Thermoplastic elastomer composition, process for its production and wear-resistant parts obtained therefrom.

Description

1 / 20 Thermoplastic elastomer composition, process for its production and wear-resistant parts obtained therefrom. FIELD OF THE INVENTION

[0001] The present invention relates to a thermoplastic elastomeric composition characterized by high wear resistance, to the production process of the composition and to parts produced with the composition, such as gloves, gaskets for washing machine doors, bellows and the like. STATE OF THE ART

[0002] Elastomeric parts are used in various applications where two rigid parts subject to relative movement need to be connected; this may be the case, for example, of fluid ducts (e.g., in engines or other vehicle parts), or joints that must be able to maintain their function (preventing fluid leakage, in particular water) through vibration of the parts between which they are positioned, as in the case of gaskets for washing machine doors.

[0003] These parts must exhibit a combination of properties, in particular hardness within a given range, chemical inertness, and retention of their mechanical properties within the operating temperature range of the intended application.

[0004] Furthermore, the compositions of these parts are thermoplastic, thus allowing the production of parts, often with relatively complex shapes, by injection molding or similar methods.

[0005] Thermoplastic elastomer compositions with specific sets of properties are known in the art.

[0006] Patent application EP 2123708 A1 describes a Petition 870250049788, dated 06 / 13 / 2025, page 21 / 50 2 / 20 composition for a gasket, including a hydrogenated styrene-based block copolymer and about 70 to 99 parts by weight of a petroleum-based softener, about 10 to 25 parts by weight of a polyolefin-based resin, about 10 to 25 parts by weight of an inorganic filler and about 10 to 25 parts by weight of a heat-resistant polymer, the weight parts of the components mentioned being based on 100 parts by weight of the hydrogenated styrene-based block copolymer. The composition of this document is considered to have good tensile and heat resistance.

[0007] Patent EP 2196500 B1 describes thermoplastic elastomer compositions comprising 25 to 55 parts by weight of a block terpolymer, including an aromatic vinyl compound and an alkene compound; 20 to 50 parts by weight of a paraffin oil; 5 to 15 parts by weight of a polyolefin resin; 5 to 20 parts by weight of an inorganic additive; and 3 to 15 parts by weight of a polyphenylene ether. The declared properties of the composition in this document are surface hardness and high temperature resistance.

[0008] Patent EP 2792710 B1 describes a thermoplastic elastomer composition comprising (by weight) 30 to 40% of a block terpolymer of an aromatic vinyl alkene compound or a conjugated diene-based compound; 25 to 50% of a paraffin oil; 1 to 5% of a polyolefin-based resin; 5 to 20% of an inorganic additive; and 5 to 15% of a polyphenylene ether-based resin. Among the stated advantages of this composition are a surface hardness of 0.1 to 40 Å (shore A) and high temperature resistance.

[0009] Finally, the international patent application WO Petition 870250049788, dated 06 / 13 / 2025, p. 22 / 50 3 / 20 2012 / 091230 A1 describes a thermoplastic elastomer comprising (by weight): 25 to 55% of a hydrogenated triblock copolymer; 20 to 50% of a non-aromatic oil; 5 to 15% of a polyolefin resin; 5 to 20% of an inorganic filler; 3 to 15% of a polyphenylene ether-based resin; and 0.01 to 0.5% of a silicone resin; optionally, the composition may further comprise between 0.1 and 3 parts by weight of a metal or metal oxide per 100 parts by weight of the sum of the other components. The non-aromatic oil is considered to be a paraffinic oil, or a mixture, possibly with a naphthenic oil, including at least 50% by weight, preferably at least 65% by weight, of a paraffinic oil; All examples refer to compositions prepared with 100% paraffin oil as the non-aromatic oil. The inventors declare that these elastomers exhibit low hardness, high strength, high surface hardness, and abrasion resistance.

[0010] Despite the good properties declared of the compositions mentioned above, these are still not sufficient for recent devices, particularly those in which the elastomeric part has highly convoluted cross-sections, suitable, for example, for application in small washing machines. In a test campaign, the present inventors prepared bellows with a very compact shape, repeating the recipes and reproducing the compositions of the prior art; when subjected to abrasion tests, the bellows thus produced showed unsatisfactory results, leading to breakage of the bellows before reaching 50,000 friction cycles. The known compositions, therefore, are not suitable for easy shaping by injection molding into highly convoluted shapes. Petition 870250049788, dated 06 / 13 / 2025, page 23 / 50 4 / 20 elaborated; furthermore, the compositions of the prior art do not exhibit the necessary wear resistance due to friction between the different sections of the elastomeric part, leading to failure (formation of fractures) after a number of vibration cycles lower than the desired service life of the device.

