Thermoplastic elastomer composition comprising a block copolymer, a particular thermoplastic polymer, a filler and a plasticising agent

Abstract

The present invention relates to a thermoplastic elastomer composition comprising: a) at least one block copolymer; b) at least one thermoplastic polymer selected from polybutylene terephthalate, polymethylpentene and a mixture thereof; c) at least one filler; and d) at least one plasticising agent.

Description

[0001] DESCRIPTION

[0002] TITLE: Thermoplastic elastomeric composition comprising a block copolymer, a particular thermoplastic polymer, a filler and a plasticizing agent

[0003] The present invention relates to a thermoplastic elastomeric composition comprising at least one block copolymer, at least one particular thermoplastic polymer, at least one filler, and at least one plasticizing agent. The present invention also relates to a process for preparing the composition as defined above, and also to a cable comprising said composition.

[0004] Technical field

[0005] Cable sheathing and insulation can be used for many applications, including transportation, construction, electronics, and the energy market. The transportation sector includes applications in automotive, rail, and military transportation. The construction sector includes individual construction and public or industrial investments. The energy market includes, for example, offshore applications, underground drilling infrastructure, renewable energy production equipment (such as solar panels, offshore and onshore wind turbines), and batteries, such as electric vehicle batteries.

[0006] In the automotive industry, different classifications are used to designate cables. Classes Tl to T5 (or A to E) are most often cited and define the temperature range of the cable. Class Tl designates the temperature range from -40 to 85°C, class T2 from -40 to 105°C, class T3 from -40 to 125°C, class T4 from -40 to 150°C, and class T5 from -40 to 175°C, according to ISO 6722.

[0007] As for the T4 class, various compounds can be used.

[0008] For example, crosslinkable polyethylene or silicone-based compounds can be mentioned. However, this type of technology requires a second processing step after the cable is extruded: a "crosslinking" step. This step is necessary to enable the cable to meet the application requirements. Furthermore, different types of crosslinking exist, including crosslinking under water vapor / ultraviolet (UV) irradiation / electron beams / etc. These expensive processes also make the cables mechanically non-recyclable and therefore very difficult to recover. Other materials can also be used, such as thermoplastic polyurethanes, which are non-crosslinkable. However, they have very low resistance to humidity and hydrolysis.

[0009] Cables based on ethylene tetrafluoroethylene (ETFE) fluorinated polymers can also be mentioned. These are cables belonging to class T5 which could be used for class T4. However, they must be implemented over very high temperature ranges (> 300°C) and are therefore very energy-intensive.

[0010] It should also be noted that the materials mentioned above are inherently very hard / rigid, making the cable not very flexible.

[0011] Thus, the materials used in cables, and more generally the compositions comprising polymers, are not satisfactory with insufficient properties.

[0012] There is therefore a need for a non-crosslinkable composition which exhibits excellent mechanical properties, including after exposure to high temperatures, for example up to 175°C, very good fire resistance properties and a very good level of resistance to hydrolysis.

[0013] Thus, the aim of the present invention is to develop a composition having advantageous mechanical, fire resistance and hydrolysis resistance properties while avoiding additional manufacturing steps which are often costly and energy-consuming.

[0014] Statement of the invention

[0015] The present invention therefore relates to a thermoplastic elastomer composition comprising: a) at least one block copolymer; b) at least one thermoplastic polymer chosen from polybutylene terephthalate, polymethylpentene and their mixture; c) at least one filler; and d) at least one plasticizing agent.

[0016] Thanks to the composition according to the invention, excellent mechanical properties are obtained, in particular in terms of stress at 100% deformation, breaking strength and elongation at break, at room temperature. Good retention of said mechanical properties is also observed after exposure to high temperatures, in particular up to 175°C, in particular and for example up to 150°C in the long term, i.e. beyond 2000 hours, 175°C in the short term, i.e. beyond 100 hours, in particular beyond 200 hours, and less than 500 hours. Furthermore, excellent fire resistance and hydrolysis resistance properties are also obtained.

[0017] The invention also relates to a process for preparing the composition according to the invention.

[0018] Another subject of the invention is a cable comprising the composition according to the invention.

[0019] The expression "at least one" means one or more.

