Polyamide molding composition with enhanced fire resistance

Abstract

The present invention relates to a polyamide molding composition comprising, consisting essentially of or consisting of: - between 15.0 wt% and 70.0 wt% of at least one polyamide (PA) selected in the group consisting of aliphatic polyamides, polyphthalamides (PPA) and combinations thereof, polyamide (PA) preferably exhibiting:  a melting temperature (Tm) of at least 250.0°C and a heat of fusion (Hm) of at least 30.0 J / g; and / or  a glass transition temperature (Tg) of at least 60.0°C;  Tm, Hm and Tg being measured by Differential scanning calorimetry (DSC) according to ASTM D3418, notably using a heating and cooling rate of 20°C / min; - between 20.0 wt% and 75.0 wt% of glass fibers (GFs) dispersed in the polyamide molding composition; - between 1.0 wt% and 30.0 wt% of at least one flame retardant (FR); and - optionally at least one additive (Add) other than the flame retardant (FR), notably selected from the group consisting of impact modifiers, tougheners, plasticizers, colorants, pigments, antistatic agents, dyes, lubricants, thermal stabilizers, light stabilizers, antioxidants, nucleating agents, polymer processing aids, anti-blocking agents, slip agents, antifogging agents, chemical blowing agents, nucleating agents and any combination thereof.

Description

POLYAMIDE MOLDING COMPOSITION WITH ENHANCED FIRE RESISTANCEThis application claims priority of US provisional application N° 63 / 674,879 filed on 24 July 2024, US provisional application N° 63 / 693,598 filed on 11 September 2024 and European patent application N° 24204818.9 filed on 4 October 2024, the content of which being entirely incorporated herein by reference for all purposes. In case of any incoherency between this application and one of the priority applications that would affect the clarity of a term or expression, it should be made reference to this application only.[TECHNICAL FIELD]

[0001] The present invention relates to a polyamide molding composition that can be used as a thermal insulation barrier (or thermal barrier).[TECHNICAL PROBLEM]

[0002] With the development of electric vehicles (EVs) and the need to decrease the weight of many components, the original equipment manufacturers (OEMs) are looking for battery enclosures and other parts of the battery that are made with polymeric materials.

[0003] Thermal runaway of lithium-ion cells occurs sometimes when the lithium-ion cells enter an uncontrollable self-heating state that may result in fire, smoke and extremely high temperatures while ejecting harmful substances.

[0004] Battery performance has continually presented challenges in EV efficiency. Battery enclosure systems play a critical role in mitigating the impact of thermal runaway, a risk associated with lithium-ion batteries. Any unwanted thermal runaway should be confined in a battery enclosure so as to avoid that the burst of heat and energy escapes into the rest of the vehicle. Moreover, due to the increased temperature of a battery cell undergoing a thermal runaway, the temperature of adjacent cells within the battery will also increase, which can lead to an instability and thermal runaway of the adjacent cells in a cascading way. The configuration of the battery may thus contain walls separating the cells or the packs of cells within the battery enclosure. The material of these walls and other parts of the battery enclosure should also withstand the thermal runaway and be resistant enough to confine the runaway.

[0005] The polymeric material should also preferably exhibit a combination of good mechanical properties, such as resistance to impact and tensile strength, and thermal resistance, notably in case of a thermal runaway.

[0006] There is therefore the need to develop a polymeric material used for the preparation of a battery enclosure and other parts of the battery that can withstand and contain any thermal runaway and resist to the dynamic stress triggered by the runaway.

[0007] The polymeric material should also be easily molded.

[0008] The invention and the polymeric material of the invention aim at solving this technical problem.[BACKGROUND OF THE INVENTION]

[0009] Flame resistant polymeric materials have been known for a long time but the materials developed do not aim at solving the problem of a dynamic thermal runaway.

[0010] CN 1 15785663 provides a halogen-free flame-retardant nylon material for battery pack shells comprising 40-67 parts of a polyamide 6 or 66, 20-30 parts of GF, 5-10 parts of modified melamine polyphosphate, 4-10 parts of aluminum diethyl hypophosphite, 0.1 -0.5 parts of a chain extender, 3-8 parts of toughening agent and 1-2 parts of other additives. The toughening agent is a polymer with maleic anhydride.

[0011] US 2014 / 0363654 A1 (EMS-Patent AG) discloses a polyamide molding composition consisting of at least one polyamide, glass fibers, where the arithmetic average of the length of these glass fibers in the polyamide molding composition is from 100 to 220 pm, at least one phosphinic salt and / or at least one diphosphinic salt, and optionally at least one additive, exhibiting V0 rating at 3.2 mm according to UL-94 (Underwriters Laboratories-94: Tests for flammability of plastic materials for parts in devices and appliances).