[0011] It is therefore an object of the present invention to provide a thermoplastic elastomeric composition characterized by easy formability and high wear resistance, a process for producing the composition, as well as elastomeric parts produced with the composition. SUMMARY OF THE INVENTION

[0012] These objects are obtained with the present invention which, in a first aspect, refers to a thermoplastic elastomeric composition comprising the following components: (A) between 10 and 24% by weight of a hydrogenated triblock copolymer; (B) between 30 and 60% by weight of a naphthenic oil; (C) between 2 and 20% by weight of a polyolefin resin; (D) between 4 and 20% by weight of a polyphenylene ether; (E) between 2 and 20% by weight of a load; (F) between 0.1 and 8% by weight of a liquid silicone oil; (G) between 0.1 and 8% by weight of one or more components selected from amides, silicone resins and polyurethanes.

[0013] The compositions of the invention may optionally comprise up to 5% of one or more other additives, cumulatively referred to in the description as component (H). Petition 870250049788, dated 06 / 13 / 2025, page 24 / 50 5 / 20

[0014] In its second aspect, the invention relates to a process for producing a composition as defined above, comprising feeding an extruder with the solid components of the composition, partly through a main hopper at the beginning of the extruder and partly through one or two side dosing stations (side feeders), and injecting the liquid components into the extruder at one or more feed ports between the beginning of the extruder and half its length, maintaining the extruder temperature profile between 160 and 240 °C. The composition exiting the extruder head is preferably cut into pellets using a head cutting and cooling system.

[0015] In its third aspect, the invention relates to an elastomeric part produced with the composition described above. BRIEF DESCRIPTION OF THE FIGURES

[0016] Fig. 1 is a drawing that reproduces an apparatus for carrying out tests of the durability of samples of the invention to abrasion cycles;

[0017] Fig. 2 is a graph showing the results of dynamometric tests performed on samples of the invention's composition. DETAILED DESCRIPTION OF THE INVENTION

[0018] In the following description, the quantities of components (A) to (G) and of the optional component (H), which make up the compositions of the invention, are given in terms of weight percentage (abbreviated as % by weight), unless otherwise specified.

[0019] In its first aspect, the present invention relates to a thermoplastic elastomeric composition that has proven particularly easy to shape by injection molding and that allows the production of molded articles with very high Petition 870250049788, dated 06 / 13 / 2025, p. 25 / 50 6 / 20 abrasion resistance.

[0020] The first component, (A), of the compositions of the invention, is a hydrogenated triblock copolymer.

[0021] Hydrogenated triblock copolymers useful for the purposes of the invention are styrene-ethylene-propylene-styrene (referred to in the field by the acronym SEPS), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-isoprene-butadiene-styrene (SIBS), styrene-ethylene / propylene block copolymer (SEP), styrene-ethylene / (ethylene / propylene)-styrene (SEEPS) and, preferably, styrene-ethylene-butadiene-styrene (SEBS). The hydrogenated triblock copolymer must have a melt flow index < 6 (measured according to ASTM D 1238, g / 10 min, 200 °C, 5 kg) and a styrene content between 10 and 35% by weight.

[0022] The hydrogenated triblock copolymer is present in the compositions of the invention in an amount between 10 and 24% by weight, preferably between 18 and 23% by weight, of the total weight of the composition.

[0023] In a preferred embodiment, the hydrogenated triblock copolymer employed in the compositions of the invention has a very high molecular weight, such that a 5 wt% solution of the polymer in toluene has a viscosity of at least 350 cP when measured at 25 °C following the procedure of ASTM D2196-20 Method A.

[0024] The second component, (B), of the compositions of the invention, is a naphthenic oil, in an amount between 30 and 60% by weight, and preferably between 38 and 45% by weight, of the total weight of the composition.

[0025] Naphthenic oil is a complex mixture of hydrocarbons obtained by treating a fraction of Petition 870250049788, dated 06 / 13 / 2025, page 26 / 50 7 / 20 petroleum with hydrogen in the presence of a catalyst. It consists of hydrocarbons having carbon numbers primarily in the range of C20 to C50, with a relatively low amount of paraffins, and is identified by the CAS number 64742-52-5.