[0020] Unless otherwise indicated, the limits of a range of values ​​are included in that range, particularly in the expressions "between" and "ranging from ... to ...".

[0021] Block copolymer

[0022] The composition according to the invention comprises at least one block copolymer a).

[0023] The block copolymer according to the invention consists of one or more hard (or “rigid” or “thermoplastic”) segments connected to one or more soft (or “flexible” or “elastomeric”) segments.

[0024] Thus, the block copolymer(s) of the composition according to the invention comprise at least one soft block and at least one hard block.

[0025] By “soft” block (or also “flexible” or “elastomeric”), we mean a block which has a glass transition temperature (Tg) lower than room temperature (25°C), preferably lower than or equal to 10°C, and more preferably lower than 0°C.

[0026] By “hard” (or also “rigid” or “thermoplastic”) block is meant a block made up of polymerized monomers and having a glass transition temperature, or a melting temperature in the case of semi-crystalline polymers, greater than or equal to 80°C, preferably varying from 80°C to 250°C, more preferably varying from 80°C to 200°C, and in particular varying from 80°C to 180°C.

[0027] Typically, each of these segments or blocks (hard or soft) contains at least more than 5, generally more than 10 basic units (polymeric units).

[0028] In the present application, when reference is made to the glass transition temperature of a block copolymer, this is the glass transition temperature relative to the soft block (or elastomeric block) (unless otherwise indicated). Indeed, in a known manner, multi-block copolymers comprising at least one soft block and at least one hard block have two glass transition temperature peaks (Tg, measured according to ASTM D3418), the lower temperature being relative to the soft part of the block copolymer, and the higher temperature being relative to the hard part of the block copolymer.

[0029] Thus, the block copolymer(s) that can be used according to the invention preferably have a glass transition temperature (therefore a glass transition temperature of the soft block) which is less than or equal to 25°C, more preferably less than or equal to 10°C.

[0030] Also preferably, the glass transition temperature of the block copolymers which can be used according to the invention is greater than -130°C.

[0031] These block copolymers have, in their range, various molecular weights starting from low molecular weights to high molecular weights. Advantageously, said molecular weights range from 10 4 at 10 7 g / mol, preferably 2.5* 10 4 at 10 6 g / mol, more preferably 2.5* 10 4 at 2.5* 10 5 g / mol.

[0032] Advantageously, the block copolymer(s) are chosen from hard block / soft block / hard block triblock elastomers.

[0033] The soft block(s) of the block copolymer(s) that can be used according to the invention may be unsaturated soft blocks.

[0034] By unsaturated soft block, we mean that this block is derived at least in part from conjugated diene monomers.

[0035] The unsaturated soft blocks that can be used according to the invention are preferably chosen from any homopolymer of a monomer having conjugated dienes and any copolymer of a monomer having conjugated dienes with another monomer.

[0036] In particular, the unsaturated soft blocks which can be used according to the invention may be chosen from: a) any homopolymer obtained by polymerization of a conjugated diene monomer having from 4 to 12 carbon atoms; b) any copolymer obtained by copolymerization of one or more conjugated dienes with each other or with one or more aromatic vinyl compounds having from 8 to 20 carbon atoms; c) a ternary copolymer obtained by copolymerization of ethylene, of an α-olefin having from 3 to 6 carbon atoms with a non-conjugated diene monomer having from 6 to 12 carbon atoms, such as for example the elastomers obtained from ethylene, of propylene with a non-conjugated diene monomer of the aforementioned type such as in particular hexadiene-1,4, ethylidene norbornene, dicyclopentadiene; (d) a copolymer of isobutene and isoprene (butyl diene rubber), as well as halogenated, in particular chlorinated or brominated, versions of this type of copolymer.Suitable conjugated dienes include, in particular, isoprene, 1,3-butadiene, piperylene, 1-methylbutadiene, 2-methylbutadiene, 2,3-dimethyl-1,3-butadiene, 2,4-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 3-methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene, 2,3-dimethyl-1,3-pentadiene, 2,5-dimethyl-1,3-pentadiene, 2-methyl-1,4-pentadiene, 1,3-hexadiene, 2-methyl-.