[0012] US 2012 / 029124 discloses a polymer composition comprising: at least one semi-aromatic polyamide having a melting point of at least 270° C; at least one organophosphorous compound selected from the group consisting of a phosphinic salt, a diphosphinic salt and condensation products thereof; and at least 0.01 wt%, based on the total weight of the composition, of calcium oxide. US 2012 / 029124 does not disclose any time of failure nor any size of the GFs in the polyamide composition.

[0013] US 2023 / 183454 discloses an electrical or electronic article comprising a semi-crystalline polyamide and glass fibers. US 2023 / 183454 does not disclose any time of failure nor any size of the GFs in the polyamide composition.

[0014] US 2023 / 183452 discloses a composition comprising a semi-crystalline polyamide and glass fibers. US 2023 / 183452 does not disclose any time of failure nor any size of the GFs in the polyamide composition.

[0015] EP 4191757 A1 discloses a thermal runaway protection film for a lithium ion battery, the film comprising at least one protection layer comprising at least one silicone and at least one silicate compound in an amount of at least 40 wt%, based on the total weight of the at least one protection layer. D6 does not disclose the composition of the invention.

[0016] US 2014 / 0275367 A1 (Cheil Industries Inc.) discloses adding polyphenylene sulfide to a reinforced polyamide composition, which exhibit satisfactory flame-retardant performances while reducing the amount of the flame retardant required.

[0017] US 10,435,540 B2 (SABIC) discloses another approach using pellets having a particular structure consisting of a core and a sheath, wherein a core contains glass fibers and an impregnating agent, and a sheath surrounding said core contains polypropylene and a mixture of an organic phosphate compound, an organic phosphoric acid compound and zinc oxide as flame retardants.

[0018] WO 2024 / 022878 discloses a battery pack and a battery enclosure. The polyamide molding composition of the invention is not disclosed.

[0019] US 2024 / 0059867 A1 discloses a device including a flame retardant comprising a polymer matrix of crosslinked an aliphatic polyketone.

[0020] US 2023 / 0058396 discloses a thermal barrier article comprising a core layer containing a plurality of fibers or a flame retardant foam, and a supplementary layer disposed on or integrated within the core layer, wherein the thermal barrier article is operatively adapted to survive or withstand at least one cycle of the Torch and Grit Test. See also US 2023 / 395281 .

[0021] US 2022 / 262539 discloses a multilayer material for use as a thermal insulation barrier in a rechargeable electrical energy storage system.

[0022] WO 2024 / 003632 discloses an inorganic thermal barrier coatings and articles containing the coatings that can be used as impact resistant thermal barriers in high temperature applications.

[0023] WO 2024 / 194225 discloses a polyamide molding composition.

[0024] US 2022 / 356328 (D1) discloses a polyamide-based composition comprising a long chain semiaromatic polyamide, a flame-retardant, phosphazene and a reinforcing agent. All examples are based on PA9T of Kuraray and glass fibers HP 3610 of PPG Industries (diameter 10 pm; length 4500 pm).

[0025] JP 2013 / 194196 (D2) disclose a polyamide resin composition comprising (a) 100 parts by weight of a polyamide resin obtained by polycondensing a diamine having as its main components 1 ,5- pentanediamine and an aliphatic diamine having 6 or more carbon atoms, and a dicarboxylic acid having as its main component terephthalic acid and / or a derivative thereof, and (b) 1 to 200 parts by weight of flat cross section glass fiber.[SUMMARY OF THE INVENTION]

[0026] The invention is as disclosed below and in the appended claims.

[0027] More precisions and details about the claimed subject-matters and about the invention are now provided below.

[0028] The various aspects, advantages, and features of the invention will be more readily understood and appreciated by reference to the detailed description and examples.[DEFINITIONS]

[0029] wt%: % by weight; mol%: % by mole.

[0030] When numerical ranges are indicated herein, the end-points of the ranges (even of open-ended ranges such as those comprising "at least" or "at most") are included.

[0031] An aliphatic polyamide is a polyamide wherein at least 50.0 mol%, preferably at least 90.0 mol%, preferably at least 95.0 mol%, preferably at least 99.0 mol%, of the recurring units are of formula -C(=O)-Alk-NH- (I) and / or -C(=O)-Alk-C(=O)-NH-Alk’-NH- (II) where Aik and Aik’ are selected in the group of linear and branched C4-C18 alkylene groups. Examples of aliphatic polyamide are PA66 (with recurring units of formula (II) with Aik = -(CH2)4- and Aik’ = -(CH2)B-) and PA11 (with recurring units of formula (I) with Aik = -(CH2)IO-).