[0026] The amount of naphthenic oil in the compositions of the invention is relatively high. Known compositions, designed for applications similar to those of the present invention, generally contain paraffinic oils as softeners.The use of a naphthenic oil as a softener was foreseen in the compositions disclosed in patent application EP 2123708 A1; however, this document describes compositions in which the softener (which may be a naphthenic or paraffinic oil) is present in amounts between about 70 and 99 parts by weight per 100 parts by weight of a hydrogenated styrene-based block copolymer, i.e., a softener:copolymer weight ratio of less than 1; The document also reports, at the end of paragraph

[0018] , that when the softener content exceeds 99 parts by weight (i.e., a softener:copolymer weight ratio greater than 0.99), the composition becomes viscous due to oil exudation, is easily contaminated and hardens with aging in operation, and is therefore unsuitable as a material for the production of gaskets.The present inventors have surprisingly discovered that, with the specific compositions of the invention, in which the softener:copolymer weight ratio is between 1.25 and 6, and comprising the other components specified above, such disadvantages are not observed and the articles produced with these compositions exhibit the useful properties mentioned above.

[0027] Naphthenic oils useful for the purposes of Petition 870250049788, dated 06 / 13 / 2025, page 27 / 50 8 / 20 The invention exhibits a kinematic viscosity according to ASTM D 445 in the range of 50 to 100 mm² / s, preferably between 50 and 90 mm² / s, at 40 °C. Oils with these characteristics are commercially available and are sold, for example, by Oleotecnica SpA of Segrate (Milan), Italy, under the brand name NYSOL.

[0028] Component (C) of the invention's compositions is a polyolefin resin. This component is present in the invention's compositions in an amount between 2 and 20% by weight, preferably between 5 and 15% by weight. The polyolefin is preferably polypropylene (PP), ethylene-propylene copolymer (EP), polyethylene (PE), thermoplastic polyolefins (TPO) and mixtures thereof. The Melt Flow Index (MFI) of the polyolefin is < 10 g / 10 min, as measured according to ISO 1133 (2.16 kg, 230 °C).

[0029] Component (D) of the compositions of the invention is a polyphenylene ether, with a minimum purity of 99%, which is present in the compositions in an amount between 5% and 20% by weight, preferably between 7% and 15% by weight. Examples of polyphenylene ether resins useful for the purposes of the invention are poly(2,6-dimethyl-1,4-phenylene ether), poly(2,6-diethyl-1,4-phenylene ether), poly(2,6-dipropyl-1,4-phenylene ether), poly(2-methyl-6-ethyl-1,4-phenylene ether), poly(2-methyl-6-propyl-1,4-phenylene ether), poly(2-ethyl-6-propyl-1,4-phenylene ether), poly(2,6-diphenyl-1,4-phenylene ether), copolymers of poly(2,6-dimethyl-1,4-phenylene ether) and poly(2,3,6-trimethyl-1,4-phenylene ether), copolymers of poly(2,6-dimethyl-1,4-phenylene ether) and ether of poly(2,3,6-triethyl-1,4-phenylene), and the like, and combinations thereof. A preferred polyphenylene ether for the purposes of the invention is poly(2,6-dimethyl) ether. Petition 870250049788, dated 06 / 13 / 2025, page 28 / 50 9 / 20 1,4-phenylene), having molecular formula (C8H8O)n, alone or as a copolymer with poly(2,3,6-trimethyl-1,4-phenylene) ether, having formula (C9H10O)n. The polyphenylene ether resin may have a weight-average molecular weight of about 20,000 to about 60,000 g / mol, for example, about 22,000 to about 40,000 g / mol, an apparent density between 350 and 550 kg / dm3, measured according to ISO 1183, and a degree of polymerization corresponding to an intrinsic viscosity of about 0.2 to about 0.8 dL / g, measured in chloroform as solvent at 25 °C.

[0030] Component (E) is a filler and is present in the compositions in an amount between 2 and 20% by weight, preferably between 8 and 14% by weight. The filler is employed in the form of powders with a particle size between 0.01 and 5 μm. Preferably, the filler is an inorganic material, such as talc, clay, calcium carbonate, silica, kaolin, calcined kaolin, iron oxide, glass fibers, mica, titanium dioxide, carbon black, graphite, wollastonite or mixtures thereof; the filler is preferably talc and, more preferably, calcium carbonate.

[0031] Component (F) is a liquid silicone oil and is present in the compositions in an amount between 1 and 8% by weight, preferably between 3 and 6% by weight. This component is a liquid (therefore, not a silicone gum or resin) having a viscosity between 40 and 150 mm2 / s, measured according to ASTM D445.

