, this mixture allows the crosslinkable composition to obtain improved scorch resistance and the same level of reinforcement and improved mechanical properties even after thermal oxidation aging by UV irradiation or aging, compared to a control composition based on the same components (e.g., the same elastomer, the same crosslinking system), except that carbon black is included instead of the thermoplastic polymer in the crosslinkable composition.

[0011] More specifically, the crosslinkable rubber composition according to the present invention is based on at least one elastomer, the composition comprising a crosslinking system and other components comprising a thermoplastic polymer phase having at least one melting point Tm and dispersed in the at least one elastomer in the form of nodules, the crosslinkable composition comprising the following products: a) A product of a melt reaction to obtain a precursor mixture of a crosslinkable composition by thermomechanical processing of a reaction mixture comprising at least one elastomer and the other components excluding the crosslinking system, and then, b) Products of machining the precursor mixture to which a crosslinking system has been added in advance, for obtaining a crosslinkable composition.

[0012] According to the present invention, a nodule (for example, spherical or elliptical) has a weight-average maximum transverse dimension (e.g., diameter or major axis, respectively) of 10 nm to 10 μm, preferably 50 nm to 10 μm. The reaction involves heating the reaction mixture to a temperature higher than the highest melting temperature Tm of the at least one of the thermoplastic polymer phases and to a maximum compounding temperature Ta that is maintained during the holding time. The crosslinking system contains sulfur when the at least one elastomer is unsaturated and the thermoplastic polymer phase contains saturated polymer chains, and contains hydrogen peroxide when the at least one elastomer is saturated.

[0013] As used herein, the expression "based on" is understood to mean that the composition or component being considered has a preponderant range in weight, i.e., in mass fraction, exceeding 50%, preferably exceeding 75%, and in some cases up to 100%, and contains the component in question.

[0014] As used herein, the terms "unsaturated" and "saturated" are understood in a known manner to mean an elastomer / thermoplastic polymer containing at least one unsaturation (i.e., a double bond or a triple bond) and an elastomer / thermoplastic polymer not containing unsaturation (i.e., not containing a double bond or a triple bond), respectively.

[0015] Note that, unexpectedly, the crosslinkable composition according to the invention, in combination with the selection of a crosslinking system adapted to the elastomer and thermoplastic phases, has an optimized interface between the elastomer matrix and the thermoplastic nodules, and imparts improved or at least preserved properties to both the crosslinkable composition (in particular, scorch resistance) and the crosslinked composition (in particular, mechanical and reinforcing properties under static and dynamic stresses), enabling the formation of a dispersion of the thermoplastic phase in the form of nodules in the elastomer, which is obtained by said heating maintained at a high temperature (compared to the formulation of the same control composition based on the same components, except for the thermoplastic phase replaced by carbon black) by this molten reaction product obtained.

[0016] Also, the rubber composition according to the present invention should not be confused with a thermoplastic elastomer composition. This composition of the present invention is specifically characterized by the dispersion of the thermoplastic polymer phase in the at least one elastomer. Therefore, it should also be noted that the thermoplastic base is structurally very different from a thermoplastic vulcanizate containing a dispersion of rubber nodules.

[0017] Furthermore, it should be noted that the crosslinkable composition according to the present invention, in particular after these crosslinks, enables the following to be imparted to the crosslinked composition: - A significantly reduced density compared to the control composition reinforced with carbon black instead of nodules of the thermoplastic phase; - Electrostatic properties that are at least preserved or improved compared to those of the control composition and that do not substantially deteriorate after thermal oxidative aging or aging by UV; - A conductivity that is minimized compared to this control composition.

[0018] According to the present invention, the weight average maximum cross-sectional dimension of the nodules of the thermoplastic polymer phase is measured in particular by a scanning electron microscope (SEM) combined with an X-ray photon detector (SEM / EDX) having a gold / palladium metal coating.

[0019] Advantageously according to the present invention, the nodules may have a weight average maximum cross-sectional dimension of 100 nm to 10 μm, and the holding time at the maximum blending temperature Ta is at least 10 seconds.

[0020] According to another aspect of the present invention, the crosslinkable composition may contain, as a powder filler dispersed in at least one elastomer, 0 to 100 phr (preferably 0 to 50 phr, more preferably 0 to 10 phr, or even further 0 to 5 phr) of an organic filler such as carbon black and 0 to 70 phr (e.g., 10 to 60 phr) of an unreinforced inorganic filler other than silica (phr: parts by weight per 100 parts by weight of elastomer), and advantageously, the crosslinkable composition may not contain any organic or inorganic powder filler at all.

[0021] In this specification, the term “filler” is understood to mean one or more individual fillers of a reinforcing grade or otherwise with respect to the elastomer, which are uniformly dispersed in powder form in the composition (as opposed to nodules of the present invention), and the term “inorganic filler” is understood to mean a transparent filler (sometimes called “white filler”) as opposed to organic fillers such as carbon black and graphite, for example.

[0022] Therefore, it should be noted that the compositions according to the present invention either do not contain carbon black, or in an indefinite embodiment, contain at most 100 phr (preferably at most 50 phr, or at most 10 phr, or even more than 5 phr) of carbon black, and that these compositions of the present invention do not necessarily contain silica, and may optionally contain at most 70 phr of unreinforced inorganic fillers such as chalk or aluminosilicates such as kaolin.

[0023] Similarly, advantageously, the crosslinkable composition may have a scorch resistance measured in accordance with standard ISO 289-2 at times t5 and t35 without early crosslinking of the composition, where both times t5 and t35 are greater than 17 minutes and more advantageously greater than 20 minutes, and times t5 and t35 correspond to Mooney viscosity increments of +5 and +35 points, respectively, at 125°C relative to the initial Mooney viscosity ML(1+4).

[0024] It should be noted that these times t5 and t35 are much higher than those of the control composition filled with carbon black.