[0032] A polyphthalamide (PPA) is a polyamide in which the residues of terephthalic acid or isophthalic acid or a combination of the two comprise at least 50.0 mol% of the dicarboxylic acid part of the repeating structural units in the polymer chain. This definition is in line with ASTM D883-11 .

[0033] The proportion of recurring units in a polymer are given in mol% and relative to the total proportion of recurring units in the polymer.

[0034] A polyamide disclosed herein is sometimes defined by reference to the contents of the dicarboxylic acid component and of the diamine component that are used for the preparation of a polyamide. In this situation, the proportion of a dicarboxylic acid in the dicarboxylic acid component is expressed in mol% and relative to the total number of moles of dicarboxylic acid(s) in the dicarboxylic acid component and the proportion of a diamine in the diamine component is expressed in mol% and relative to the total number of moles of diamine(s) in the diamine component. These proportions of monomers indicated correspond to and can be translated into the proportions of monomers present in the polyamide in polymerized form after polymerization. Moreover, according to a preferred embodiment, the dicarboxylic acid component consists of indicated dicarboxylic acids(s) and the diamine component consists of the indicated diamine(s).

[0035] In the present application, unless otherwise indicated, any specific embodiment or technical feature relating to one of the subject-matters of the invention is applicable to and interchangeable with another embodiment or technical feature relating also to said subject matter and disclosed elsewhere in the application. Likewise, unless otherwise indicated, any specific embodiment or technical feature relating to one of the subject-matters of the invention (e.g. polyamide molding composition) is applicable to or interchangeable with another embodiment or technical feature (i) relating to another subject-matter (e.g. use) of the invention and (ii) disclosed elsewhere in the application.

[0036] The parameters of the distribution relating to the glass fibers dispersed in the polyamide molding composition of the invention are determined according to method disclosed in the application (§ "Method for measuring the parameters of the distributions of the sizes of the GFs"), more particularly according to the method disclosed in the Experimental Section.[DETAILED DESCRIPTION OF THE INVENTION]

[0037] About the polyamide molding composition

[0038] The polyamide molding composition of the invention is disclosed in any one of claims 1-44. The polyamide molding composition of the invention comprises, consists essentially of or consists of: between 15.0 wt% and 70.0 wt% of at least one polyamide (PA) selected in the group consisting of aliphatic polyamides, polyphthalamides (PPA) and combinations thereof, the polyamide (PA) preferably exhibiting:■ a melting temperature (Tm) of at least 250.0°C and a heat of fusion (Hm) of at least 30.0 J / g; and / or■ a glass transition temperature (Tg) of at least 60.0°C; between 20.0 wt% and 75.0 wt% of glass fibers (GFs) dispersed in the polyamide molding composition; between 1 .0 wt% and 30.0 wt% of at least one flame retardant (FR); and optionally at least one additive (Add) other than the flame retardant (FR), notably selected from the group consisting of impact modifiers, tougheners, plasticizers, colorants, pigments, antistatic agents, dyes, lubricants, thermal stabilizers, light stabilizers, antioxidants, nucleating agents, polymer processing aids, anti-blocking agents, slip agents, antifogging agents, chemical blowing agents, nucleating agents and any combination thereof; these proportions in wt% being provided relative to the total weight of the polyamide molding composition.

[0039] The proportions of the components of the polyamide molding composition, as given herein, are expressed in wt% and relative to the total weight of composition (C). The sum of proportions of the components of composition (C) is equal to 100 wt%.

[0040] The glass fibers (GFs) are present in the molding composition as being dispersed and blended with the other components of the polyamide molding composition. All components of the polyamide molding composition {e.g. polyamide(s) (PA), GFs, FR(s) and additive(s) (Add) (if any)) are typically blended.

[0041] According to an embodiment of the present invention, the proportions of the components are the following: between 35.0 wt% and 65.0 wt% of at least one polyamide (PA) selected in the group consisting of aliphatic polyamides, polyphthalamides (PPA) and combinations thereof, the polyamide (PA) exhibiting:■ a melting temperature (Tm) of at least 250.0°C and a heat of fusion (Hm) of at least 30.0 J / g; and / or■ a glass transition temperature (Tg) of at least 60.0°C; between 20.0 wt% and 60.0 wt% of glass fibers (GFs) dispersed in the polyamide molding composition; between 1 .0 wt% and 30.0 wt% of at least one flame retardant (FR); and optionally at least one additive (Add) other than the flame retardant (FR) and other than the glass fibers (GF), notably selected from the group consisting of impact modifiers, tougheners, plasticizers, colorants, pigments, antistatic agents, dyes, lubricants, thermal stabilizers, light stabilizers, antioxidants, nucleating agents, polymer processing aids, antiblocking agents, slip agents, antifogging agents, chemical blowing agents, nucleating agents and any combination thereof; these proportions in wt% being provided relative to the total weight of the polyamide molding composition.