[0032] Finally, component (G) of the compositions of the invention is one or more compounds selected from amides (including oleamide, erucamide and so forth), silicone resins (including ultra-high molecular weight silicone) Petition 870250049788, dated 06 / 13 / 2025, p. 29 / 50 10 / 20 with a molecular weight close to 300,000 g / mol and high molecular weight silicon (with a lower molecular weight, but available as a solid material) and polyurethanes (PU, polyester-based TPU and polyether-based TPU); these compounds have a synergistic effect with the liquid silicone oil, conferring excellent wear resistance to the final thermoplastic elastomer. This component (one or a mixture of the aforementioned compounds) is present in the compositions of the invention in amounts between 0.1 and 5%, preferably between 0.1 and 2% by weight.

[0033] The compositions of the invention may optionally comprise up to 5% of one or more other additives, cumulatively referred to in the description as component (H). This component may be one or a mixture of additives known in the field, such as boosting agents, flame retardants, antimicrobial agents, UV blocking agents, hindered amine light stabilizers, antioxidants, etc.

[0034] Compared to the compositions of the prior art, those of the present invention have a relatively lower content of hydrogenated triblock copolymers (component (A)): this allows for higher weight percentages of the remaining components, in particular polyphenylene ether (component (D)) and the sum of components (F) and (G). These differences in composition allow for the production of parts with excellent physical and mechanical properties. In particular, these parts exhibit Shore A hardness in the range of 25 to 75, measured according to ISO 868 A (3 seconds of force application on the presser foot), a permanent compression set, measured according to ISO 815, of less than 80% with compression at 100 °C for 72 h and less than 45% with compression at 23 °C for 22 h. Petition 870250049788, dated 06 / 13 / 2025, page 30 / 50 11 / 20

[0035] Furthermore, the compositions of the invention exhibit much greater abrasion resistance than similar compositions of the prior art: the inventors observed that, in abrasion tests carried out as described in the experimental part, parts produced with the compositions of the invention typically withstand at least 500,000 abrasion cycles at 23 °C, compared with less than 50,000 cycles for a prior art composition, and at least 15,000 abrasion cycles at 75 °C, compared with less than 5,000 cycles for a prior art composition.

[0036] In its second aspect, the invention relates to a process for producing a thermoplastic elastomeric composition described above.

[0037] The compositions described above can be produced using commercial mixers, preferably with twin-screw extruders, more preferably with co-rotating twin-screw extruders.

[0038] The high weight ratio of naphthenic oil / hydrogenated triblock copolymer according to the invention, at least equal to 1.25, allows processability with twin-screw extruders, even using hydrogenated block copolymers with very high viscosities, for example, those with a measured melt flow index < 1 at 200 °C (5 kg load) according to ASTM D 1238; in turn, the high viscosity of the triblock copolymer implies a high molecular weight and therefore the ability to retain the plasticizer, preventing exudation. The silicone oil of the compositions of the invention gives the surface of the parts thus produced a wet appearance, which, however, is not related to phenomena of release of liquid components. Petition 870250049788, dated 06 / 13 / 2025, page 31 / 50 12 / 20 of the aforementioned parts. This combination of characteristics makes it possible to obtain articles that maintain their mechanical properties over time, avoiding hardening that could lead to their failure.

[0039] Solid components are introduced partly into a main loading hopper at the beginning of the extruder and partly through one or two side dosing stations (side feeders), while liquid components are injected into the extruder at one or more feed ports between the beginning of the extruder and half of its length.

[0040] The loading of the components occurs through the use of gravimetric dosers of individual components or pre-weighed mixtures thereof; it would also be possible to use volumetric dosers if these were precisely synchronized; gravimetric dosers are preferred due to the ease of maintaining the desired weight ratio between the different components.

[0041] The temperature profile of the extruder varies depending on the specific composition; generally, this temperature is between 160 and 240 °C.

[0042] The composition that comes out of the extruder head is then preferably cut into small pellets using the classic head cutting and cooling system.

[0043] In its third aspect, the invention relates to manufactured articles obtained with the compositions described above. These compositions have proven to be particularly suitable for shaping parts with complex and convoluted shapes by injection molding. The elastomeric parts that can be produced with the compositions of the invention are bellows and, in particular, gaskets for machine doors. Petition 870250049788, dated 06 / 13 / 2025, page 32 / 50 13 / 20 wash.