[0037] 1,3-hexadiene, 2-methyl-1,5-hexadiene, 3-methyl-1,3-hexadiene, 4-methyl-1,3-hexadiene, 5-methyl-1,3-hexadiene, 2,5-dimethyl-1,3-hexadiene, 2,5-dimethyl-

[0038] 2,4-hexadiene, 2-neopentyl-1,3-butadiene, 1,3-cyclopentadiene, methylcyclopentadiene, 2-methyl-1,6-heptadiene, 1,3-cyclohexadiene, 1-vinyl-1,3-cyclohexadiene, and a mixture of these conjugated dienes; preferably, these conjugated dienes are selected from isoprene, butadiene and a mixture containing isoprene and / or butadiene.

[0039] Note that reactive functionalities such as maleic anhydride, glycidyl methacrylate or other functionalities intended for compatibilizing or chemical reactivity may be grafted onto this unsaturated soft block. However, preferably, this unsaturated soft block is not grafted with any reactive functionality.

[0040] Particularly preferably in the invention, the soft block(s) are chosen from the group consisting of polyisoprenes, polybutadienes, copolymers of butadiene and isoprene, copolymers of styrene and butadiene, copolymers of ethylene and butadiene, and mixtures of these polymers, these polymers being non-hydrogenated or partially hydrogenated.

[0041] The soft block(s) of the block copolymer(s) usable according to the invention may also be saturated soft blocks.

[0042] Generally speaking, these saturated soft blocks are obtained by hydrogenation of unsaturated soft blocks, or by simple copolymerization.

[0043] As explained previously, the block copolymer(s) that can be used according to the invention also comprise at least one hard block.

[0044] The hard block(s) can be made from polymerized monomers of various types.

[0045] In particular, the hard block(s) may be selected from the group consisting of polyolefins (polyethylene, polypropylene), polyurethanes, polyamides, polyesters, polyacetals, polyethers (polyethylene oxide, polyphenylene ether), polyphenylene sulfides, polyfluorinated compounds such as fluorinated ethylene-propylene (FEP), perfluoroalkoxy (PFA), and ethylene tetrafluoroethylene (ETFE), polystyrenes, polycarbonates, polysulfones, polymethylmethacrylate, polyetherimide, thermoplastic copolymers such as acrylonitrile-butadiene-styrene copolymer (ABS), and blends of these polymers.

[0046] Regarding polystyrenes, these are obtained from styrenic monomers.

[0047] By styrenic monomer is meant in the present description any monomer comprising styrene, unsubstituted or substituted. Among the substituted styrenes that may be mentioned, for example, methyl styrenes (for example o-methyl styrene, m-methyl styrene or p-methylstyrene, alpha-methylstyrene, alpha-2-dimethylstyrene, alpha-4-dimethylstyrene or diphenylethylene), para-tert-butyl styrene, chlorostyrenes (for example o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene or

[0048] 2.4.6-trichlorostyrene), bromostyrenes (e.g. o-bromostyrene, m-bromostyrene, p-bromostyrene, 2,4-dibromostyrene, 2,6-dibromostyrene or

[0049] 2.4.6-tribromostyrene), fluorostyrenes (e.g. o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, 2,4-difluorostyrene, 2,6-difluorostyrene or

[0050] 2.4.6-trifluorostyrene) or para-hydroxy-styrene.

[0051] Similar to what can be done for soft blocks, reactive monomers, or functionalities can always be included, in a minority manner, in the polymer chain of the hard block. However, preferably, the polymer chain of the block does not include such reactive monomers or functionalities.

[0052] Block copolymers that can be used according to the invention include multiblock copolymers of ethylene and alpha-olefins where the alpha-olefin is chosen from propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, norbornene, 1-decene, 1,5-hexadiene, ethylene or a combination of such compounds.

[0053] These multiblock copolymers of ethylene and alpha-olefins may comprise one or more hard segments comprising at least 98% by weight of ethylene, and one or more soft segments comprising less than 95% by weight, preferably less than 50% by weight of ethylene. Preferably the hard segments are present in an amount of 5 to 85% by weight.

[0054] For example, these ethylene and alpha-olefin multiblock copolymers can be supplied by the DOW company under the Engage and Infuse range.