[0025] According to one embodiment of the present invention, the crosslinking system comprises sulfur and optionally hydrogen peroxide, and the at least one elastomer is For example, ethylene-propylene (EPM) copolymers and ethylene-propylene-diene (EPDM) terpolymers, and ethylene-α-olefin copolymers. It is either functionalized or non-functionalized. Olefin-based rubber, and From conjugated diene monomers such as natural rubber (NR), isoprene homopolymers and copolymers, and butadiene homopolymers and copolymers, at least partially obtained, It is either functionalized or non-functionalized. Diene rubber, and other types of rubber selected from, The thermoplastic polymer phase comprises at least one saturated polymer (preferably selected from functionalized or unfunctionalized aliphatic or aromatic polyolefins, such as homopolymers or copolymers of ethylene or propylene).

[0026] It should be noted that this sulfur crosslinking system, in addition to sulfur, contains all or some of the usual vulcanization activators and accelerators, in known manner.

[0027] Ethylene-α-olefin copolymers for olefinic rubbers may generally be made from ethylene and α-olefins having 3 to 20 carbon atoms, preferably 3 to 12 carbon atoms (e.g., propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, and 1-dodecene). α-olefins selected from propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene are preferred.

[0028] Copolymers of isoprene and butadiene for diene rubber may be made from, for example, isoprene-butadiene (BIR) copolymers, and copolymers of isoprene and / or butadiene with vinyl aromatic comonomers such as styrene (SIR, SBR, SBIR).

[0029] According to one example of this embodiment, the at least one elastomer is EPDM having a mass content of ethylene-derived units of 15% to 80%, and the thermoplastic polymer phase comprises at least one aliphatic polyolefin selected from ethylene homopolymer, propylene homopolymer, and polypropylene-ethylene-diene polymer having a mass content of ethylene-derived units of 1% to 15%.

[0030] Therefore, it should be noted that the EPDM usable as an elastomer in the composition of the present invention may have a relatively high mass content of ethylene-derived units, with 60% to 80%, or conversely, a mass content of 15% to 20%. With respect to the aliphatic polyolefin forming the thermoplastic phase of the present invention, this may be "PEDM" mainly derived from polypropylene, with a mass content of at least 80% (e.g., 5% to 15% ethylene and 2.5% to 5% diene).

[0031] According to another embodiment of the present invention, the crosslinking system comprises a peroxide and optionally sulfur, the at least one elastomer is saturated, the thermoplastic polymer phase comprises saturated or unsaturated polymer chains, preferably the at least one elastomer is a silicone rubber selected from, for example, polydimethylsiloxane (PDMS), and the thermoplastic polymer phase comprises at least one saturated polymer selected from, for example, phenyl silicone or alkyl silicone resin.

[0032] It should be noted that this peroxide crosslinking system may advantageously contain an organic peroxide as a crosslinking agent and a crosslinking agent including, for example, triallyl cyanurate (TAC) or triallyl isocyanurate (TAIC).

[0033] Any polyorganosiloxane can be used as the silicone rubber, and any thermoplastic silicone resin, such as alkyl (e.g., methyl) silicone or phenyl silicone type, can be used as the saturated polymer.

[0034] Generally, the crosslinkable composition of the present invention may contain the thermoplastic polymer phase in an amount of 1 to 150 phr (phr: parts by weight per 100 parts by weight of elastomer), preferably 5 to 70 phr (more preferably 15 to 50 phr), and the nodules formed by the thermoplastic polymer phase have the weight-average maximum transverse dimension of 150 nm to 3 μm, preferably 300 nm to 2 μm.

[0035] According to another general aspect of the present invention, the nodule may, for example, be spherical or ellipsoidal.

[0036] The crosslinked rubber composition according to the present invention is a product of thermal crosslinking of the crosslinkable composition as defined above by a chemical reaction with the crosslinking system.

[0037] It should be noted that this crosslinking of the crosslinkable composition may be obtained, for example, by heating at 140-220°C, preferably 160-200°C.

[0038] According to another feature of the present invention, the crosslinked composition may contain, as a powder filler dispersed in the at least one elastomer, 0 to 100 phr (preferably 0 to 50 phr, more preferably 0 to 10 phr, or even more preferably 0 to 5 phr) of an organic filler such as carbon black and 0 to 70 phr (e.g., 10 to 60 phr) of an inorganic filler other than silica (chalk, or an aluminosilicate such as kaolin, etc.), and preferably the crosslinked composition does not contain any of the organic or inorganic powder fillers.

[0039] Advantageously, the crosslinked composition may have the following:

[0040] Densities less than -1.10, more favorably, 1 or less, and / or; -Measured in accordance with standard IEC 62631 3-1, 10 10 Exceeding Ω·cm, and to be even more advantageous, 10 14 Volume resistivity exceeding Ω·cm Therefore, it should be noted that when all embodiments and examples are combined, the density of the crosslinked composition according to the present invention is significantly reduced (favorably by more than 10% or more than 15%) compared to a control composition based on the same components (e.g., the same elastomer matrix and crosslinking system) but filled with carbon black instead of the thermoplastic phase.

[0041] Furthermore, it should be noted that when all embodiments and examples are combined, the electrical resistivity of the crosslinked composition according to the present invention increases significantly compared to this control composition filled with carbon black.