[0042] The proportion of the GFs dispersed in the polyamide molding composition is between 20.0 and 75.0 wt%. According to an embodiment of the present invention, this proportion is:- between 20.0 and 60.0 wt%; or- between 30.0 and 60.0 wt%; or- between 30.0 and 55.0 wt%; or- between 30.0 and 50.0 wt%.

[0043] The proportion of the FR(s) in the polyamide molding composition is between 1 .0 and 30.0 wt%. According to an embodiment of the present invention, this proportion is between 5.0 and 20.0 wt% or between 8.0 and 20.0 wt% or between 10.0 and 20.0 wt%.

[0044] The proportion of the polyamide(s) (PA) in the polyamide molding composition is between 15.0 wt% and 70.0 wt%. According to an embodiment of the present invention, this proportion is:- between 20.0 wt% and 65.0 wt%; or- between 30.0 wt% and 65.0 wt%; or- between 35.0 wt% and 65.0 wt%; or- between 35.0 wt% and 60.0 wt%; or- preferably between 35.0 wt% and 55.0 wt%.

[0045] The proportion of additive(s) (Add) is typically between 0 and 15.0 wt% or between 0 and 10.0 wt% .

[0046] According to an embodiment of the present invention, the proportions of the components of the polyamide molding composition are preferably the following: between 20.0 wt% and 65.0 wt% of at least one polyamide (PA) as defined herein: between 20.0 wt% and 60.0 wt% of the glass fibers (GFs) as defined herein;between 1.0 wt% and 30.0 wt%, preferably between 5.0 and 20.0 wt%, more preferably between 8.0 and 20.0 wt%, of at least one flame retardant (FR) as defined herein; and optionally at least one additive (Add) other than the flame retardant (FR), notably selected from the group consisting of impact modifiers, tougheners, plasticizers, colorants, pigments, antistatic agents, dyes, lubricants, thermal stabilizers, light stabilizers, antioxidants, nucleating agents, polymer processing aids, anti-blocking agents, slip agents, antifogging agents, chemical blowing agents, nucleating agents and any combination thereof.

[0047] According to another embodiment of the present invention, the proportions of the components of the polyamide molding composition are more preferably the following: between 35.0 wt% and 55.0 wt% of at least one polyamide (PA) as defined herein; between 30.0 wt% and 50.0 wt% of the glass fibers (GFs) as defined herein; between 1.0 wt% and 30.0 wt%, preferably between 5.0 and 20.0 wt%, more preferably between 8.0 and 20.0 wt%, of at least one flame retardant (FR) as defined herein; and optionally at least one additive (Add) other than the flame retardant (FR), notably selected from the group consisting of impact modifiers, tougheners, plasticizers, colorants, pigments, antistatic agents, dyes, lubricants, thermal stabilizers, light stabilizers, antioxidants, nucleating agents, polymer processing aids, anti-blocking agents, slip agents, antifogging agents, chemical blowing agents, nucleating agents and any combination thereof.

[0048] The polyamide molding composition may comprise one or more polyamide (PA).

[0049] According to one embodiment of the present invention, the polyamide molding composition comprises only one polyamide (PA) as defined herein.

[0050] According to another embodiment, the polymeric component of the polyamide molding composition consists of the one or more polyamides (PA).

[0051] Distribution of the GFs dispersed in the polyamide molding composition

[0052] The GF(s) are dispersed in the polyamide molding composition and have different lengths. The polyamide molding composition is also characterized by a specific distribution of the size of these GFs. This distribution corresponds to the distribution of the lengths of the GFs as dispersed in the polyamide molding composition.

[0053] The polyamide molding composition of the invention can be characterized by set of parameters (S1) or (S2) or by sets of parameters (S1) and (S2), these sets being as defined herein.

[0054] Number-weighted distribution of the length of the GFs

[0055] The number-weighted distribution provides the numbers of GFs having a specified length L. In a number-weighted distribution, each GF is given equal weighting irrespective of its length.

[0056] From this number-weighted distribution, it is possible to calculate the arithmetic average length of the GFs. Lav is the arithmetic average length according to the following formula:where:- Li is the length of the ithfiber;- n is the number of fibers measured.Moreover, from this number-weighted distribution, it is observed that the polyamide molding composition is characterized by a significant proportion of GFs having a certain length L.

