Composition comprising clay and use thereof for preparing tubular structures to reduce oligomer extraction

Abstract

The invention relates to the use of a composition comprising at least one polyamide having an average number of carbon atoms per nitrogen atom of greater than 6, in particular greater than or equal to 7, in particular greater than or equal to 8, and a clay for producing tubular structures intended for transporting fuels, in particular gasoline, in particular alcohols, the invention relates to a tubular structure comprising at least one layer (1) comprising said composition and having a reduced extractable, in particular oligomers, from the fuel relative to the same structure comprising the same composition but not clay, the composition does not contain a polyamide obtained by polycondensation of m-xylylenediamine with a dicarboxylic acid Cb of C4 to C36.

Description

[0001] The present invention relates to a composition comprising clay and its use for reducing oligomer extraction. The present invention also relates to a tubular structure for transporting fuels, the tubular structure comprising such a composition. Existing technology

[0002] Automakers are seeking to reduce the extraction of compounds present in polyamide gasoline lines to ensure proper functioning of internal combustion engines and guarantee gasoline purity.

[0003] The extraction of oligomers and plasticizers used in gasoline lines reduces the efficiency of the heat engine (reducing the purity of the gasoline) and, in the case of oligomers, can even lead to clogging of the injectors. It is therefore important to reduce the extraction of these compounds (especially oligomers that are not dissolved in the essence) by the flavor.

[0004] Clay is a well-known technology, and there are many patents on the barrier effect of clay. However, only KR20210005390 (Shinil Chemical Ind co Ltd) discloses a specific composition based on PA11 or PA12, which contains clay as well as carbon nanotubes, MXD6 and modified ethylene octene rubber (EOR), and mentions the effect on extractables.

[0005] However, the use of NTC and MXD6 reduces the flexibility of the tube, which is disadvantageous for thermoforming and assembly of the tube.

[0006] Furthermore, long-chain polyamides (particularly PA12) are inherently poorly resistant to component extraction.

[0007] Therefore, there is a need to provide a composition which improves the resistance to extraction of components while maintaining good flexibility of the tube.

[0008] The present invention therefore relates to the use of a composition comprising at least one polyamide and a clay, said polyamide having an average number of carbon atoms per nitrogen atom greater than 6, in particular greater than or equal to 7, in particular greater than or equal to 8, for the preparation of a tubular structure intended for use in the transport of fuels, in particular gasoline, in particular alcohols, said tubular structure comprising at least one layer (1) comprising said composition and said tubular structure having a reduced content of extractables, in particular oligomers, extracted from said fuel relative to an identical structure comprising the same composition but without the clay.

[0009] The composition does not contain polyamides obtained by polycondensation of meta-xylylenediamine with dicarboxylic acids Cb among C4 to C36.

[0010] Thus, the inventors have discovered that a composition comprising a polyamide (whose average number of carbon atoms per nitrogen atom is greater than 6) and clay, but not comprising a semiaromatic polyamide (e.g. a polyamide obtained by polycondensation of m-xylylenediamine with a C4 to C36 dicarboxylic acid Cb), allows for a reduction in the extraction of these compounds by the fragrance (in particular oligomers not soluble in the fragrance), while maintaining good flexibility of the tubes prepared with said composition. Such tubes prepared with said composition further exhibit good properties for thermoforming and assembly thereof.

[0011] The extractables test developed by various manufacturers (particularly Volkswagen) consists in determining the proportion of extractables in a petrol transport pipe after the interior of the pipe has been in contact with hot alcohol-containing petrol and in weighing the evaporation residue of the petrol contained in the pipe, which corresponds to the extractables.

[0012] Then, only when the proportion of extractables is as low as possible (in particular, less than or equal to 8 g / m3 for soluble extractables) 2 , especially 6, and, for insoluble extractables, less than 1 g / m 2 , especially 0.8), the tested pipe can be used to transport gasoline (inner pipe surface).

[0013] Oligomers are polyamides which must have a lower number average molecular weight than the polyamide used in the composition, in particular the oligomers have a number average molecular weight of 1000 to 15000 g / mol, in particular 1000 to 10000 g / mol.

[0014] Thus, the proportion of extractables in the pipes prepared using the composition of the invention presents a reduction in extractables extracted from the fuel, in particular oligomers, compared to the proportion of extractables using the same structure comprising the same composition but without clay.

[0015] In one embodiment, the composition is free of carbon nanotubes.

[0016] In another embodiment, the composition is free of carbon nanotubes and polyamide obtained by polycondensation of m-xylylenediamine and dicarboxylic acids Cb among C4 to C36.

[0017] In this specification, all ratios given are by weight relative to the total composition.

[0018] About Clay

[0019] Clay is an inorganic filler that may be fine particles having a size of 0.1 to 10 nm. The clay may be flaky montmorillonite, hectorite, saponite, or vermiculite, and more preferably flaky montmorillonite, hectorite, saponite, or vermiculite that has been organically pretreated with an organic material.

[0020] The organic material may be an organic material containing tertiary ammonium or quaternary ammonium. The organic material may include one or more ammoniums selected from bis(2-hydroxyethyl)methyl tallow ammonium and dimethyl hydrogenated tallow ammonium. For example, montmorillonite organically treated with bis(2-hydroxyethyl)methyl tallow ammonium or montmorillonite organically treated with dimethyl hydrogenated tallow ammonium can be used as the clay.

[0021] The organic material may be selected from , maleate, succinate, acrylate, benzyl hydrogen, dimethyl distearyl ammonium and An organic material having any one of the functional groups of oxazoline.