[0042] Similarly, advantageously, the crosslinked compositions according to the present invention (including all embodiments and examples) have a Shore A hardness and complex shear modulus G measured in accordance with the standard ASTM D2240. * The ratio of the storage modulus G' to the coefficient of elasticity is G'0.5% / G'20%, and the following conditions (i) and (ii) are met at 100°C: (i) G'0.5% / G'20% is 1.50 or less if the Shore A hardness is 40 to 50, 1.80 or less if the Shore A hardness is 51 to 60, and 2.00 or less if the Shore A hardness is 51 to 60; (ii) The tan delta at 0.5% strain is 0.080 or less, preferably 0.050 or less; At least one of the following conditions is met, where G'0.5% and G'20% are measured at dynamic strain amplitudes of 0.5% and 20% on a double shear specimen bridged at 177°C, subjected to a shear strain sweep of 0.5% to 60% at the same frequency of 1.7 Hz and the same temperature of 100°C, and tan delta represents the loss coefficient measured during the strain sweep.

[0043] These conditions are based on the same components (e.g., the same elastomeric matrix and crosslinking system), but it should be noted that the crosslinked compositions of the present invention exhibit a significantly reduced Payne effect and hysteresis loss compared to the corresponding control compositions filled with carbon black instead of the thermoplastic phase.

[0044] According to one embodiment presented above, wherein the at least one elastomer comprises an olefinic rubber such as EPM or EPDM, and the thermoplastic polymer phase comprises the at least one aliphatic polyolefin, the crosslinked composition has a Shore A hardness measured in accordance with standard ASTM D2240, as well as a ratio G'30Hz / G'0.3Hz of the storage modulus G' to the loss modulus tan delta, and at 100 °C under the following conditions (i) and (ii): * having a ratio G'30Hz / G'0.3Hz of the storage modulus G' to the loss modulus tan delta, and at 100 °C under the following conditions (i) and (ii): (i) G'30Hz / G'0.3Hz is 1.20 or less when the Shore A hardness is 51 - 60, and 1.10 or less when the Shore A hardness is 61 - 70; (ii) tan delta at 3 Hz is 0.80 or less when the Shore A hardness is 51 - 60, and 0.10 or less when the Shore A hardness is 61 - 70; where G'30Hz and G'0.3Hz are measured on a double shear specimen crosslinked at 177 °C with a dynamic strain amplitude of 0.5%, subjected to a frequency sweep from 0.100 Hz to 30000 Hz at the same temperature of 100 °C, and tan delta is measured at 3 Hz during the frequency sweep.

[0045] According to embodiments of the present invention, the crosslinked composition has a Shore A hardness measured according to standard ASTM D2240, and a loss factor tanD at 155Hz / M15Hz and 15Hz measured at 23°C via frequency sweep according to standard ISO 4664 by a Metravib® viscosity analyzer on a Metravib® block specimen, and the following conditions (i) and (ii): (i) M155Hz / M15Hz is 1.50 or less if the Shore A hardness is 40-50, and 2.00 or less if the Shore A hardness is 61-70; (ii) The tanD at 15 Hz is 0.10 or less when the Shore A hardness is 40-50, 0.15 or less when the Shore A hardness is 51-60, and 0.20 or less when the Shore A hardness is 61-70; It is possible that at least one of the following conditions is met.

[0046] Similarly, according to this embodiment, in which at least one elastomer comprises the olefin rubber such as EPM or EPDM, and the thermoplastic polymer phase comprises at least one aliphatic polyolefin, the crosslinked compound may satisfy one or more of the following conditions (i) to (iii): (i) The elongation at the breaking point, measured under uniaxial tension in accordance with standard ASTM D 412, is greater than 250%, preferably greater than 400%; (ii) The fracture stress measured by uniaxial tension in accordance with standard ASTM D 412 exceeds 4 MPa, preferably exceeding 12 MPa; (iii) The Shore A hardness measured after 3 seconds in accordance with standard ASTM D2240 is greater than 40, preferably 60 or higher.

[0047] It should be noted that these conditions, while based on the same components (e.g., the same elastomer matrix and crosslinking system), exhibit at least maintained, if not improved, reinforcing and static mechanical properties compared to the corresponding control composition filled with UV carbon black instead of the aliphatic polyolefin.

[0048] Furthermore, it should be noted that the applicant has demonstrated that these reinforcing and static properties are not substantially disadvantaged after thermal oxidative aging (i.e., under hot air) or aging by exposure to UV irradiation.

[0049] According to another embodiment of the present invention presented above, in which the at least one elastomer comprises the silicone rubber (preferably selected from polydimethylsiloxane (PDMS)) and the thermoplastic polymer phase comprises the at least one saturated polymer (preferably selected from phenyl or alkyl silicone resin), the crosslinked composition does not have to contain the powder filler such as silica at all.

[0050] Surprisingly, it should be noted that the absence of silica in such silicone rubber-based rubber compositions (which typically contain silica as a reinforcing filler) does not result in the increased reinforcing degree obtained by the dispersion of phenyl or alkyl silicone resin nodules, which is not accompanied by the mechanical nonlinearity observed under dynamic stress. This favorably demonstrates the similarly reduced Payne effect in this embodiment compared to a control composition based on the same components (e.g., the same elastomer matrix and crosslinking system) but filled with carbon black instead of this resin.

[0051] Similarly, according to the embodiment in which the at least one elastomer comprises the diene rubber at least partially derived from a conjugated diene monomer such as natural rubber, and the thermoplastic polymer phase comprises the at least one aliphatic polyolefin, the crosslinked compound may satisfy one or more of the following conditions (i) to (iii): (i) For the secant moduli M100, M200, and M300 measured under uniaxial tension in accordance with standard ASTM D 412 at 100%, 200%, and 300% strain, respectively, at least one of the following must be satisfied: M100 is greater than 3 MPa, preferably 5 MPa or more; M200 is greater than 6 MPa, preferably 8 MPa or higher; M300 is greater than 11 MPa, preferably 13 MPa or higher; (ii) The fracture stress measured by uniaxial tension in accordance with standard ASTM D 412 exceeds 13 MPa, preferably exceeding 18 MPa; (iii) The Shore A hardness measured after 3 seconds in accordance with standard ASTM D2240 is greater than 45, preferably 60 or higher.