[0055] Advantageously, the block copolymer(s) according to the invention are chosen from styrene / butadiene / styrene (SB S) polymers, styrene / ethylene-butylene / styrene (SEBS) polymers, styrene / ethylene / propylene / styrene (SEPS) polymers, styrene / ethylene / ethylene-propylene / styrene (SEEPS) polymers and mixtures thereof.

[0056] Particularly preferably, the block copolymer(s) according to the invention are chosen from styrene / ethylene-butylene / styrene (SEBS) polymers.

[0057] As a block copolymer that can be used according to the invention, mention may in particular be made of the styrene / ethylene-butylene / styrene (SEBS) polymer comprising 33% by weight of styrene units relative to the total weight of the polymer sold under the name “Calprene H6174S” by the company Dynasol.

[0058] Advantageously, the content of block copolymer(s) a) ranges from 5 to 40% by weight, preferably from 10 to 30% by weight, more preferably from 15 to 25% by weight relative to the total weight of the composition.

[0059] Thermoplastic polymer

[0060] As indicated previously, the composition according to the invention comprises at least one thermoplastic polymer b) chosen from polybutylene terephthalate, polymethylpentene and their mixture.

[0061] Preferably, the thermoplastic polymer is polybutylene terephthalate or polymethylpentene.

[0062] Advantageously, the content of thermoplastic polymer(s) b) ranges from 5 to 50% by weight, preferably from 10 to 40% by weight, more preferably from 10 to 30% by weight, better still from 15 to 25% by weight relative to the total weight of the composition.

[0063] Charge

[0064] As indicated previously, the composition according to the invention comprises at least one filler c).

[0065] Advantageously, filler c) is chosen from flame retardant fillers, preferably from halogenated flame retardant fillers, flame retardant synergists and mixtures thereof.

[0066] Preferably, the composition according to the invention comprises at least one flame retardant filler, more preferably a halogenated flame retardant filler.

[0067] As a halogenated flame retardant filler that can be used according to the invention, mention may be made of decabromodiphenyl ether (DBDPE), for example that sold under the trade name Saytex® 8010 by the company Albemarle. Preferably, the composition according to the invention comprises at least one flame retardant synergist.

[0068] As a flame retardant synergist that can be used according to the invention, antimony trioxide may be mentioned, for example that sold under the trade name Sicabatch 402001 by the company Sica de Chauny.

[0069] More preferably, the composition according to the invention comprises at least one flame retardant filler, more preferably a halogenated flame retardant filler, and at least one flame retardant synergist.

[0070] Advantageously, the content of filler(s) c) ranges from 10 to 40% by weight, preferably from 15 to 35% by weight, more preferably from 20 to 30% by weight relative to the total weight of the composition.

[0071] Advantageously, the content of flame-retardant filler(s) ranges from 5 to 30% by weight, preferably from 10 to 25% by weight, more preferably from 15 to 20% by weight relative to the total weight of the composition.

[0072] Advantageously, the content of flame retardant synergist(s) ranges from 1 to 15% by weight, preferably from 3 to 10% by weight, more preferably from 5 to 8% by weight relative to the total weight of the composition.

[0073] Plasticizing agent

[0074] The composition according to the invention further comprises d) at least one plasticizing agent.

[0075] Preferably, the plasticizing agent is chosen from oils.

[0076] Thus, preferably, the plasticizing agent is an oil (or plasticizing oil or extending oil).

[0077] At room temperature (25°C), these oils are liquids (that is to say, as a reminder, a substance having the capacity to eventually take the shape of their container) as opposed in particular to resins or rubbers which are by nature solid.

[0078] Preferably, said oil is chosen from polyolefinic oils (i.e., oils resulting from the polymerization of olefins, monoolefins or diolefins), mineral oils, such as paraffinic oils, naphthenic oils (low or high viscosity), aromatic oils, and mixtures of these oils.

[0079] Preferably, said oil is chosen from mineral oils, more preferably from paraffinic oils. Mention may in particular be made, as a plasticizing agent which can be used according to the invention, of mineral oil, or paraffinic mineral oil, sold under the name Pioner Ml 930 by the company H&R.