[0044] The invention will be described in more detail by the following examples.

[0045] The following instruments and materials were used in the experiments: - Twin-screw extruder, size 71 mm, 56 mm L / D, manufactured by ICMA San Giorgio SpA of San Giorgio su Legnano (Milan), Italy; - apparatus for carrying out abrasion tests installed in the applicant's laboratories, schematically illustrated in Fig. 1 and described in detail below; - component (A), hydrogenated triblock copolymer: SEBS, Europrene® SOL TH 2315 from Versalis; - component (B), naphthenic oil: Nysol N85 and Tecnol 100 paraffin oil from Oleotecnica SpA, Segrate (Milan), Italy; - component (C), polyolefin resins: EP (Tipplen® K 499 from MOL Petrochemicals Co. Ltd.) and PP (Eltex® P HL001PF from Ineos); - component (D), polyphenylene ether: Noryl™ PPO 640-111 from Sabic; - component (E), charge: CaCO3 coated with stearic acid, D90 < 10.50 μη, D50 < 2.50 μη, from Nicem srl, Casazza (Bergamo), Italy; - component (F), silicone oil: Genioplast® Fluid 110 from Wacker Chemie AG, Munich, Germany; - component (G): blend of ultra-high molecular weight (UHMW) silicone resin Luhvobatch 7001 from Lehmann & Voss & Co. KG, Hamburg, and oleamide from Ultrabatch srl of Castano Primo (Milan), Italy; - component (H), additive: antioxidant, mixture of Petition 870250049788, dated 06 / 13 / 2025, page 33 / 50 14 / 20 Nymanox MD 124 (hydrazine, CAS No. 32687-78-8) and Nymanox RS 14 (phenolic triazine, CAS No. 27676-62-6) from Nymco, Castano Primo (Milan), Italy. EXAMPLE 1

[0046] This example relates to the production of three compositions of the invention and, for comparison, of two compositions according to the prior art. Hereinafter, the three compositions according to the invention are indicated respectively as I1, I2 and I3, while the compositions of the prior art are indicated as C1 and C2; the latter are in accordance with EP 2196500 B1 and WO 2012 / 091230 A1, respectively.

[0047] The components indicated in Table 1 below were compounded in a twin-screw extruder in the reported percentage amounts by weight: Table 1 Component % by weight I1 I2 I3 C1 C2 (A) SEBS 22.2 22.2 20.2 31.5 25 (B) Naphthenic oil 40.7 40.7 40.7 / 21.5 Paraffin oil / / / 40.5 21.5 (C) EP 8.7 8.7 8.7 / / (C) PP / / / 9.9 9.9 (D) Polyphenylene ether 8.9 8.9 8.9 4.5 4.5 (E) CaCO3 coated with stearic acid 13.3 13.3 13.3 12.6 12.6 (F) Silicone oil 5.0 0.7 0.7 / / (G) UHMW silicone resin + oleamide 0.7 5.0 7.0 1.0 5 (H) Antioxidants 0.5 0.5 0.5 / /

[0048] In composition I3, component A is of the preferred type, i.e., with high molecular weight, giving rise to a 5% by weight solution in toluene with viscosity > 350 cP when measured at 25 °C according to ASTM D2196 standard. Petition 870250049788, dated 06 / 13 / 2025, page 34 / 50 15 / 20 Method A.

[0049] Composition C2 is not reported as such in WO 2012 / 091230 A1: it was produced using the minimum amount of component A permitted by this prior art document and using a 1:1 mixture of paraffinic oil and naphthenic oil as softener; these characteristics were chosen to obtain a composition as close as possible, while remaining within the limits of said document, to the compositions of the present invention, in order to highlight the different and advantageous results obtained by the latter.

[0050] For the production of the compositions of the invention, the components SEBS, EP, antioxidants, ultra-high molecular weight (UHMW) silicone + oleamide and EPI were dosed into the main hopper of the extruder; CaCO3 was added through a side doser in the center of the extruder; naphthenic oil was dosed with an injector at the beginning of the extruder; silicone was dosed with a second injector at the beginning of the extruder. The extruder temperatures are in the range of 195 to 200 °C, speed of 300 rpm, flow rate of 350 kg / h.

[0051] For the production of the state-of-the-art compositions, the components were added following exactly the same process described above, in order to obtain comparable results. EXAMPLE 2

[0052] This example deals with measuring the abrasion resistance of the compositions of the invention and the state of the art.