[0052] It should be noted that these conditions, while based on the same components (e.g., the same elastomer matrix and crosslinking system), exhibit at least maintained, if not improved, reinforcing and static mechanical properties compared to a corresponding control composition filled with carbon black instead of the aliphatic polyolefin.

[0053] Furthermore, it should be noted that the applicant has demonstrated that these reinforcing and static properties are not substantially disadvantaged after thermal oxidative aging (i.e., under hot air) or aging by exposure to UV irradiation.

[0054] The mechanical member having a dynamic function according to the present invention is particularly selected from vibration-resistant supports and elastic joints for electric vehicles or industrial devices, the member being composed of a crosslinked rubber composition and including at least one elastic portion suitable for receiving dynamic stress, the crosslinked composition being as defined above according to the present invention.

[0055] The sealing elements according to the present invention are particularly selected from seals for vehicle bodies and seal profiles for buildings, and the sealing elements include an elastic portion made of a crosslinked rubber composition, and according to the present invention, the crosslinked rubber composition is as defined above.

[0056] In this case, for example, in a seal that guarantees leak prevention in the body of an automobile, it should be noted that the composition according to the present invention can be incorporated by bonding at most 100 phr of carbon black and 10 to 60 phr of an inorganic filler other than silica (e.g., aluminosilicate such as chalk or kaolin) to a metal oxide such as calcium oxide.

[0057] The method according to the present invention for preparing a crosslinkable composition as defined above comprises the following steps: a) A step of introducing at least one elastomer, then the other components excluding the crosslinking system, into an internal mixer such as a tangential or meshing (i.e., meshing rotor) internal mixer, or a screw extruder (e.g., a twin-screw extruder); b) A step of performing thermomechanical processing in the internal mixer or the screw extruder, wherein the reaction mixture is melt-blended with the crosslinking system removed to obtain a precursor mixture of a crosslinkable composition; c) Removing the mixture from the internal mixer or the screw extruder, and optionally cooling the mixture; d) A step of mechanically processing the precursor mixture at a temperature of, for example, 20 to 50°C, to obtain a crosslinkable composition, to which the crosslinking system containing sulfur and / or hydrogen peroxide has been added in advance; The above step (b) includes, b1) A step of heating the reaction mixture to the maximum blending temperature Ta, which is higher than the maximum melting point Tm of the thermoplastic polymer phase, preferably by a difference of Ta-Tm between 1 and 50°C, and b2) Stabilizing the heating at the maximum blending temperature Ta for at least 10 seconds during the holding time, wherein the holding time is preferably 20 seconds to 10 minutes. Includes.

[0058] Preferably, the difference between Ta and Tm is 5 to 30°C, and more preferably 10 to 20°C.

[0059] It should be noted that the value of Ta selected also depends on the value of Tm that characterizes the thermoplastic polymer phase used. If the thermoplastic polymer phase is based on an aliphatic polyolefin such as polypropylene, Ta may be, for example, 160 to 220°C, preferably 170 to 200°C. On the other hand, if the thermoplastic phase is an alkyl silicone resin or a phenyl silicone resin, Ta may be, for example, 70 to 150°C, preferably 80 to 120°C.

[0060] Similarly, Ta is preferably maintained for 30 seconds to 8 minutes, and more preferably for 1 to 5 minutes.

[0061] Advantageously, the heating in step b) in the internal mixer: For example, the rotor blades in the internal mixer are operated at a speed of 10-200 rpm, preferably 50-120 rpm, for at least 80 seconds. -1 Preferably at least 150s -1 The shear rate of the reaction mixture in the internal mixer; and / or jackets within an internal mixer that receive heat transfer fluid; To use Furthermore / or employing an internal mixer filling degree exceeding 100%, Executed by; Alternatively, in the case of the screw extruder, this is carried out by using a heating element (for example, an electric heating element) equipped in the extruder.

[0062] Such shear rates (e.g., 100-200 s) -1 It should be noted that this can be used in tangential internal mixers (e.g., Banbury type) or meshing internal mixers (e.g., Haake type).

[0063] It should also be noted that a rotation speed of 200 rpm can be used specifically for the Haake mixer, while a rotation speed of approximately 100 rpm can be used instead for the 3.6L Shaw mixer.

[0064] It should also be noted that in the operation of steps a) and b) in a screw extruder (e.g., a "ZSE 27 MAXX" twin-screw extruder manufactured by Leistritz), a maximum blending temperature Ta of at least 200°C is achieved via the electric heating element provided by the extruder during the heating of the mixture based on EPDM and aliphatic polyolefin (e.g., polypropylene), and this temperature Ta may be maintained for, for example, more than 30 seconds.

[0065] Other features, advantages, and details of the present invention are given in conjunction with the accompanying drawings as examples rather than limitations and will become apparent by reading the following description of some exemplary embodiments of the present invention. [Brief explanation of the drawing]