[0080] According to a particular embodiment, the content of plasticizing agent(s) d) ranges from 5 to 50% by weight, preferably from 10 to 40% by weight, more preferably from 15 to 35% by weight, even more preferably from 20 to 30% by weight relative to the total weight of the composition.

[0081] Preferably, the composition according to the invention is non-crosslinkable.

[0082] “Non-crosslinkable composition” means a composition which does not include a crosslinking agent, such as peroxides, silanes, etc.

[0083] With the absence of a crosslinking agent, the composition is ready for use. This is not the case for compositions comprising such a crosslinking agent, i.e. crosslinkable compositions, which require post-treatment, for example heating, radiation, etc., which is cumbersome both from an economic and an ecological point of view.

[0084] Polyolefin polymer

[0085] The composition according to the invention may further comprise e) at least one polyolefin polymer.

[0086] A polyolefin polymer is understood to mean a homopolymer or copolymer comprising one or more olefin units such as ethylene, propylene, butene-1, octene-1, butadiene, or any other alpha-olefin units.

[0087] Advantageously, the polyolefin polymer(s) are chosen from ethylene / propylene copolymers, polyethylene homopolymers, polypropylene homopolymers, and mixtures thereof, preferably from polypropylene homopolymers.

[0088] An example of a polyolefin polymer is polypropylene sold under the name PP 57 IP by the company Sabic.

[0089] According to a particular embodiment, the content of polyol polymer(s) e) ranges from 1 to 20% by weight, preferably from 2 to 10% by weight, more preferably from 4 to 8% by weight relative to the total weight of the composition.

[0090] Additional block copolymer

[0091] The composition according to the invention may further comprise f) at least one additional block copolymer. Advantageously, the additional block copolymer is different from the compounds as defined above, in particular different from the block copolymer a).

[0092] Advantageously, the additional block copolymer(s) f) are chosen from hard block / soft block diblock copolymers, different from the block copolymer(s) a).

[0093] The soft blocks and hard blocks that can be used may be those as defined above for block copolymers a).

[0094] Thus, the soft block(s) of the additional block copolymer(s) f) may be unsaturated soft blocks.

[0095] Note that reactive functionalities such as maleic anhydride, glycidyl methacrylate or other functionalities intended for compatibilisation or chemical reactivity can be grafted onto the unsaturated soft block.

[0096] Furthermore, similar to what can be done for soft blocks, reactive monomers, or functionalities, can always be included, in a minority manner, in the polymer chain of the hard block.

[0097] According to a preferred embodiment, the additional block copolymer(s) f) are chosen from functionalized block copolymers, preferably from functionalized hard block / soft block diblock copolymers.

[0098] Advantageously, at least one of the blocks, between the hard block and the soft block, is functionalized. Preferably, at least the soft block, preferably unsaturated, is functionalized. Particularly preferably, only the soft block, preferably unsaturated, is functionalized.

[0099] Advantageously, the additional block copolymer(s) f) are chosen from styrene / ethylene-butylene (SEB), styrene / ethylene-propylene (SEP), styrene / ethylene-ethylene-propylene (SEEP), styrene / isobutylene (SIB) polymers and their mixtures, preferably functionalized, for example functionalized by grafting maleic anhydride.

[0100] Particularly preferably, the additional block copolymer(s) f) are chosen from styrene / ethylene-butylene (SEB) polymers functionalized by grafting maleic anhydride.

[0101] Mention may in particular be made, as an additional block copolymer f) which may be used, of the styrene / ethylene-butylene (SEB) polymer grafted with maleic anhydride, such as that sold under the trade name FG1901 GT by the company Kraton. Advantageously, the content of additional block copolymer(s) f) ranges from 1 to 15% by weight, preferably from 2 to 10% by weight, more preferably from 2 to 7% by weight relative to the total weight of the composition.

[0102] The composition according to the invention may further comprise an additional particular additive.

[0103] Preferably, said additive is chosen from (poly)carbodiimides, such as for example bis(2,6-diisopropylphenyl)carbodiimide, in particular (poly)carbodiimides of the Hydrostab® family, such as for example Hydrostab® 2, Hydrostab® 3, etc. or Hystab®, such as for example Hystab® 2, Hystab® 10, etc.