[0022] The clay may be a mixed clay formed by mixing two or more types of clay selected from the group consisting of flaky montmorillonite, hectorite, saponite, and vermiculite, and more preferably a mixed clay formed by mixing two or more types of clay selected from the group consisting of flaky montmorillonite, hectorite, saponite, and vermiculite and subjecting the mixture to organic pretreatment. The organically pretreated mixed clay may be formed by mixing two or more types of clay in a reaction tank during clay preparation and then pretreating the resulting mixture with an organic material.

[0023] Advantageously, the clay is a nanoclay. Nanoclays are layered silicates having a monolayer thickness of 0.1 to 1 nm.

[0024] About polyamide

[0025] The nomenclature used to define polyamides is described in ISO Standard 1874-1:2011 “Plastiques — Matériaux polyamides (PA) pour moulage et extrusion — Partie 1: Designation” (especially on page 3 (Tables 1 and 2)) and is well known to those skilled in the art.

[0026] The polyamide of the present invention may be a homopolyamide or a copolyamide.

[0027] The polyamide has an average number of carbon atoms greater than 6, in particular greater than or equal to 7, in particular greater than or equal to 8, per nitrogen atom.

[0028] Advantageously, it is a homopolyamide.

[0029] It may be semi-crystalline or amorphous.

[0030] Preferably, it is an aliphatic polyamide, in particular a semicrystalline aliphatic polyamide.

[0031] In the sense of the present invention, semi-crystalline polyamides are polyamides having a glass transition temperature determined by dynamic mechanical analysis (DMA) in accordance with ISO Standard 6721-11:2019 and a melting temperature (Tm) determined in accordance with ISO Standard 11357-3:2013, and a crystallization enthalpy during the cooling step measured in DSC at a rate of 20 K / min of greater than 30 J / g, preferably greater than 35 J / g, in accordance with ISO Standard 11357-3, 2013.

[0032] In the sense of the present invention, amorphous polyamide means a polyamide having only a glass transition temperature (not a melting temperature (Tm)), or a polyamide with very little crystallinity, having a glass transition temperature and a melting point such that the crystallization enthalpy during the cooling step at a rate of 20 K / min, measured according to standard ISO 11357-3:2013, is less than 30 J / g, in particular less than 20 J / g, preferably less than 15 J / g.

[0033] In one embodiment, the semi-crystalline aliphatic polyamide is linear.

[0034] In one embodiment, the semicrystalline aliphatic polyamide is a homopolyamide, in particular a semicrystalline linear aliphatic homopolyamide.

[0035] The at least one semi-crystalline aliphatic polyamide is obtainable by polycondensation of at least one lactam, which may be chosen from C9 to C18 lactams, preferentially C10 to C18, more preferentially C10 to C12.

[0036] The C9 to C12 lactams are especially caprolactam, undecanolactam and laurolactam.

[0037] The at least one semicrystalline aliphatic polyamide may be obtained by polycondensation of at least one lactam and may therefore comprise a single lactam or several lactams.

[0038] Advantageously, said at least one semicrystalline aliphatic polyamide is obtained by polycondensation of a single lactam, and said lactam is chosen from laurolactam and undecanolactam, advantageously laurolactam.

[0039] The at least one semi-crystalline aliphatic polyamide is obtainable by polycondensation of at least one amino acid, which may be chosen from C9 to C18 amino acids, preferentially C10 to C18, more preferentially C10 to C12.

[0040] The amino acids C9 to C12 are 9-aminononanoic acid, 10-aminodecanoic acid, 10- aminoundecanoic acid, 12-aminododecanoic acid and 11-aminoundecanoic acid and derivatives thereof, in particular N-heptyl-11-aminoundecanoic acid.

[0041] When the at least one semi-crystalline aliphatic polyamide is obtained by polycondensation of at least one amino acid, it can thus comprise a single amino acid or several amino acids.

[0042] Advantageously, the semi-crystalline aliphatic polyamide is obtained by polycondensation of a single amino acid and the amino acid is chosen from 11-aminoundecanoic acid and 12-aminododecanoic acid, advantageously 11-aminoundecanoic acid.

[0043] The at least one semi-crystalline aliphatic polyamide can be obtained by polycondensation of at least one diamine Ca from C4 to C36, preferentially C6 to C18, preferentially C6 to C12, more preferentially C10 to C12, with at least one diacid Cb from C4 to C36, preferentially C6 to C18, preferentially C6 to C12, more preferentially C10 to C12.

[0044] The diamines can be linear or branched. Advantageously, they are linear.

[0045] The at least one C4 to C36 diamine Ca can in particular be chosen from 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8- octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12- dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, 1,16- hexadecanediamine and 1,18-octadecanediamine, octadecene diamine, eicosane diamine, docosane diamine and diamines obtained from fatty acids.

[0046] Advantageously, the at least one diamine Ca is from C6 to C18 and is chosen from 1,6- hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10- decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, 1,16-hexadecanediamine and 1,18- octadecanediamine.

[0047] Advantageously, the at least one C6 to C12 diamine Ca is in particular chosen from 1,6- hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10- decanediamine, 1,11-undecanediamine and 1,12-dodecanediamine.

[0048] Advantageously, the diamine Ca used is a C10-C12 diamine, in particular chosen from 1,10-decamethylenediamine, 1,11-undemethylenediamine, and 1,12-dodecamethylenediamine.

[0049] The at least one C4-C36 dicarboxylic acid Cb may be chosen from succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid, and diacids obtained from fatty acids.

[0050] The diacid may be linear or branched. Advantageously, it is linear.