[0066] [Figure 1] This is a scanning electron microscope (SEM) image of the crosslinked composition I1 according to the present invention, which is based on an EPDM-type elastomer matrix. [Figure 2] This is an SEM image of another crosslinked composition I2 according to the present invention, based on the same EPDM-type elastomer matrix. [Figure 3] This is an SEM image of another crosslinked composition I3 according to the present invention, based on the same EPDM-type elastomer matrix. [Figure 4] This is an SEM image of another crosslinked composition I4 according to the present invention, based on the same EPDM-type elastomer matrix. [Figure 5]This is an SEM image of another crosslinked composition I5 according to the present invention, based on the same EPDM-type elastomer matrix. [Figure 6] This is an SEM image of another crosslinked composition I6 according to the present invention, based on the same EPDM-type elastomer matrix. [Figure 7] This is a stress-strain graph of the crosslinked compositions I1 to I6 according to the present invention. [Figure 8] This is an SEM image of another crosslinked composition I7 according to the present invention, based on a different EPDM-type elastomer matrix. [Figure 9] This is an SEM image of another crosslinked composition I8 according to the present invention, based on a different EPDM-type elastomer matrix. [Figure 10] This is an SEM image of another crosslinked composition I9 according to the present invention, based on a different EPDM-type elastomer matrix. [Figure 11] This is an SEM image of crosslinked control composition C1 based on a different EPDM-type elastomer matrix. [Figure 12] This is an SEM image of another crosslinked composition I10 according to the present invention, based on a different EPDM-type elastomer matrix. [Figure 13] This is an SEM image of another crosslinked composition I11 according to the present invention, based on a different EPDM-type elastomer matrix. [Figure 14] This is a stress-strain graph of the crosslinked compositions I17 to I11 according to the present invention. [Figure 15] This is an SEM image of another crosslinked composition I13 according to the present invention, based on an EPDM-type elastomer matrix. [Figure 16] This is an SEM image of another crosslinked composition I15 according to the present invention, based on an EPDM-type elastomer matrix. [Figure 17] This is an SEM image of another crosslinked composition I15' according to the present invention, based on an EPDM-type elastomer matrix. [Figure 18]This is a Shore A hardness-polypropylene (PP) content graph for crosslinked compositions I8, I12, I13, I14, I15, and I15' according to the present invention, based on an EPDM elastomer matrix. [Figure 19] This is a stress-strain graph of the crosslinked compositions I12 to I15' according to the present invention. [Figure 20] This is a stress-strain graph of another control composition C3 based on an EPDM elastomer matrix and a crosslinked composition I13 according to the present invention. [Figure 21] These are stress-strain graphs for the crosslinked composition I16 and another control composition C4 according to the present invention, both based on an EPDM elastomer matrix. [Figure 22] This bar graph shows the results of UV irradiation resistance tests for crosslinked composition I16 and control composition C4. [Figure 23] This is a Shore A hardness-polypropylene (PP) content graph for crosslinked compositions I19, I20, and I21 according to the present invention, based on a natural rubber (NR) elastomer matrix, as well as for control C7. [Figure 24] This is an SEM image of another crosslinked composition I26 according to the present invention, based on a different elastomer matrix made from silicone rubber. [Modes for carrying out the invention]

[0067] In the following examples, crosslinkable control compositions based on EPDM and filled with carbon black were prepared by performing the following sequential steps on a Haake® Polylab interlocking internal mixer.

[0068] filling: t=0 minutes Material: EPDM Speed: 50rpm T 調節 =40℃ Plasticization: t total =2 minutes material:- Speed: 50rpm T 調節 =40℃ filling: t total =4 minutes Materials: Filler + additives Speed: 50rpm T 調節 =40℃ Formula: t total =6 minutes material:- Speed: 50rpm T 自己発熱 =100℃ Discharge and cooling of the mixture: T 排出混合物 = 85℃ T 冷却混合物 =30℃ Acceleration at the mill: D day T=40℃ vulcanization: t=10 minutes T=177℃ Post-curing: t = 4 hours T=175℃ In the following examples, the crosslinkable composition of the present invention, based on EPDM and filled with polypropylene (PP) nodules, was prepared by performing the following sequential steps on a Haake® Polylab interlocking internal mixer.

[0069] filling: t=0 minutes Material: EPDM Speed: 5rpm T 調節 =80℃ Plasticization: t total =2 minutes material:- Speed: 200rpm T 調節 =80℃ filling: t total =4 minutes Material: PP+Oil Speed: 5rpm T 調節 =80℃ Formula: t total =11 minutes material:- Speed: 200rpm T 自己発熱 = 175℃ Stabilization of self-heating temperature: t+2 minutes 30 seconds material:- T 材料 = 175℃ T(°C): Function for rotational speed.

[0070] Discharge and cooling of the mixture: T 排出混合物 =160℃ T 冷却混合物 =30℃ Acceleration at the mill: D day T=40℃ vulcanization: t=t 95 T=180℃ In this process of the present invention, it should be noted that, following a conditioning temperature of 80°C, the examples of the EPDM matrix and PP dispersed phase use a self-exothermic temperature of 175°C, which is maintained for a stabilization time of 2 minutes and 30 seconds.

[0071] The standards and protocols for testing the resulting crosslinkable and crosslinked compositions are described below.

[0072] Measurement standards: MDR (Mobile Rheometer): ISO 6502: 2016 Shore A hardness: ASTM D 2240 Tension: ASTM D 412 Mooney viscosity: ISO 289-1 Scorch: ISO 289-2 Compression set: ISO815 Plot B Delft-type test specimen tear strength: ISO 34-2 UV resistance: PSA D27 1389 / ――G(2007) Volume resistivity: IEC 62631 3-1 SEM: A Zeiss scanning electron microscope (SEM / EDX) was used, combined with an X-ray photon detector (SEM / EDX) with a gold / palladium metal coating. Microscope settings are indicated in each photograph: (WD "Working Distance", EHT (electron high tension) "Accelerating Voltage", "Type 2·ES2" secondary electron detector, and aperture dimensions). Rubber Process Analyzer (RPA Rubber Process Analyzer): (Frequency sweep) 1. Bridge Temperature 177°C (+ / -0.5°C), frequency 0.002Hz, angle 0.5 degrees; 2. Frequency sweep Temperature 100.0℃, angle 0.5 degrees, frequency 0.100Hz, 0.300Hz, 1.000Hz, 3.000Hz, 10.000Hz, 30.000Hz; 5 points per condition.

[0073] (Strain sweep) 1. Bridge Temperature 177°C (+ / -0.5°C), frequency 1.7Hz, angle 0.5°; 2. Distortion sweep Temperature 100.0℃, frequency 1.7Hz, angles 0.5%, 0.7%, 1.0%, 2.0%, 4.0%, 6.0%, 8.0%, 10.0%, 20.0%, 40.0%, 60.0%; 5 points per condition.