[0057] The polyamide molding composition can be characterized by set of parameters (S1) comprising parameter (i) and parameter(s) (iia) and / or (iib):

[0058] (Lav) is typically between 800 pm and 3000 pm, preferably between 900 pm and 1500 pm.

[0059] According to an embodiment, (iia) the proportion of the GFs having a length higher than 1500 pm is at least 45.0% and / or (iib) the proportion of the GFs having a length higher than 2500 pm of at least 35.0%.

[0060] According to an embodiment, (iia) the proportion of the GFs having a length higher than 1500 pm is at least 50.0%, preferably at least 55.0%, preferably at least 60.0%.

[0061] According to an embodiment, (iib) the proportion of the GFs having a length higher than 2500 pm of at least 40.0%.

[0062] According to an embodiment, (iia) the proportion of the GFs having a length higher than 1500 pm is at most 70.0% and / or (iib) the proportion of the GFs having a length higher than 2500 pm of at most 50.0%.

[0063] Polyamide molding composition typically exhibits (iic) a proportion of the GFs having a length higher than 400 pm of at least 80.0% and / or (iid) a proportion of the GFs having a length higher than 500 pm of at least 75.0%.

[0064] According to an embodiment, (iic) the proportion of the GFs having a length higher than 400 pm is at least 85.0% and / or (iid) the proportion of the GFs having a length higher than 500 pm is at least 80.0%.

[0065] Typically, from this number-weighted distribution, it appears that at least 90.0% of the GFs have a length lower than or equal to 9000 pm, preferably lower than or equal to 2500 pm.

[0066] Volume-weighted distribution of the length of the GFs

[0067] The volume-weighted distribution provides the volume (or weight) of the GFs having a specified length L. Here, the contribution of each GF in the distribution relates to its volume. The volume Vi of the ithfiber is taken as: Vi = (TC r2) x Li where r is the radius of the GFs. The radius of the GFs used for the preparation of the polyamide molding composition is taken as being the same for all the GFs. Whereas in a number-weighted distribution, the % are expressed in number, in a volume-weighted distribution, the % are expressed in volume.

[0068] To be noted: the diameter is known and corresponds to the diameter of the GFs used as starting material used for the preparation of the polyamide molding composition.

[0069] From the volume-weighted distribution, it is possible to calculate the following average length Lpof the GFs with the following equation:where:- ni is the number of glass fibers of length Li;- n is the number of glass fibers measured.

[0070] Moreover, from this volume-weighted distribution, it is observed that the polyamide molding composition is characterized by a significant proportion of GFs having a certain length L.

[0071] The polyamide molding composition can be characterized by set of parameters (S2) comprising parameter (i) and parameter(s) (iia) and / or (iib):

[0072] (LP) is between 1800 pm, this value being excluded, and 4000 pm. Thus, (LP) > 1800 pm. (LP) is typically between 2000 pm and 3500 pm, preferably between 2000 pm and 3000 pm, preferably between 2000 and 3000 pm, preferably between 2000 and 2700 pm.

[0073] According to an embodiment, (iia) the proportion of the GFs having a length higher than 1500 pm is at least 60.0%.

[0074] According to an embodiment, (iib) the proportion of the GFs having a length higher than 2500 pm is at least 50.0%.

[0075] According to an embodiment, (iia) the proportion of the GFs having a length higher than 1500 pm of at least 80.0% and / or (iib) a proportion of the GFs having a length higher than 2500 pm of at least 65.0%.

[0076] According to an embodiment, (iia) the proportion of the GFs having a length higher than 1500 pm is at least 85.0% and / or (iib) a proportion of the GFs having a length higher than 2500 pm is at least 70.0%.

[0077] According to an embodiment, (iia) the proportion of the GFs having a length higher than 1500 pm is at most 95.0% and / or (iib) the proportion of the GFs having a length higher than 2500 pm of at most 85.0%.

[0078] Polyamide molding composition typically exhibits (iic) a proportion of the GFs having a length higher than 400 pm of at least 99.0% and / or (iid) a proportion of the GFs having a length higher than 500 pm of at least 98.0%.

[0079] Method for measuring the parameters of the distributions of the sizes of the GFs

[0080] The method for measuring the parameters of the distributions of the sizes of the GFs that are used herein to characterize the polyamide molding composition of the invention is now explained.

[0081] The distribution of the GFs is generally obtained by observing with a microscope a statistically significant number n {e.g. at least 5000) of glass fibers separated from the polyamide molding composition.

[0082] The observation and the determination of the distributions may be performed automatically, as is disclosed for instance in WO 2008 / 033789.