[0053] The tests were carried out with an apparatus assembled in the applicant's laboratories, schematically illustrated in Figure 1. In summary, the apparatus 10 comprises a roller 11 with a circular cross-section and Petition 870250049788, dated 06 / 13 / 2025, p. 35 / 50 16 / 20 with a diameter of 20 mm, on which a first sample 12 of a test composition is wound, completely covering the circular surface of the roll. The apparatus further comprises two clamps, 13 and 13', for fixing a second sample, 14, of the test composition, in the form of a ribbon; sample 14 is held taut against sample 12 by a constant force due to a 0.88 kg metal part 15 fixed to the lower clamp 13'; the angle formed by the two sections of sample 14 on opposite sides of the roll 11 is 120°. The test is performed by rotating the roll 11 and therefore the sample 12 at 105 rpm and counting the number of cycles before the sample 14 breaks using a counter 16. A first series of tests was carried out at 23 + / -3 °C; A second series of tests was carried out at 75 + / -3 °C, positioning device 10 in a climate chamber.

[0054] The compositions obtained in Example 1 (both of the invention and of the prior art) were used to produce tapes with a thickness of 2.0 mm; the samples in the tests had a width of 17 mm and a length of 150 ± 10 mm.

[0055] The number of cycles required to break down the samples at the two test temperatures is reported in Table 2 below: Table 2 Nominal Temperature (°C) Sample Composition I1 I2 I3 C1 C2 23 >500,000 >500,000 >700,000 <50,000 44,500 75 15,000 30,000 55,000 <5,000 4,000

[0056] Samples produced with the compositions of the invention withstand a number of abrasion cycles more than ten times greater than that of the prior art sample at 23 °C. Petition 870250049788, dated 06 / 13 / 2025, page 36 / 50 17 / 20 and at least three times (and even more than ten times) higher than that of the prior technique samples at 75 °C. Particularly noteworthy are the results obtained with the parts produced with composition I3, which, at both test temperatures, resist abrasion for a number of cycles well over ten times the number of cycles achieved before rupture by the prior technique samples. EXAMPLE 3

[0057] The composition I1 produced as described in Example 1 was used to prepare samples for stress-strain measurements aimed at determining the elongation at break of samples shaped according to the KSM 6518 standard.

[0058] Three different production runs, referred to below as R1, R2 and R3, were carried out with the composition of the invention, as described in Example 1. With each composition produced, three samples were produced by injection molding, indicated below as R#a, R#b and R#c.

[0059] Each sample was tested for elongation at break using tests in accordance with KSM 6518 standards; measurements were performed at 100 °C. The results obtained in the tests are presented in Tables 3 and 4 below, which show, respectively, the absolute values ​​obtained in the tests and a statistical analysis of the same. Table 3 Sample No. Tensile strength at 100% (MPa) Tensile strength at 200% (MPa) Tensile strength at 300% (MPa) Tensile strength at rupture (MPa) Elongation at rupture (%) R1a 0.257 0.369 0.476 0.928 926.3 R1b 0.253 0.377 0.480 0.969 977.9 Petition 870250049788, dated 06 / 13 / 2025, page 37 / 50 18 / 20 Sample No. Tensile strength at 100% (MPa) Tensile strength at 200% (MPa) Tensile strength at 300% (MPa) Tensile strength at rupture (MPa) Elongation at rupture (%) R1c 0.258 0.380 0.480 1.010 1022.7 R2a 0.300 0.438 0.548 1.040 928.9 R2b 0.307 0.448 0.562 1.120 964.3 R2c 0.296 0.435 0.545 1.100 983.0 R3a 0.287 0.423 0.539 1.180 959.3 R3b 0.308 0.456 0.589 1.260 981.3 R3c 0.287 0.417 0.535 1.050 853.8 Table 4 Series n = 9 Tensile strength at 100% (MPa) Tensile strength at 200% (MPa) Tensile strength at 300% (MPa) Tensile strength at rupture (MPa) Elongation at rupture (%) x 0.284 0.416 0.528 1.07 955.3 s 0.0220 0.0328 0.0403 0.15 48.0 ν 7.75 7.87 7.63 9.74 5.03

[0060] Fig. 2 graphically presents the stress-strain behavior trend of three tested samples, one for each of the preparations R1, R2, and R3; the curve for only one sample for each preparation is shown in the figure for greater clarity of representation, since the three curves for the samples of each preparation were very close. In particular, Fig. 2 presents the stress-strain curves obtained with sample R1c (lower, dotted curve), with sample R2c (central, solid curve), and with sample R3b (upper, dashed curve).