[0051] Advantageously, the at least one Cb dicarboxylic acid is C6 to C18 and is chosen from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid.

[0052] Advantageously, the at least one Cb dicarboxylic acid is C6 to C12 and may be chosen from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid and dodecanedioic acid.

[0053] Advantageously, said at least one Cb dicarboxylic acid is C10 to C12 and is chosen from sebacic acid, undecanedioic acid and dodecanedioic acid.

[0054] When the semicrystalline aliphatic polyamide is obtained from the polycondensation of at least one diamine Ca and at least one dicarboxylic acid Cb, it may therefore comprise a single diamine or a plurality of diamines and a single dicarboxylic acid or several dicarboxylic acids.

[0055] Advantageously, the semicrystalline aliphatic polyamide is obtained from the polycondensation of a single diamine Ca with a single dicarboxylic acid Cb.

[0056] Advantageously, the aliphatic polyamide is chosen from PA10, PA11, PA12, PA1010, PA1012, in particular PA11 and PA12.

[0057] In one embodiment, the composition used comprises 1-10% by weight of clay;

[0058] In another embodiment, the composition used comprises, by weight:

[0059] 40-99%, in particular 40-98.9%, of at least one polyamide having an average number of carbon atoms per nitrogen atom greater than 6, in particular greater than or equal to 7, in particular greater than or equal to 8, obtained by the polycondensation of:

[0060] at least one amino acid in C9 to C18, preferably in C10 to C18, more preferably in C10 to C12, or

[0061] at least one lactam in C9 to C18, preferably in C10 to C18, more preferably in C10 to C12, or

[0062] at least one diamine Ca in C4 to C36, preferably in C6 to C18, preferably in C6 to C12, more preferably in C10 to C12, with at least one dicarboxylic acid Cb in C4 to C36, preferably in C6 to C18, preferably in C6 to C12, more preferably in C10 to C12;

[0063] polycondensation of m-xylylenediamine with C4-C36 dicarboxylic acids Cb is excluded;

[0064] 1-10% of clay;

[0065] 0-30%, in particular 1-30%, of at least one functionalized polyolefin;

[0066] 0-15%, in particular 0.1-15%, of at least one plasticizer;

[0067] 0-5% of carbon nanotubes;

[0068] 0-2% of additives;

[0069] the sum of all ingredients is 100% by weight.

[0070] In yet another embodiment, the composition used has the following composition by weight:

[0071] 40-99%, in particular 40-98.9%, of at least one polyamide, the average number of carbon atoms per nitrogen atom of which is greater than 6, in particular greater than or equal to 7, in particular greater than or equal to 8, the polyamide being obtained by polycondensation of:

[0072] at least one amino acid in C9 to C18, preferably in C10 to C18, more preferably in C10 to C12, or

[0073] at least one lactam in C9 to C18, preferably in C10 to C18, more preferably in C10 to C12, or

[0074] at least one diamine Ca in C4 to C36, preferably in C6 to C18, preferably in C6 to C12, more preferably in C10 to C12, with at least one dicarboxylic acid Cb in C4 to C36, preferably in C6 to C18, preferably in C6 to C12, more preferably in C10 to C12;

[0075] polycondensation of m-xylylenediamine with C4-C36 dicarboxylic acids Cb is excluded;

[0076] 1-10% of clay;

[0077] 0-30%, in particular 1-30%, of at least one functionalized polyolefin;

[0078] 0-15%, in particular 0.1-15%, of at least one plasticizer;

[0079] 0-5% of carbon nanotubes;

[0080] 0-2% of additives;

[0081] The sum of all ingredients is 100% by weight.

[0082] In one embodiment, the reduction of insoluble extractables in the composition used is at least 50%, in particular at least 60%.

[0083] In another embodiment, the reduction of soluble extractables in the composition used is at least 10%, in particular at least 15%.

[0084] In yet another embodiment, the reduction of insoluble extractables is at least 50%, in particular at least 60%, and the reduction of soluble extractables is at least 10%, in particular at least 15%.

[0085] Advantageously, the composition used has an impact resistance greater than 6 KJ / m2 2 measured according to ISO 179-1 :2010 / 1 eA (Charpy impact) on 80 mm x 10 mm x 4 mm size bars with V-notch, at a temperature of -40°C + / - 2°C, at a relative humidity of 50% + / - 10% for dry samples.

[0086] Concerning the functionalized polyolefin

[0087] The functionalized polyolefin (also called (B1)) can be a polymer of an alpha-olefin with reactive units (functional groups); such reactive units are acid, anhydride or epoxy functional groups. As examples, one can mention non-functionalized polyolefins (called (B2)) grafted or copolymerized or terpolymerized with unsaturated epoxide such as glycidyl (meth)acrylate, or with carboxylic acid or corresponding salt or ester such as (meth)acrylic acid which can be fully or partially neutralized with a metal such as Zn or the like, or with carboxylic anhydride such as maleic anhydride.

[0088] The non-functionalized polyolefin (B2) is typically a homopolymer or copolymer of an alpha-olefin or a diene (e.g. ethylene, propylene, 1-butene, 1-octene, butadiene). As examples, one can mention:

[0089] - Homopolymers and copolymers of polyethylene, in particular LDPE, HDPE, LLDPE (linear low-density polyethylene), VLDPE (very low-density polyethylene) and metallocene polyethylene.

[0090] - Homopolymers or copolymers of propylene.

[0091] - Ethylene / α-olefin copolymers, such as ethylene / propylene, EPR (abbreviation for ethylene-propylene-rubber) and ethylene / propylene / diene (EPDM).