[0083] Both the number-weighed and the volume-weighted distributions are obtained after the separation of the dispersed GFs from the polyamide molding composition. This separation may be performed according to a ash method (a) or a chemical method (b), more specifically according to any one of the methods specified herein.

[0084] Ash method (a)

[0085] The separation of the GFs may be performed by any one of the ash methods disclosed herein.

[0086] The separation of the GFs may be performed by the ash method (a) which comprises the following steps:(a1) heating a sample of the polyamide molding composition in a furnace; and(a2) recovering the glass fibers (GFs).

[0087] The temperature at which step (a1) is performed should preferably allow the decomposition of polymeric component without degrading the glass fibers (GFs). It is preferable that the decomposition takes place smoothly without degradation of the GFs.

[0088] The temperature at which step (a1) is performed is generally at least 500°C.

[0089] The duration of step (a1) should be long enough to allow the decomposition of the polymeric component. The step (a1) is generally implemented until the weight of the burnt sample no longer evolves.

[0090] A muffle furnace can be used for the ash method (a).

[0091] Method (a) is preferably according to one of the two following conditions disclosed below:

[0092] The separation of the GFs is preferably performed by the ash method (a) disclosed in ISO 22314:2006(E). It may be noted that the ash method disclosed in ISO 22314:2006(E) may be adapted with a variation of the temperature at which the sample is heated.

[0093] Any one of the ash methods disclosed herein (Ze. method (a) or method (a) under the specific conditions disclosed herein), notably the ash method disclosed in the Experimental Section, may be used in the context of the present invention.

[0094] Chemical method (b)

[0095] The separation of the GFs may be performed by any one of the chemical methods disclosed herein.

[0096] The separation may also be performed by the chemical method (b) which comprises the following steps:(b1) heating a dispersion of the sample in a solution of sulfuric acid; and(b2) recovering the glass fibers.

[0097] Step (b1) is performed until the polyamide molding composition dissolves in an acidic solution.A concentrated solution {e.g. at least 98.0 wt%) is preferably used. The temperature at which step (b1) is performed is at least 200 °C.

[0098] Method (b) may more particularly be the following one:

[0099] Any one of the chemical methods disclosed above (i.e. method (b) or method (b) under the specific conditions disclosed) may be used in the context of the present invention.

[0100] With the glass fibers (GFs) isolated by either an ash method (a) or a chemical method (b), the glass fibers can be dispersed into a plastic petri dish using low pressure compressed air to facilitate dispersion. The glass fibers are then imaged on an optical microscope with inverted lighting, while adjusting the image magnification depending on the length of glass fibers. The glass fibers are then observed, the lengths are measured with the microscope and the fiber length distribution is reported in a histogram.

[0101] According to an embodiment of the present invention, the glass fibers (GF) have a diameter d of 5.0 pm or more, preferably 6.0 pm or more. In some particular embodiments, the glass fibers (GF) have a diameter d of from 5.0 pm to 20.0 pm. In other particular embodiments, the glass fibers (GF) have a diameter d of from 6.0 pm to 15.0 pm.

[0102] The morphology of the glass fibers is not particularly limited. The glass fibers can have a circular cross-section (‘round glass fiber’) or a non-circular cross-section. Examples of suitable flat glass fibers include, but are not limited to, glass fibers having oval, elliptical and rectangular cross sections. For the glass fibers not having a circular cross-section, the diameter d that is mentioned herein is the equivalent diameter which is the diameter of a circle having the same surface as the surface of the crosssection of the glass fibers having a non-circular cross-section.

[0103] Time of failure (tp)

[0104] As mentioned above, the polymeric molding composition needs to be resistant enough to the thermal stress triggered by a thermal runaway. The longer the time of resistance to the thermal stress, the better for containing the thermal runaway. The resistance to thermal stress was measured according to the two tests described below.

[0105] UL Solutions (https: / / www.ul.com / ) is a recognized certification company that provides standards and regulations. UL Solutions have developed the “Torch-and-Grit” (TaG) test which is disclosed in UL2596 “ Test Method for Thermal and Mechanical Performance of Battery Enclosure Materials” and which corresponds to the dynamic stresses found in an actual automotive battery thermal runaway event.

[0106] The polyamide molding composition is characterized by a time-to-failure (tp) of at least 90.0 s, tp being measured according to the Torch-and-Grit” (TaG) test disclosed in UL 2596, issue N°2 released on 8 September 2023, the sample having notably a thickness of 3 mm. tp under these conditions is typically at most 190.0 s.