[0074] Dynamic Mechanical Analysis (DMA) Test: The ISO 4664 standard applies to Metravib® viscosity analyzer testing as follows: Conditions: -10% ±0.1% at 155Hz, -10% ±2% at 15Hz Test specimen: Metravib(registered trademark) type block Number of test specimens: 3 per condition Measurement temperature: 23℃ Lubricant: Silicone oil spray.

[0075] The first series of tests on compositions having an EPDM matrix and a PP dispersed phase: EPDM was used that had a variable molar mass and a variable Mooney viscosity (ML(1+4) varied, for example, from 20 to 85), and similarly had variable mass contents of ethylene (C2), propylene (C3), dienes, and oils.

[0076] Table 1 below lists the formulations common to compositions I1, I2, I3, I4, I5, and I6 of the present invention.

[0077] [Table 1]

[0078] Table 2 below lists the essential conditions for the process of preparing crosslinkable compositions that distinguish compositions I1 to I6 (self-exothermic temperature and retention time).

[0079] [Table 2]

[0080] Regardless of the formulation conditions under these circumstances, all crosslinked compositions I1 to I6 exhibit a uniformly dispersed PP phase within the EPDM matrix. The particle sizes measured by SEM are shown in Table 3 below.

[0081] [Table 3]

[0082] The morphology and filler-matrix interactions of the crosslinked compositions I1-I6, as seen in Figures 1-6, allow for very good reinforcement, as demonstrated by tensile tests performed on the crosslinked compositions I1-I6 in accordance with standard ASTM D412, the results of which can be seen in Figure 7.

[0083] Table 4 below details the formulations common to compositions I7, I8, I9, I10, and I11 according to the present invention, as well as control composition C1.

[0084] [Table 4]

[0085] Table 5 below details the EPDM used as the elastomer matrix in compositions I7 to I11 and C1.

[0086] [Table 5]

[0087] Table 6 below provides comments on the forms of the crosslinked compositions I7-I11, which can be seen in Figures 8, 9, 10, 12, and 13, and the control composition C1, which can be seen in Figure 11.

[0088] [Table 6]

[0089] Apart from composition C1, which has a very high ethylene content (85%) in EPDM, the desired form can be obtained for dispersed nodules.

[0090] Promoting composition C1 on the mill has not been successful, and it has been identified that this very high content of ethylene in the EPDM of composition C1 appears to induce a bi-continuous form. Elastomer properties are lost in composition C1.

[0091] In the modular configurations obtained for compositions I7 to I11 of the present invention, a crosslinking system was added to an open mill, and then these compositions I7 to I11 were crosslinked. As can be seen from Figure 14, these compositions I7 to I11 have good mechanical properties, and in particular, reinforcing properties suitable for industrial applications.

[0092] Table 7 below details the properties obtained for these crosslinked compositions I7 to I11 according to the present invention.

[0093] [Table 7]

[0094] Table 8 below details the results obtained regarding the dynamic properties of composition I8 alone.

[0095] [Table 8]

[0096] Table 9 below details the formulation common to composition I8 and the other compositions I12, I13, I14, I15, and I15'.

[0097] [Table 9]

[0098] The results for the tested polypropylene PPH3060 are shown in Table 10 below.

[0099] [Table 10]

[0100] Compositions I8 and I12-I15' are as shown in Table 11 below.

[0101] [Table 11]

[0102] As shown in Figures 15-17, the obtained morphology was similar for all compositions I8 and I12-I15', and PP was dispersed in the EPDM matrix in the form of nodules of approximately 1 μm.

[0103] Table 12 below details the mechanical and effective reinforcing properties obtained for these crosslinked compositions I8 and I12-I15'. In particular, Figure 18 shows the change in Shore A hardness of these compositions with respect to PP content (phr).

[0104] [Table 12]

[0105] Figure 19 shows the satisfactory reinforcement properties obtained for these compositions I12 to I15'.

[0106] Table 13 below details the formulation of control composition C3 (having an EPDM matrix) and compares it with the formulation of composition I13 described above according to the present invention, showing that both compositions have the same Shore A hardness.

[0107] [Table 13]

[0108] As shown in Table 14 below, regarding the properties in the crosslinkable and crosslinked states, composition I13 exhibits an 18% decrease in density, an increase in scorch time, improved fracture properties, and a reduction in mechanical nonlinearity during strain sweep (Payne effect) and frequency sweep, compared to the control composition C3.

[0109] [Table 14]

[0110] Figure 20 compares the tensile curves of compositions I13 and C3, demonstrating the superior reinforcement of composition I13.

[0111] In Table 15 below, the dynamic properties of this same composition I13 are compared with the dynamic properties of another control composition C5, which is further based on an EPDM matrix.

[0112] [Table 15]

[0113] Table 16 below details these favorable dynamic properties of composition I13 as measured by Metravib (see in particular tanD and ratio M155 / M15Hz).

[0114] [Table 16]

[0115] Table 17 below details the formulations of another composition I16 according to the present invention, compared to control composition C4, which is further based on an EPDM matrix. These formulations are particularly suitable for automotive body seals, and compositions I16 and C4 have similar hardness.

[0116] [Table 17]

[0117] Composition I16 contains 5 phr of carbon black to ensure blackness and is representative during UV resistance testing. Due to the very high content of fillers (especially transparent fillers), no morphology could be observed.

[0118] As shown in Table 18 below, composition I16 yielded the following advantageous results compared to control composition C4: • Density decrease (-12%) • No scorching • Similar reinforcement (similar modulus of elasticity), but with significantly improved fracture strength. • Excellent mechanical properties after aging. • A reduction of 10-20 points in compression set. • Significant reduction in discoloration after UV aging of CI4000. • Very low conductivity.