[0092] - Styrene / ethylene-butylene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS) block copolymers.

[0093] - Copolymers of ethylene with at least one product chosen from the group consisting of salts or esters of unsaturated carboxylic acids, such as alkyl (meth)acrylates (for example methyl acrylate), or vinyl esters of saturated carboxylic acids, such as vinyl acetate (EVA), in which the proportion of comonomer can reach 40% by weight.

[0094] Functionalized polyolefins (B1) are, for example, PE / EPR mixtures, the weight ratio of which can vary widely (for example between 40 / 60 and 90 / 10), co-grafted with anhydrides, in particular maleic anhydride, according to a grafting rate of, for example, 0.01 to 5% by weight.

[0095] The functionalized polyolefin (B1) can be selected from the group consisting of (co)polymers (grafted with maleic anhydride or glycidyl methacrylate) of the following substances, wherein the grafting rate is, for example, 0.01 to 5% by weight:

[0096] - (co)polymers of PE, (co)polymers of PP, copolymers of ethylene with propylene, butene, hexene or octene, containing, for example, 35 to 80% by weight of ethylene;

[0097] - Ethylene / α-olefin copolymers, such as ethylene / propylene, EPR (abbreviation for ethylene-propylene-rubber) and ethylene / propylene / diene (EPDM).

[0098] - Styrene / ethylene-butylene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS) block copolymers.

[0099] - copolymers of ethylene and vinyl acetate (EVA) containing up to 40% by weight of vinyl acetate;

[0100] - copolymers of ethylene and (meth)acrylic acid alkyl ester, containing up to 40% by weight of (meth)acrylic acid alkyl ester;

[0101] - copolymers of ethylene and vinyl acetate (EVA) and (meth)acrylic acid alkyl ester, containing up to 40% by weight of comonomer.

[0102] The functionalized polyolefin (B1 ) can also be selected from ethylene / propylene copolymers wherein the majority of the propylene grafted with maleic anhydride is condensed with a monoamine polyamide (or polyamide oligomer) (products described in EP-A-0 342 066).

[0103] The functionalized polyolefin (B1 ) can also be a copolymer or terpolymer of at least the following units: (1 ) ethylene; (2) (meth)acrylic acid alkyl ester or vinyl ester of a saturated carboxylic acid; and (3) an acid anhydride such as maleic anhydride or a (meth)acrylic acid or an epoxy such as glycidyl (meth)acrylate.

[0104] As examples of the latter type of functionalized polyolefin, the following copolymers can be mentioned, wherein ethylene preferably represents at least 60% by weight of the copolymer and wherein the termonomer (functional group) represents for example 0.1 -10% by weight of the copolymer:

[0105] - ethylene / (meth)acrylic acid alkyl ester / (meth)acrylic acid or maleic anhydride or glycidyl (meth)acrylate copolymer;

[0106] - ethylene / vinyl acetate / maleic anhydride or glycidyl (meth)acrylate copolymer;

[0107] - ethylene / vinyl acetate or (meth)acrylic acid alkyl ester / (meth)acrylic acid or maleic anhydride or glycidyl (meth)acrylate copolymer.

[0108] In the aforementioned copolymers, the (meth)acrylic acid can be salified with Zn or Li.

[0109] The term "(meth)acrylic acid alkyl ester" in (B1 ) or (B2) means both methacrylic acid C1-C8 alkyl esters and acrylic acid C1-C8 alkyl esters and can be selected from methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, methyl methacrylate and ethyl methacrylate.

[0110] Furthermore, the previously cited polyolefins (B1 ) can also be crosslinked by any suitable method or agent (di-epoxide, di-acid, peroxide, etc.); the term functionalized polyolefin also encompasses mixtures of the previously cited polyolefins with a bifunctional reactant (such as a di-acid, a di-anhydride, a di-epoxide, etc.) which can react with these or with a mixture of at least two functionalized polyolefins which can react together.

[0111] The copolymers (B1) and (B2) described above can be copolymerized in a statistical or sequential manner and have a linear or branched structure.

[0112] The molecular weight, MFI and density of these polyolefins can also vary widely, as known by the person skilled in the art. MFI (abbreviation for melt flow index) is a measure of the flowability when molten. It is measured according to standard ASTM 1238.

[0113] Advantageously, the non-functionalized polyolefin (B2) is chosen from homopolymers or copolymers of polypropylene and any ethylene homopolymer or ethylene copolymer with a higher alpha-olefin comonomer (such as butene, hexene, octene or 4-methyl-1-pentene). One can mention for example PP, high density PE, medium density PE, linear low density PE, low density PE, very low density PE. The person skilled in the art knows that these polyethylenes are products from "free radical" processes, from "Ziegler" catalysis processes, or more recently from "metallocene" catalysis.

[0114] Advantageously, the functionalized polyolefin (B1) is chosen from any polymer comprising alpha-olefin units and units bearing a polar reactive functional group such as epoxy, carboxylic acid or carboxylic anhydride functional groups. As examples of such polymers, one can mention terpolymers of ethylene, alkyl acrylate and maleic anhydride or glycidyl methacrylate (such as Lotader® from the Applicant) or polyolefins grafted with maleic anhydride (such as Orevac® from the Applicant) as well as terpolymers of ethylene, alkyl acrylate and (meth)acrylic acid. One can also mention homopolymers or copolymers of polypropylene grafted with carboxylic anhydride then condensed with a polyamide or monoamine polyamide oligomer.

[0115] Concerning the plasticizer

[0116] The plasticizer can be present or not. If it is present, its weight ratio in the composition is at most 15%.