[0107] GMW-18435 is a test that can be referred to as "Abusive Flame Test Procedure of Thermal Barrier Materials" edition 09 / 01 / 2021. The polyamide molding composition of the invention can also be characterized by a time-to-failure (tp 73) of at least 100 s, preferably at least 120 s, tp 73 being the time until the back surface of a plaque (152mm X 152mm X 2mm) is damaged under GMW-18435 (type 1 ; with no carbon steel plate backing assembly).

[0108] Mechanical properties

[0109] The polyamide molding composition of the invention exhibits an impact strength (notched Izod; room temperature; measured according to ISO 180; specimen size: type 1A bar) of at least 28.0 kJ / m2, preferably at least 30.0 kJ / m2. This property is typically at most 50.0 kJ / m2or at most 45.0 kJ / m2.

[0110] The polyamide molding composition of the invention typically exhibits a tensile strength at break (speed: 5 mm / min; measured according to ISO 527; specimen size: type 1A bar) of at least 200 MPa. This property is typically at most 250 MPa.

[0111] Polyamide (PA)

[0112] The polyamide (PA) and the polyamide molding composition preferably exhibit good thermal resistance even in normal conditions. Polyamide (PA) exhibits:■ a melting temperature (Tm) of at least 250.0°C and a heat of fusion (Hm) of at least 30.0 J / g; and / or■ a glass transition temperature (Tg) of at least 60.0°C.

[0113] Polyamide (PA) is selected in the group consisting of aliphatic polyamides, polyphthalamides (PPA) and combinations thereof.

[0114] Tm, Hm and Tg are measured by Differential scanning calorimetry (DSC) according to ASTM D3418, notably using a heating and cooling rate of 20°C / min.

[0115] According to a preferred embodiment of the present invention, the polyamide (PA) exhibits: a melting temperature (Tm) of at least 295.0°C, preferably at least 300.0°C, preferably at least 310.0°C; and a heat of fusion (Hm) of at least 35.0 J / g, preferably at least 40.0 J / g, preferably at least 50.0 J / g.

[0116] Tmis generally at most 340.0°C.

[0117] Hm is generally at most 80.0 J / g.

[0118] The polyamide (PA) preferably exhibits a glass transition temperature (Tg) of at least 60.0°C, preferably at least 90.0°C, preferably at least 100.0°C. Tgis preferably at least 120.0°C, preferably at least 130.0°C. Tgis generally no more than 170.0°C.

[0119] Polyphtalamide (PPA)

[0120] According to a preferred embodiment of the present invention, the polyamide (PA) is a polyphthalamide (PPA). Details about some PPAs that can be used in the present invention are given below.

[0121] According to embodiment, the polyamide (PA) comprises at least 95.0 mol% of recurring units (RPA) resulting from the condensation of: a dicarboxylic acid component (A) comprising (i) at least one phthalic acid selected from the group consisting of isophthalic acid (I), terephthalic acid (T) and combination of I and T, and (ii)optionally at least one dicarboxylic acid (DI) of formula (I) HOOC-Ri-COOH, where R1 is selected from the group consisting of a C2-C18 linear or branched alkylene group, a CB-CIS cycloalkylene group and combination thereof; and a diamine component (B) comprising at least one diamine of formula (II) H2N-R2-NH2, where R2 is selected from the group of a C4-C18 linear or branched alkylene group, a divalent radical derived from Z? / s(anninomethyl) cyclohexane selected from the group consisting of 1 ,3-BAC, 1 ,4- BAC and combination thereof.

[0122] 1 ,3-BAC is 1 ,3- / ?Zs(aminomethyl) cyclohexane of formula:Z? / s(aminomethyl) cyclohexane of formula:

[0123] The dicarboxylic acid component (A) more particularly consists essentially of or consists of: (i) at least one phthalic acid selected from the group consisting of isophthalic acid (I), terephthalic acid (T) and combination of I and T and (ii) optionally at least one dicarboxylic acid (DI) of formula (I) HOOC- Ri-COOH where R1 is selected from the group consisting of a C2-C18 linear or branch alkylene group, a CB-CIS cycloalkylene group and combination thereof where the expression "consist essentially" means in the context of the dicarboxylic acid component (A) that the dicarboxylic acid component (A) consists of:(j) the phthalic acid(s) and the dicarboxylic acid(s) (DI) of formula (I); and(jj) up to 1.5 mol%, preferably up to 1.0 mol%, preferably up to 0.5 mol%, of at least one dicarboxylic acid not belonging to the dicarboxylic acids listed in (j).