[0119] [Table 18]

[0120] Figure 21 shows the superiority of composition I16 compared to C4 in terms of reinforcement, and Figure 22 shows its superiority in terms of UV resistance (tests were conducted in accordance with standard PSA D27 1389 / -G (2007)).

[0121] Table 19 below lists the data obtained after 5 cycles of UV exposure.

[0122] [Table 19]

[0123] A second series of tests on compositions having an NR matrix and a PP dispersed phase: Table 20 below details the formulations of two compositions I17 and I18 according to the present invention, compared to control composition C6. All are based on natural rubber as the elastomer matrix.

[0124] [Table 20]

[0125] As shown in Table 21 below, compositions I17 to I18 exhibit greater reinforcement, very high modulus of elasticity at low strain, and improved aging resistance compared to composition C6.

[0126] [Table 21]

[0127] Table 22 below details the formulations common to three other compositions based on NR, I19, I20, and I21, compared to one other control composition based on NR, C7.

[0128] [Table 22]

[0129] The mechanical properties obtained are detailed in Table 23 below.

[0130] [Table 23]

[0131] Table 23 shows that the level of reinforcement of compositions I19-I21 can be adjusted by changing the content of PP dispersed in NR, and Figure 23 shows the change in Shore A hardness of these compositions I19-I21 compared to composition C7.

[0132] A third series of tests relating to compositions having a silicone rubber matrix and a dispersed phase of phenylsilicone resin: Six compositions according to the present invention, I22, I23, I24, I25, I26, and I27, were tested in comparison with control composition C8. All of these are based on PDMS as silicone rubber and, with the exception of composition C8, contain dispersed phenylsilicone thermoplastic resin. Compositions I22-I27 contain the following: Momentive SilPlus70HS (polydimethylsiloxane) silicone rubber base, 100 phr.

[0133] • Phenyl resin with a softening point of 60-70°C (BELSIL® SPR 45 VP provided by Wacker) Hydrogen peroxide DBPH (2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane) 1 phr.

[0134] The forms obtained for these compositions I22 to I27 consisted of a PDMS matrix containing micrometer-level nodules of this resin (see the photograph in Figure 24 for composition I26 having 50 phr of resin).

[0135] As shown in Table 24 below, the PDMS matrices of compositions I22-I27 are sufficiently reinforced regardless of the resin concentration.

[0136] [Table 24]

[0137] As shown in Table 25 below, in relation to dynamic testing (DMA), the high level of reinforcement of composition I26, in contrast to conventional reinforcing fillers (silica in the case of silicone resins), advantageously does not result in mechanical nonlinearity (reduced Payne effect).

[0138] [Table 25]

Claims

1. A method for producing a crosslinked rubber composition based on at least one elastomer, The crosslinked rubber composition comprises a crosslinking system and other components including a thermoplastic polymer phase having at least one melting point Tm and dispersed in the at least one elastomer in the form of nodules. The nodule has a weight-average maximum transverse dimension of 10 nm to 10 μm. The crosslinking system contains sulfur when at least one elastomer is unsaturated and the thermoplastic polymer phase contains saturated polymer chains, and contains hydrogen peroxide when at least one elastomer is saturated. The crosslinked rubber composition comprises, as a powder filler dispersed in the at least one elastomer, 0 to 50 phr of an organic filler and 0 to 70 phr of an unreinforced inorganic filler other than silica, where phr represents parts by weight per 100 parts by weight of elastomer. (i) The crosslinking system comprises sulfur and optionally further hydrogen peroxide, the at least one elastomer is a rubber selected from functionalized or unfunctionalized olefin rubbers, and the thermoplastic polymer phase comprises at least one saturated polymer, (ii) The crosslinking system comprises hydrogen peroxide and optionally further sulfur, the at least one elastomer is saturated, the thermoplastic polymer phase comprises saturated or unsaturated polymer chains, the at least one elastomer is silicone rubber, and the thermoplastic polymer phase comprises at least one saturated polymer selected from phenyl silicone or alkyl silicone resins. The aforementioned method, A) A process for producing a crosslinkable composition, a) A step of introducing at least one elastomer, then the other components excluding the crosslinking system, into an internal mixer or screw extruder to obtain a reaction mixture; b) A step comprising performing thermomechanical processing by melting and blending the reaction mixture introduced in step a) in the internal mixer or the screw extruder to obtain a precursor mixture of a crosslinkable composition; c) a step of removing the mixture from the internal mixer or the screw extruder and optionally cooling the mixture; and, d) A step of adding the crosslinking system containing sulfur and / or hydrogen peroxide to the precursor mixture, and then mechanically processing the mixture resulting from the addition to obtain a crosslinkable composition; The above step b) includes, b1) A step of heating the reaction mixture to a mixing temperature Ta which is the maximum during thermomechanical processing and is higher than the melting point Tm of at least one of the thermoplastic polymer phases, and b2) A step of stabilizing the heating by maintaining the mixing temperature Ta for a holding time of 30 seconds to 8 minutes. Processes including, A method comprising the step of producing a crosslinked composition by thermal crosslinking the crosslinkable composition obtained in step d) of step A) with the crosslinking system through a chemical reaction.

2. The method according to claim 1, wherein the holding time at the blending temperature Ta is 1 minute to 5 minutes.

3. The method according to claim 1 or 2, wherein the powder filler dispersed in the at least one elastomer comprises 0 to 10 phr of the organic filler and 0 to 60 phr of the unreinforced inorganic filler other than silica.

4. The method according to any one of claims 1 to 3, wherein the crosslinkable composition has a scorch resistance measured in accordance with standard ISO 289-2 at times t5 and t35 without early crosslinking of the composition, both times t5 and t35 exceed 17 minutes, and times t5 and t35 are related to Mooney viscosity increments of +5 points and +35 points, respectively, at 125°C relative to the initial Mooney viscosity.