[0117] As examples, the plasticizer is chosen from: benzene sulfonamide derivatives, such as n-butyl benzene sulfonamide (BBSA); ethyl toluene sulfonamide or N-cyclohexyl toluene sulfonamide; hydroxy benzoic acid esters, such as p-hydroxy benzoic acid 2-ethylhexyl ester and p-hydroxy benzoic acid 2-decylhexyl ester; esters or ethers of tetrahydrofurfuryl alcohol, such as oligoethyleneoxy tetrahydrofurfuryl alcohol; and esters of citric acid or esters of hydroxy malonic acid, such as oligoethyleneoxy malonic acid ester.

[0118] The use of a mixture of plasticizers will not be outside the scope of the application.

[0119] Concerning the additives

[0120] The additive may be present in the composition at 0 to 2% by weight.

[0121] Clay is not included in the scope of additives.

[0122] The additives optionally used in the composition of the invention are conventional additives for polyamides and are well known to those skilled in the art and are notably described in EP2098580.

[0123] For example, they contain antistatic fillers (selected from carbon black, graphite, carbon fibers, carbon nanotubes (in particular carbon black and carbon nanotubes)), antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, fire-proofing agents, nucleating agents and dyes, reinforcing fibers, waxes and mixtures thereof.

[0124] Advantageously, the additives are chosen from antistatic fillers (chosen from carbon black, graphite, carbon fibers (especially carbon black)), antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, fire retardants, nucleating agents and dyes, reinforcing fibers, waxes and mixtures thereof.

[0125] More advantageously, the additive is selected from antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, fire retardants, nucleating agents and dyes, reinforcing fibers, waxes and mixtures thereof.

[0126] As an example, the stabilizer may be a UV stabilizer, an organic stabilizer or more generally a combination of organic stabilizers, such as phenolic antioxidants (e.g. Irganox® 245, 1098 or 1010 from Ciba-BASF), phosphite antioxidants (e.g. Irgafos® 126 and Irgafos® 168 from Ciba-BASF) and optionally further stabilizers (e.g. HALS, which means hindered amine light stabilizers) (e.g. Tinuvin® 770 from Ciba-BASF), anti-UV agents (e.g. Tinuvin® 312 from Ciba), or phosphorus-based stabilizers). Amine antioxidants (e.g. Naugard® 445 from Crompton) or multifunctional stabilizers (e.g. Nylostab® S-EED from Clariant) may also be used.

[0127] The stabilizer may also be a mineral stabilizer, for example a copper-based stabilizer. Examples of such mineral stabilizers include halides and copper acetate. Other metals, such as silver, may also be considered, but these are known to be less effective. These copper-containing compounds are typically associated with alkali metal halides, particularly potassium.

[0128] About tubular structures

[0129] In another aspect, the present invention relates to a tubular structure for transporting fuels, in particular gasoline, in particular alcohols, said tubular structure comprising at least one layer (1) comprising a composition as defined above.

[0130] All the features cited above for the use of the composition also apply to the tubular structure comprising at least one layer (1) comprising the composition as defined above.

[0131] In a first variant, the tubular structure is a single-layer structure.

[0132] In one embodiment, the tubular structure further comprises at least one barrier layer (2) selected from EVOH or PPA, said layer (1) being in contact with the fuel.

[0133] The expression "barrier layer" refers to a layer which is highly impermeable to the fluid being transported.

[0134] The term "PPA" refers to semiaromatic polyamide or polyphtalamide (PPA).

[0135] Said semiaromatic polyamide of the barrier layer is notably a semiaromatic polyamide of formula X / YAr (as described in EP1505099), notably a semiaromatic polyamide of formula D / XT, wherein D is chosen from units obtained from amino acids, units obtained from lactams, and units corresponding to the formula (Ca diamine).(Cb diacid), wherein a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, a and b are each between 4 and 36, advantageously between 9 and 18;

[0136] XT represents a unit obtained by polycondensation of Cx diamine and terephthalic acid, wherein x represents the number of carbon atoms of Cx diamine, x being between 6 and 36, advantageously between 9 and 18,

[0137] Of note are polyamides of the formula D / 6T, D / 9T, D / 10T or D / 11T, D being as defined above, in particular polyamides PA6 / 6T, 66 / 6T, 61 / 6T, PA11 / 10T, 11 / 6T / 10T, MXDT / 10T or MPMDT / 10T, BACT / 10T aromatic amides, and block copolymers, in particular polyamide / polyether (PEBA) or

[0138] Or copolyamide X2T / X'2Ar, X2 and X'2 each independently represent a linear or branched C6-C13 aliphatic diamine, notably, the semiaromatic polyamide is selected from PA9T, PA9T / 9'T, PA10T / 6T, PA6T / 6I, PA6T / 66.

[0139] 9' corresponds to the nonanediamine positional isomer methyloctanediamine.

[0140] In a second variant, the tubular structure is a double-layer structure comprising or consisting of, from the outside to the inside:

[0141] EVOH / / (1) or PPA / / (1).

[0142] In one embodiment, the tubular structure further comprising at least one barrier layer (2) chosen from EVOH or PPA comprises at least one outermost layer (3) located above the barrier layer (2), said outer layer (3) mainly comprising at least one aliphatic polyamide or consisting of more than 75% aliphatic units, in particular said aliphatic polyamide having an average number of carbon atoms per nitrogen atom comprised between 9.5 and 18, advantageously between 11 and 18.

[0143] The aliphatic polyamide is as defined above.