[0061] Similar results were obtained with the Petition 870250049788, dated 06 / 13 / 2025, pp. 38 / 50 19 / 20 compositions I2 and I3, which, produced in a large number of series, showed elongation at break values ​​between 800 and 1200% and ultimate loads between 0.5 and 1.4 MPa at 100 °C.

[0062] Similar tests performed at 25 °C on samples prepared with compositions I1, I2 and I3 resulted in elongation at break values ​​between 450 and 650%.

[0063] Particularly interesting is the behavior of the compositions of the invention compared with those of the prior art regarding the tendency of elongation at break at different temperatures: the compositions of both prior art documents considered show a decrease in the elongation at break value with increasing temperature: see, in this respect, Table 1 in EP 2196500 B1 and Table 2 in WO 2012 / 091230 A1, whose relevant data are reproduced below: Table 5 Example Document Elongation at break (%) 23 / 25 °C 100 °C EP 2196500 B1 1 750 430 2 1100 700 3 650 500 WO 2012 / 091230 A1 3 810 410 4 820 420 5 830 410 6 820 400 7 > 800 460

[0064] This behavior of the prior art compositions was confirmed by the present inventors who, in tests carried out on samples produced with compositions C1 and C2, measured elongation at break values ​​at 75 °C of 420 % for a sample produced with composition C1, and Petition 870250049788, dated 06 / 13 / 2025, pp. 39 / 50 20 / 20 of 460% for a sample produced with composition C2.

[0065] Conversely, the compositions of the invention exhibit elongation at break values ​​that increase with increasing temperature.

[0066] An increase in elongation at break with increasing temperature, as exhibited by articles produced with the compositions of the present invention (and contrary to the behavior of prior art compositions), is useful when a product made with these compositions must stretch, bend or, in any case, be stressed in elongation when working at high temperatures, as happens, for example, with bellows of a washing machine working at 90 °C or a washer-dryer working at temperatures up to 130 °C.

[0067] Subsequent tests performed with bellows-shaped molded parts showed very good bellows behavior thanks to the long elongation at break of the invention's compositions. Petition 870250049788, dated 06 / 13 / 2025, pages 40 / 50

Claims

1 / 5 CLAIMS 1. Thermoplastic elastomeric composition, characterized in that it comprises: (A) between 10 and 24% by weight of a hydrogenated triblock styrene copolymer having a melt flow index < 6 g / 10 min measured in accordance with ASTM D 1238 under a 5 kg load and at 200 °C, and a styrene % by weight between 10 and 35; (B) between 30 and 60% by weight of a naphthenic oil; (C) between 2 and 20% by weight of a polyolefin resin having a melt flow index < 10 g / 10 min, measured in accordance with ISO 1133 under a 2.16 kg load and at 230 °C; (D) between 4 and 20% by weight of a polyphenylene ether; (E) between 2 and 20% by weight of a filler; (F) between 0.1 and 8% by weight of a liquid silicone oil having a viscosity between 40 and 150 mm2 / s measured in accordance with ASTM D445; (G) between 0.1 and 8% by weight of one or more components selected from amides, silicone resins and polyurethanes.

2. Thermoplastic elastomeric composition, according to claim 1, characterized in that it further comprises up to 5% of one or more other additives selected from reinforcing agents, flame retardants, antimicrobial agents, UV blocking agents, hindered amine light stabilizers and antioxidants.

3. Thermoplastic elastomeric composition, according to claim 1 or 2, characterized in that the amount of hydrogenated styrene triblock copolymer is between 18 and 23% by weight.

4. Thermoplastic elastomeric composition, according to Petition 870260053875, dated 03 / 06 / 2026, page 11 / 20 2 / 5 with any of claims 1 to 3, characterized in that the amount of naphthenic oil is between 38 and 45% by weight.

5. Thermoplastic elastomeric composition, according to any one of claims 1 to 4, characterized in that the amount of polyolefin resin is between 5 and 15% by weight.

6. Thermoplastic elastomeric composition, according to any one of claims 1 to 5, characterized in that the amount of polyphenylene ether is between 7 and 15% by weight.

7. Thermoplastic elastomeric composition, according to any one of claims 1 to 6, characterized in that the amount of filler is between 8 and 14% by weight.

8. Thermoplastic elastomeric composition, according to any one of claims 1 to 7, characterized in that the amount of silicone oil is between 3 and 6% by weight.