[0104] Advantageously, said additional particular additive is present in a content ranging from 0.1 to 20% by weight, preferably from 0.2 to 10% by weight, more preferably from 0.3 to 5% by weight, even more preferably from 0.5 to 2% by weight relative to the weight of the composition.

[0105] Additives

[0106] The composition according to the invention may also comprise various additional additives and usually present in compositions comprising thermoplastic elastomers, different from the compounds mentioned above, such as for example protective agents such as antioxidants, antiozonants, and anti-UV agents and various processing agents or other stabilizers.

[0107] According to a particularly preferred embodiment of the invention, the composition according to the invention comprises: a) from 5 to 40% by weight of at least one thermoplastic elastomer chosen from styrene / butadiene / styrene (SBS) polymers, styrene / ethylene-butylene / styrene (SEBS) polymers, styrene / ethylene / propylene / styrene (SEPS) polymers, styrene / ethylene / ethylene-propylene / styrene (SEEPS) polymers and mixtures thereof relative to the total weight of the composition; b) from 5 to 50% by weight of at least one thermoplastic polymer chosen from polybutylene terephthalate, polymethylpentene and mixtures thereof relative to the total weight of the composition; c) from 10 to 40% by weight of at least one filler relative to the total weight of the composition; and d) from 10 to 50% by weight of at least one plasticizing agent relative to the total weight of the composition.The composition according to the invention may be available in any desired form, which may be obtained in particular by injection, extrusion, etc. methods. Advantageously, the composition according to the invention may be available in the form of cables.

[0108] The present invention also relates to a process for preparing the composition according to the invention comprising the following steps: i) mixing said block copolymer a) with said thermoplastic polymer b), said filler c) and said plasticizing agent d); ii) injecting into a mold or adding into an extruder die the mixture obtained at the end of step i).

[0109] The composition according to the invention can thus be prepared by mixing the constituents, then the mixture obtained can be introduced into a machine, for example a twin-screw extrusion machine. The mixture obtained can then be used for injection molding, for extrusion.

[0110] The present invention also relates to a cable comprising the composition according to the invention.

[0111] The present invention will now be described more specifically by way of examples, which are in no way limiting of the scope of the invention. However, the examples make it possible to support specific characteristics, variations, and preferred embodiments of the invention.

[0112] Examples

[0113] Method

[0114] A flame test was carried out on cables comprising compositions Al, A2 and A3, respectively. Thus, a flame test was carried out on five cables.

[0115] Each of these cables was ignited and the time taken for the flame to extinguish was measured (in seconds) as well as the length of unburned cable as specified in ISO 19642.

[0116] Preparation of the compositions

[0117] Compositions A1 to A4 as described below were prepared: the contents are expressed in % by weight in Table 1 below. [Table 1]

[0118] (1) sold by Dynasol under the trade name Calprene H6174S (comprising 33% by weight of styrene units);

[0119] (2) sold by the company Adeka Palmarole under the trade name Orgater TMNO;

[0120] (3) sold by the company MITSUI under the trade name TPX MX002;

[0121] (4) sold by MITSUI company under the trade name TPX DX845;

[0122] (5) sold by the company ALBEMARLE under the trade name SAYTEX 8010;

[0123] (6) sold by SABIC under the trade name PP571P;

[0124] (7) sold by H&R under the trade name Pioner M1930;

[0125] (8) styrene / ethylene-butylene copolymer functionalized with maleic anhydride sold by the company Kraton under the trade name FG1901 GT;

[0126] (9) fireproofing synergist sold by the company SICA DE CHAUNY under the trade name SIC AB ATCH 402001;

[0127] (10) sold by Schafer addditivsystem GmbH under the trade name Hydrostab® 10-PBT. The compositions as described above were first obtained by mixing the various ingredients in corrotating twin-screw extrusion. The product thus obtained was then extruded to obtain cables having an outer diameter of 1.4 mm. Therefore, the cable obtained from the composition Al is called Al cable, and so on. The cables Al, A2, A3 and A4 are cables according to the invention.

[0128] Results

[0129] Various characteristics were measured. The results are summarized in Table 2 below.