[0144] In a third variation, the tubular structure is a three-layer structure, which is composed from the outside to the inside:

[0145] (3) / / EVOH / / (1) or (3) / / PPA / / (1).

[0146] In one embodiment, the tubular structure further comprises at least one barrier layer (2) selected from EVOH or PPA or at least one outermost layer (3) located above the barrier layer (2), the tubular structure further comprises at least one layer (4), the layer (4) mainly comprising at least one aliphatic polyamide or consisting of more than 75% aliphatic units, the aliphatic polyamide being selected from:

[0147] - polyamides, denoted A, having an average number of carbon atoms per nitrogen atom, denoted CA, comprised between 4 and 8.5, preferably between 4 and 7;

[0148] - polyamides denoted B and wherein the average number of carbon atoms per nitrogen atom denoted CB is comprised between 7 and 10, preferably between 7.5 and 9.5;

[0149] - polyamides, denoted C, having an average number of carbon atoms per nitrogen atom, denoted CC, comprised between 9 and 18, preferably between 10 and 18;

[0150] Provided that, in the case where said layer (4) comprises at least three polyamides, at least one of those polyamides A, B or C is excluded,

[0151] The layer (4) is located between the barrier layer (2) and the layer (1) and / or between the outer layer (3) and the barrier layer (2); or

[0152] The layer (4) is an adhesive layer, the thickness of which is at most 15% of the structure (MLT).

[0153] In a fourth modification, the tubular structure is a three-layer structure, which is composed from the outside to the inside:

[0154] EVOH / / (4) / / (1) or PPA / / (4) / / (1).

[0155] In the fifth modification, the tubular structure is a four-layer structure, which is composed from the outside to the inside as follows:

[0156] (3) / / (4) / / EVOH / / (1) or (3) / / (4) / / PPA / / (1).

[0157] In the sixth modification, the tubular structure is a five-layer structure, and its composition from the outside to the inside is as follows:

[0158] (3) / / (4) / / EVOH / / (4) / / (1) or (3) / / (4) / / PPA / / (4) / / (1).

[0159] In another embodiment, there is a layer (4') which essentially comprises or consists of more than 75% of aliphatic units of at least one aliphatic polyamide selected from:

[0160] - polyamides, denoted A, having an average number of carbon atoms per nitrogen atom, denoted CA, comprised between 4 and 8.5, preferably between 4 and 7;

[0161] - polyamides denoted B and wherein the average number of carbon atoms per nitrogen atom denoted CB is comprised between 7 and 10, preferably between 7.5 and 9.5;

[0162] - polyamides, denoted C, having an average number of carbon atoms per nitrogen atom, denoted CC, comprised between 9 and 18, preferably between 10 and 18;

[0163] Provided that, in the case where said layer (4') comprises at least three polyamides, at least one of those polyamides A, B or C is excluded, or

[0164] said layer (4') being an adhesive layer, the thickness of which is at most 15% of said structure (MLT),

[0165] The at least polyamide of the layer (4') may be the same as or different from the polyamide of the layer (4);

[0166] The layer (4') is located between the outer layer (3) and the barrier layer (2), and the adhesive layer (4) is located between the barrier layer (2) and the layer (1).

[0167] The aliphatic polyamide is as defined above.

[0168] In the seventh variation, the tubular structure is a five-layer structure, and its composition from the outside to the inside is as follows:

[0169] (3) / / (4') / / EVOH / / (4) / / (1) or (3) / / (4') / / PPA / / (4) / / (1),

[0170] Layer (4) is an adhesive layer.

[0171] About the composition itself

[0172] In another aspect, the present invention relates to a composition comprising, by weight:

[0173] 40-98%, in particular 40-97.9%, of at least one polyamide having an average number of carbon atoms per nitrogen atom greater than 6, in particular greater than or equal to 7, in particular greater than or equal to 8, obtained by the polycondensation of:

[0174] at least one amino acid selected from C9 to C18, preferably C10 to C18, more preferably C10 to C12, or

[0175] at least one lactam from C9 to C18, preferably C10 to C18, more preferably C10 to C12, or

[0176] at least one diamine Ca from C4 to C36, preferably C6 to C18, preferably C6 to C12, more preferably C10 to C12, and at least one dicarboxylic acid Cb from C4 to C36, preferably C6 to C18, preferably C6 to C12, more preferably C10 to C12,

[0177] Excluding the polycondensation of m-xylylenediamine with C4 to C36 dicarboxylic acids Cb;

[0178] 1-10% clay;

[0179] 1-30% of at least one functionalized polyolefin;

[0180] 0-15%, in particular 0.1-15%, of at least one plasticizer;

[0181] 0-5% carbon nanotubes;

[0182] 0-2% of at least one additive;

[0183] The sum of all ingredients is 100% by weight.

[0184] All features cited above for the use of the composition also apply to the composition itself.

[0185] In another embodiment, the composition defined in the preceding embodiments does not contain carbon nanotubes.