5. The at least one elastomer is EPDM having a mass content of ethylene-derived units of 15% to 80%, The method according to claim 1, wherein the thermoplastic polymer phase comprises at least one aliphatic polyolefin selected from ethylene homopolymer, propylene homopolymer, and polypropylene-ethylene-diene polymer having a mass content of ethylene-derived units of 1% to 15%.

6. The crosslinkable composition contains the thermoplastic polymer phase in an amount of 1 to 150 phr (phr: parts by weight per 100 parts by weight of elastomer), The nodule formed by the thermoplastic polymer phase has a weight-average maximum transverse dimension of 150 nm to 3 μm. The method according to any one of claims 1 to 5, wherein the nodule is spherical or elliptical.

7. In step b), the heating in the internal mixer is: At least 80s －１ The shear rate of the reaction mixture in the internal mixer; and / or jackets within an internal mixer that receive heat transfer fluid; To use Furthermore / or employing an internal mixer filling degree exceeding 100%, It is performed by; Alternatively, in the screw extruder, this is performed by using a heating element equipped in the extruder. The method according to any one of claims 1 to 6.

8. The crosslinked composition obtained in step B) has a density of less than 1.10, and / or The volume resistivity measured in accordance with standard IEC 62631 3-1 is 10 １０ The method according to any one of claims 1 to 7, wherein the result exceeds Ω·cm.

9. The crosslinked composition has a Shore A hardness and a complex shear modulus G measured in accordance with the ASTM D2240 standard. ＊ The ratio of the storage modulus G' to the storage modulus G' is G'0.5% / G'20%. At 100°C, under the following conditions (i) and (ii): (i) G'0.5% / G'20% is 1.50 or less if the Shore A hardness is 40 to 50, 1.80 or less if the Shore A hardness is 51 to 60, and 2.00 or less if the Shore A hardness is 51 to 60; (ii) The tan delta at 0.5% strain is 0.080 or less; Satisfying at least one of the following conditions, The method according to any one of claims 1 to 8, wherein G'0.5% and G'20% are measured at dynamic strain amplitudes of 0.5% and 20% on a double shear specimen bridged at 177°C, subjected to a shear strain sweep of 0.5% to 60% at the same frequency of 1.7 Hz and the same temperature of 100°C, and tan delta represents the loss coefficient measured during the strain sweep.

10. The at least one elastomer comprises an olefin-based rubber, and the thermoplastic polymer phase comprises at least one aliphatic polyolefin. The crosslinked composition has a Shore A hardness and complex shear modulus G measured in accordance with the ASTM D2240 standard. ＊ and the ratio of the storage modulus G' to the loss coefficient tan delta is G'30 Hz / G'0.3 Hz. At 100°C, under the following conditions (i) and (ii): (i) G'30Hz / G'0.3Hz is 1.20 or less when the Shore A hardness is 51-60, and 1.10 or less when the Shore A hardness is 61-70; (ii) The tan delta at 3 Hz is 0.80 or less when the Shore A hardness is 51 to 60, and 0.10 or less when the Shore A hardness is 61 to 70; Satisfying at least one of the following conditions, The method according to any one of claims 1 to 9, wherein G' 30 Hz and G' 0.3 Hz are measured at a dynamic strain amplitude of 0.5% on a double shear specimen bridged at 177°C, and undergo a frequency sweep from 0.100 Hz to 30000 Hz at the same temperature of 100°C, and the tan delta is measured at 3 Hz during the frequency sweep.

11. The at least one elastomer comprises an olefin-based rubber, The thermoplastic polymer phase comprises at least one aliphatic polyolefin, The method according to any one of claims 1 to 9, wherein the crosslinked composition has a Shore A hardness measured according to standard ASTM D2240, and a loss factor tanD at 15 Hz and a modulus of elasticity M155 Hz / M15 Hz measured at 23°C via frequency sweep according to standard ISO 4664 using a Metrovib® viscosity analyzer on a Metrovib® block specimen, and satisfies at least one of the following conditions (i) and (ii): (i) The M155Hz / M15Hz ratio is 1.50 or less when the Shore A hardness is 40-50, and 2.00 or less when the Shore A hardness is 61-70; (ii) The tanD at 15 Hz is 0.10 or less when the Shore A hardness is 40 to 50, 0.15 or less when the Shore A hardness is 51 to 60, and 0.20 or less when the Shore A hardness is 61 to 70.

12. The method according to any one of claims 1 to 11, wherein the at least one elastomer comprises an olefin-based rubber, the thermoplastic polymer phase comprises at least one aliphatic polyolefin, and the crosslinked composition satisfies at least one of the following conditions (i) to (iii): (i) The elongation at the breaking point, measured under uniaxial tension in accordance with standard ASTM D 412, exceeds 250%; (ii) The fracture stress measured by uniaxial tension in accordance with the ASTM D 412 standard exceeds 4 MPa; (iii) The Shore A hardness measured after 3 seconds in accordance with the ASTM D2240 standard exceeds 40.

13. The at least one elastomer comprises silicone rubber, and the thermoplastic polymer phase comprises at least one saturated polymer selected from phenyl silicone or alkyl silicone resin. The method according to any one of claims 1 to 4 or 6 to 9, wherein the crosslinked composition does not contain the powder filler at all.

14. The crosslinked rubber composition forms the elastic portion of a mechanical component having a dynamic function selected from vibration-resistant supports and elastic joints for electric vehicles or industrial equipment. The method according to any one of claims 1 to 13, wherein the elastic portion is suitable for being subjected to dynamic stress.

15. The method according to any one of claims 1 to 13, wherein the crosslinked rubber composition forms an elastic portion of a sealing element selected from vehicle body seals and building seal profiles.

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