[0130] [Table 2]

[0131] It is clear that the cables according to the invention A1 to A4 have excellent mechanical properties, particularly in terms of deformation stress, breaking strength or even elongation at break. These excellent mechanical properties are obtained not only at room temperature but also after having undergone heat treatment at high temperatures and after a long duration. Indeed, very good retention of said mechanical properties is observed at high temperatures, up to 175°C. In particular, the cables do not crack after aging, that is to say after the various heat treatments as mentioned above.

[0132] It also appears that the cables according to the invention have very good fire resistance with very short extinguishing times. Indeed, it is considered that a cable has excellent fire resistance if the cable is extinguishable in less than 30 s, and if the length of cable burned is less than 450 mm. The cables according to the invention largely meet these two requirements. It also appears that the A3 and A4 cables according to the invention have excellent volume resistivity. Thus, they have excellent resistance to hydrolysis.

[0133] Therefore, the materials obtained comprising the compositions according to the invention, by meeting the required requirements, are excellent candidates for non-crosslinkable flexible materials of class T4.

Claims

CLAIMS 1. Thermoplastic elastomer composition comprising: a) at least one block copolymer; b) at least one thermoplastic polymer chosen from polybutylene terephthalate, polymethylpentene and their mixture; c) at least one filler; and d) at least one plasticizing agent.

2. Composition according to claim 1, characterized in that the block copolymer(s) are chosen from hard block / soft block / hard block triblock elastomers.

3. Composition according to claim 1 or 2, characterized in that the block copolymer(s) are chosen from styrene / butadiene / styrene polymers, styrene / ethylene-butylene / styrene polymers, styrene / ethylene / propylene / styrene polymers, styrene / ethylene / ethylene-propylene / styrene polymers and mixtures thereof, preferably from styrene / ethylene-butylene / styrene polymers.

4. Composition according to any one of the preceding claims, characterized in that the content of block copolymer(s) a) ranges from 5 to 40% by weight, preferably from 10 to 30% by weight, more preferably from 15 to 25% by weight relative to the total weight of the composition.

5. Composition according to any one of the preceding claims, characterized in that the thermoplastic polymer b) is polybutylene terephthalate or polymethylpentene.

6. Composition according to any one of the preceding claims, characterized in that the content of thermoplastic polymer(s) b) ranges from 5 to 50% by weight, preferably from 10 to 40% by weight, more preferably from 10 to 30% by weight, better still from 15 to 25% by weight relative to the total weight of the composition.

7. Composition according to any one of the preceding claims, characterized in that the filler is chosen from flame-retardant fillers, preference among halogenated flame retardant fillers, flame retardant synergists and their mixtures.

8. Composition according to any one of the preceding claims, characterized in that the content of filler(s) c) ranges from 10 to 40% by weight, preferably from 15 to 35% by weight, more preferably from 20 to 30% by weight relative to the total weight of the composition.

9. Composition according to any one of the preceding claims, characterized in that the plasticizing agent d) is chosen from oils, preferably mineral oils.

10. Composition according to any one of the preceding claims, characterized in that the content of plasticizing agent(s) d) ranges from 5 to 50% by weight, preferably from 10 to 40% by weight, more preferably from 15 to 35% by weight, even more preferably from 20 to 30% by weight relative to the total weight of the composition.

11. Composition according to any one of the preceding claims, characterized in that it further comprises e) at least one polyol polymer, preferably chosen from ethylene / propylene copolymers, polyethylene homopolymers, polypropylene homopolymers, and mixtures thereof, preferably from polypropylene homopolymers.

12. Composition according to any one of the preceding claims, characterized in that it further comprises f) at least one additional block copolymer, preferably chosen from functionalized block copolymers.

13. Composition according to the preceding claim, characterized in that the content of additional block copolymer(s) f) ranges from 1 to 15% by weight, preferably from 2 to 10% by weight, more preferably from 2 to 7% by weight relative to the total weight of the composition.

14. Process for preparing a composition as defined in any one of the preceding claims comprising the following steps: i) mixing said block copolymer a) with said thermoplastic polymer b), said filler c) and said plasticizing agent d); ii) injecting into a mold or adding into an extruder die the mixture obtained at the end of step i).

15. Cable comprising a composition as defined in any one of claims 1 to 13.

Images