[0186] In another embodiment, the present invention is directed to a composition comprising, by weight:

[0187] 40-98%, in particular 40-97.9%, of at least one polyamide having an average number of carbon atoms per nitrogen atom greater than 6, in particular greater than or equal to 7, in particular greater than or equal to 8, obtained by the polycondensation of:

[0188] at least one amino acid selected from C9 to C18, preferably C10 to C18, more preferably C10 to C12, or

[0189] at least one lactam from C9 to C18, preferably C10 to C18, more preferably C10 to C12, or

[0190] at least one diamine Ca from C4 to C36, preferably C6 to C18, preferably C6 to C12, more preferably C10 to C12, and at least one dicarboxylic acid Cb from C4 to C36, preferably C6 to C18, preferably C6 to C12, more preferably C10 to C12,

[0191] Excluding the polycondensation of m-xylylenediamine with C4 to C36 dicarboxylic acids Cb;

[0192] 1-10% clay;

[0193] 1-30% of at least one functionalized polyolefin;

[0194] 0-15%, in particular 0.1-15%, of at least one plasticizer;

[0195] 0-5% carbon nanotubes;

[0196] 0-2% of at least one additive;

[0197] The sum of all ingredients is 100% by weight. Example

[0198] Hereinafter, the present invention will be described in more detail through specific examples. The following examples are merely illustrations to help understand the present invention, and the scope of the present invention is not limited thereto.

[0199] Preparation of organically pretreated clay components

[0200] First, montmorillonite, hectorite, and saponite (which were dispersed in water and impurities removed) were added at a weight ratio of 1:1:1 and mixed at 60°C while stirring to prepare a clay component dispersion solution. Next, dimethyl hydrogenated tallow ammonium (tertiary ammonium, adjusted to a pH of 4 to 5 and then dissolved in the clay component dispersion solution at 60°C) was added to a reaction tank at 90 milliequivalents per 100g of the clay component dispersion solution and subjected to an exchange reaction at 60°C for approximately 20 to 60 minutes while stirring to prepare a clay component. The clay component reacted using a filtration device was then dried in a fluid dryer and then ground using a grinding device to obtain a powder having a size of 10 to 40 microns.

[0201] Production of polyamide composite resins

[0202] The component ratios listed in Table 1 below for Examples 1 and 2 and Comparative Examples 1 to 4 were mixed, and then a twin-screw extruder was used to produce a polyamide composite resin. Resin, rubber, heat stabilizer, lubricant and viscosity thickener were injected through the main feeder, and an organic pretreated clay component was injected and produced through the side feeder. In the case where the clay component is injected into the main feeder, coagulation of the clay component may occur, and therefore it is preferred to use a side feeder or a spray method to inject the clay component. A device in which disordered kneading is possible to improve dispersibility can be used as the screw of the extruder. In addition, the extrusion temperature in the kneading zone is preferably maintained at a temperature of 250°C or lower. When the extrusion temperature is greater than 250°C, the domain size becomes excessively fine and the barrier properties may be reduced. The kneaded polyamide composite material is granulated by a cutter and then dried using a dehumidifying dryer.

[0203] Table 1

[0204]

[0205] Evaluation of mechanical properties (notched Charpy) and evaluation of soluble and insoluble washout of Examples 1 and 2 and Comparative Examples 1 to 4.

[0206] The results are provided in Table 2.

[0207] Table 2

[0208]

[0209] Plasticizer: n-butylbenzenesulfonamide (BBSA)

[0210] Rubber: Maleic anhydride grafted ethylene-octene copolymer

[0211] Additives: Carbon black, heat stabilizer and UV stabilizer

[0212] CNT: Porous carbon nanotube

[0213] Cold impact was performed on 80 mm x 10 mm x 4 mm size bars with V-notch according to ISO 179-1 :2010 / 1 eA (Charpy impact) on dry samples at a temperature of -40°C + / - 2°C under a relative humidity of 50% + / - 10%.

[0214] Soluble and insoluble washout:

[0215] The test consists of filling a tube with alcohol-containing FAM B finished oil at 60°C for 96 hours, then at 23°C for 24 hours, and then emptying and filtering into a beaker.

[0216] Alcohol-containing finished oil FAM B is described in standards DIN 51604-1 : 1982, DIN 51604-2: 1984 and DIN 51604-3: 1984.

[0217] In short, alcohol-containing finished oil FAM A is first prepared with a mixture of 50% toluene, 30% isooctane, 15% diisobutene and 5% ethanol, then FAM B is prepared by mixing 84.5% of FAM A with 15% of methanol and 0.5% of water.

[0218] FAM B totals 42.3% toluene, 25.4% isooctane, 12.7% diisobutene, 4.2% ethanol, 15% methanol and 0.5% water.

[0219] The dry filter is weighed (washout of insoluble) and, after evaporation of the filtered fuel, the residue is weighed (washout of soluble), each weighing (soluble and insoluble) being expressed in g / m 2 The pipe internal surface area is expressed.

[0220] Examples 1 and 2 provide the best compromise for the three properties (notched Charpy, washout of soluble and washout of insoluble) compared to Comparative Examples 1 to 4.

Claims

1. Use of a composition comprising at least one polyamide and clay, said polyamide having an average number of carbon atoms per nitrogen atom greater than 6, particularly greater than or equal to 7, particularly greater than or equal to 8, for preparing a tubular structure intended for use in the transport of fuels, particularly gasoline, particularly alcohols, said tubular structure comprising at least one layer (1) comprising said composition and having a reduced content of extractables, particularly oligomers, extracted from said fuel relative to an identical structure comprising the same composition but without the clay, The composition does not contain polyamides obtained by polycondensation of meta-xylylenediamine with dicarboxylic acids Cb among C4 to C36.

2. The method according to claim 1, wherein the composition does not contain carbon nanotubes.

3. Use according to claim 1 or 2, characterized in that the composition comprises 1 to 10% by weight of clay.

4. Use according to any one of claims 1 to 3, characterized in that the reduction of insoluble extractables is at least 50%, in particular at least 60%.

5. Use according to any one of claims 1 to 3, characterized in that the reduction of soluble extractables is at least 10%, in particular at least 15%.