9. Thermoplastic elastomeric composition, according to any one of claims 1 to 8, characterized in that the amount of component (G) is between 0.1 and 2% by weight.

10. Thermoplastic elastomeric composition, according to any one of claims 1 to 9, characterized in that the hydrogenated styrene triblock copolymer is selected from hydrogenated styrene-ethylene-propylene-styrene (SEPS), hydrogenated styrene-butadiene-styrene (SBS), hydrogenated styrene-isoprene-styrene (SIS), hydrogenated styrene-isoprene-butadiene-styrene (SIBS), hydrogenated ethylene / propylene block copolymer (SEP), hydrogenated styrene-ethylene / (ethylene / propylene)-styrene (SEEPS) and, preferably, hydrogenated styrene-ethylene-butadiene-styrene (SEBS) and mixtures thereof.

11. Thermoplastic elastomeric composition, according to any one of claims 1 to 10, characterized in that the naphthenic oil has a viscosity in the range of 50 to 100 mm² / s, as measured in accordance with ASTM D 445.

12. Thermoplastic elastomeric composition, according to any one of claims 1 to 11, characterized in that the polyolefin is selected from polypropylene (PP), ethylene-propylene copolymer (EP), polyethylene (PE), thermoplastic polyolefins (TPO) and mixtures thereof.

13. Thermoplastic elastomeric composition, according to any one of claims 1 to 12, characterized in that the polyphenylene ether is selected from poly(2,6-dimethyl-1,4-phenylene) ether, poly(2,6-diethyl-1,4-phenylene) ether, poly(2,6-dipropyl-1,4-phenylene) ether, poly(2-methyl-6-ethyl-1,4-phenylene) ether, poly(2-methyl-6-propyl-1,4-phenylene) ether, poly(2-ethyl-6-propyl-1,4-phenylene) ether, poly(2,6-diphenyl-1,4-phenylene) ether copolymers, poly(2,6-dimethyl-1,4-phenylene) ether and poly(2,3,6-trimethyl-1,4-phenylene) ether copolymers poly(2,6-dimethyl-1,4-phenylene) and poly(2,3,6-triethyl-1,4-phenylene) ether and mixtures thereof.

14. Thermoplastic elastomeric composition, according to any one of claims 1 to 13, characterized in that the polyphenylene ether has a weight-average molecular weight between 20,000 and 60,000 g / mol, an apparent density between 350 and 550 kg / dm3, as measured according to ISO 1183, and a degree of polymerization corresponding to an intrinsic viscosity of 0.2 to 0.8 dL / g, as measured in chloroform as solvent at 25 °C.

15. Thermoplastic elastomeric composition, according to any one of claims 1 to 14, characterized in that the filler is in the form of powders with a grain size between 0.01 and 5 µm.

16. Thermoplastic elastomeric composition, according to any one of claims 1 to 15, characterized in that the filler is an inorganic material selected from talc, clay, calcium carbonate, silica, kaolin, calcined kaolin, iron oxide, glass fibers, mica, titanium dioxide, carbon black, graphite, wollastonite or mixtures thereof.

17. Thermoplastic elastomeric composition, according to any one of claims 1 to 16, characterized in that component (G) is selected from oleamide, erucamide, a high molecular weight or ultra-high molecular weight silicone resin, a polyurethane, a polyester-based thermoplastic polyurethane, a polyether-based thermoplastic polyurethane and mixtures thereof.

18. Process for producing a thermoplastic elastomeric composition as defined in any one of claims 1 to 17, characterized in that it comprises feeding the solid components of the composition into an extruder, partly through a main hopper at the beginning of the extruder and partly through one or two side dosing stations (side feeders), and injecting the liquid components into the extruder at one or more feed ports between the beginning of the extruder and half its length, maintaining the extruder temperature profile between 160 and 240 °C.

19. Process, according to claim 18, characterized in that it further comprises a pellet cutting operation with a cutting and cooling system at the head, leaving the composition in the extruder head.

20. Elastomeric part, characterized in that it is produced by injection molding with the thermoplastic elastomeric composition as defined in any one of claims 1 to 17.

21. Elastomeric part, according to claim 20, characterized in that it is in the form of a bellows.

22. Elastomeric part, according to claim 20, characterized in that it is in the form of a gasket for the door of a washing machine or a washer-dryer. Petition 870260053875, dated 03 / 06 / 2026, page 15 / 20

Images