6. Use according to any one of claims 1 to 3, characterized in that the reduction of insoluble extractables is at least 50%, in particular at least 60%, and the reduction of soluble extractables is at least 10%, in particular at least 15%.

7. The use according to any one of claims 1 to 6, characterized in that the composition comprises the following substances by weight: , in particular 40 to 98.9% of at least one polyamide having an average number of carbon atoms per nitrogen atom greater than 6, in particular greater than or equal to 7, in particular greater than or equal to 8, obtained by polycondensation: , preferably at least one amino acid from C10 to C18, more preferably from C10 to C12, or , preferably at least one lactam from C10 to C18, more preferably from C10 to C12, or , preferably C6 to C18, preferably C6 to C12, more preferably C10 to C12 at least one diamine Ca and C4 to C36, preferably C6 to C18, preferably C6 to C12, more preferably C10 to C12 at least one dicarboxylic acid Cb; The polycondensation of m-xylylenediamine and C4-C36 dicarboxylic acid Cb is not included; of clay; , in particular 1-30% of at least one functionalized polyolefin; , in particular 0.1-15% of at least one plasticizer; of carbon nanotubes; additives; The sum of all ingredients is 100% by weight.

8. Use according to any one of claims 1 to 7, characterized in that the polyamide is an aliphatic polyamide.

9. Use according to claim 8, characterised in that the aliphatic polyamide is selected from PA10, PA11, PA12, PA1010, PA1012, in particular PA11 and PA12.

10. The use according to any one of claims 1 to 9, characterized in that the composition has a mass fraction greater than 6 kJ / m 2 Impact resistance, measured according to ISO 179-1:2010 / 1eA (Charpy impact) on bars with V-notch dimensions 80 mm x 10 mm x 4 mm, at a temperature of -40°C + / - 2°C and at a relative humidity of 50% + / - 10% on dry samples.

11. Tubular structure for transporting fuels, in particular gasoline, in particular alcohols, comprising at least one layer (1) comprising a composition as defined in any one of claims 1 to 10.

12. Tubular structure according to claim 11, characterised in that it further comprises at least one barrier layer (2) chosen from EVOH or PPA, said layer (1) being in contact with the fuel.

13. Tubular structure according to claim 12, characterized in that there is at least one outermost layer (3) located above the barrier layer (2), said outer layer (3) mainly comprising at least one aliphatic polyamide or consisting of more than 75% aliphatic units, in particular said aliphatic polyamide having an average number of carbon atoms per nitrogen atom comprised between 9.5 and 18, advantageously between 11 and 18.

14. Tubular structure according to claim 12 or 13, characterized in that there is at least one layer (4) which mainly comprises at least one aliphatic polyamide or consists of more than 75% of aliphatic units, said aliphatic polyamide being chosen from: - polyamides, denoted A, having an average number of carbon atoms per nitrogen atom, denoted CA, comprised between 4 and 8.5, preferably between 4 and 7; - polyamides denoted B and wherein the average number of carbon atoms per nitrogen atom denoted CB is comprised between 7 and 10, preferably between 7.5 and 9.5; - polyamides, denoted C, having an average number of carbon atoms per nitrogen atom, denoted CC, comprised between 9 and 18, preferably between 10 and 18; Provided that, in the case where said layer (4) comprises at least three polyamides, at least one of those polyamides A, B or C is excluded, The layer (4) is located between the barrier layer (2) and the layer (1) and / or between the outer layer (3) and the barrier layer (2); or The layer (4) is an adhesive layer, the thickness of which is at most 15% of the structure (MLT).

15. Tubular structure according to claim 14, wherein there is a layer (4') which mainly comprises or consists of more than 75% of aliphatic units at least one aliphatic polyamide chosen from: - polyamides, denoted A, having an average number of carbon atoms per nitrogen atom, denoted CA, comprised between 4 and 8.5, preferably between 4 and 7; - polyamides denoted B and wherein the average number of carbon atoms per nitrogen atom denoted CB is comprised between 7 and 10, preferably between 7.5 and 9.5; - polyamides, denoted C, having an average number of carbon atoms per nitrogen atom, denoted CC, comprised between 9 and 18, preferably between 10 and 18; Provided that, in the case where said layer (4') comprises at least three polyamides, at least one of those polyamides A, B or C is excluded, or said layer (4') being an adhesive layer, the thickness of which is at most 15% of said structure (MLT), The at least polyamide of the layer (4') may be the same as or different from the polyamide of the layer (4); The layer (4') is located between the outer layer (3) and the barrier layer (2), and the adhesive layer (4) is located between the barrier layer (2) and the layer (1).

16. A composition comprising, by weight: , in particular 40 to 97.9% of at least one polyamide having an average number of carbon atoms per nitrogen atom greater than 6, in particular greater than or equal to 7, in particular greater than or equal to 8, obtained by the polycondensation of: , preferably at least one amino acid from C10 to C18, more preferably from C10 to C12, or , preferably at least one lactam from C10 to C18, more preferably from C10 to C12, or , preferably C6 to C18, preferably C6 to C12, more preferably C10 to C12 at least one diamine Ca and C4 to C36, preferably C6 to C18, preferably C6 to C12, more preferably C10 to C12 at least one dicarboxylic acid Cb, Excluding the polycondensation of m-xylylenediamine with C4 to C36 dicarboxylic acids Cb; of clay; at least one functionalized polyolefin; , in particular 0.1-15% of at least one plasticizer; of carbon nanotubes; at least one additive; The sum of all ingredients is 100% by weight.

17. The composition according to claim 16, characterized in that it is free of carbon nanotubes.

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