[0124] The diamine component (B) more particularly consists essentially of or consists of at least one diamine of formula (II) H2N-R2-NH2 where R2 is selected from the group of a C4-C18 alkylene, a divalent radical derived from Z? / s(aminomethyl) cyclohexane (BAG) selected from the group consisting of 1 ,3-BAC, 1 ,4-BAC and combination thereof, where the expression "consist essentially" means in the context of the diamine component (B) that the diamine component (B) consists of:(j) the diamine(s) of formula (II) H2N-R2-NH2 ; and(jj) up to 1 .5 mol%, preferably up to 1 .0 mol%, preferably up to 0.5 mol%, of at least one diamine not belonging to the diamines listed in (j).

[0125] R1 is more particularly selected from the group consisting of a C4-C8 alkylene group, a cycloalkylene group and combination thereof.

[0126] R2 is more particularly selected from the group consisting of a C4-C8 alkylene group, a divalent radical derived from Z? / s(aminomethyl) cyclohexane and combination thereof.

[0127] According an embodiment, the polyamide (PA) comprises at least 95.0 mol% of recurring units (RPA) formed from the condensation of a dicarboxylic acid component (A) and a diamine component (B), where: the dicarboxylic acid component (A) consists essentially of or consists of:■ between 90.0 mol% and 100 mol% of terephthalic acid,■ between 0 mol% and 10.0 mol% of a dicarboxylic acid (DI) selected from the group consisting of C@-Ci8 aliphatic dicarboxylic acid of formula HOOC-(CH2)n-COOH where n is an integer, isophthalic acid and combination thereof; and■ between 0 mol% and 10.0 mol% of 1 ,4-cyclohexanedicarboxylic acid,■ where mol% is relative to the total number of moles of dicarboxylic acids in the dicarboxylic acid component (A) and where the expression "consist essentially" means in the context of the dicarboxylic acid component (A) that the dicarboxylic acid component (A) consists of:(j) terephthalic acid, the dicarboxylic acid(s) (DI), the 1 ,4- cyclohexanedicarboxylic acid, with the proportions indicated; and(jj) up to 1.5 mol%, preferably up to 1.0 mol%, preferably up to 0.5 mol%, of at least one dicarboxylic acid not belonging to the dicarboxylic acids listed in (j); the diamine component (B) consists essentially of or consists of:■ between 55.0 mol% and 75.0 mol% of one or more C4-C8 aliphatic diamines;■ between 25.0 mol% and 45.0 mol% of an aliphatic diamine selected from the group consisting of 1 ,9-nonanediamine, 1 ,10-decanediamine and combination thereof;■ between 0 mol% and 10.0 mol% of a Z? / s(aminomethyl) cyclohexane selected from the group consisting of 1 ,3-BAC, 1 ,4-BAC and combination thereof;■ where mol% is relative to the total number of moles of diamines in the diamine component (B) and where the expression "consist essentially" means in the context of the diamine component (B) that the diamine component (B) consists of:(j) the C4-C8 aliphatic diamine(s), the aliphatic diamine selected from the group consisting of 1 ,9-nonanediamine, 1 ,10-decanediamine and combination thereof, the Z? / s(aminomethyl) cyclohexane(s), with the proportions indicated; and(jj) up to 1.5 mol%, preferably up to 1.0 mol%, preferably up to 0.5 mol%, of at least one diamine not belonging to the diamines listed in (j); wherein the Z? / s(aminomethyl) cyclohexane or the 1 ,4-cyclohexanedicarboxylic acid or both exhibit a proportion of greater than 0.5 mol% in respectively in the dicarboxylic acid component (A) and in thediamine component (B). The polyamide according to this embodiment is referred to as polyamide (PA1). Examples of polyamide according to this definition can be found in WO 2021 / 03705.

[0128] According to an embodiment, polyamide (PA) comprises at least 95.0 mol% of recurring units (RPA) formed from the polycondensation of a dicarboxylic acid component (A) and a diamine component (B), where: the dicarboxylic acid component (A) consist essentially of or consists of terephtalic acid, where the expression "consist essentially" means in the context of the dicarboxylic acid component (A) that the dicarboxylic acid component (A) consists of (j) terephthalic acid; and (jj) up to 1 .5 mol%, preferably up to 1 .0 mol%, preferably up to 0.5 mol%, of at least one dicarboxylic acid distinct from terephthalic acid; the diamine component (B) consist essentially of or consists of:■ between 55.0 mol% and 75.0 mol% of one or more C4-C8 aliphatic diamines;■ between 25.0 mol% and 45.0 mol% of an aliphatic diamine selected from the group consisting of 1 ,9-nonanediamine, 1 ,10-decanediamine and combination thereof;■ between 0.5 mol% and 10.0 mol% of a Z? / s(aminomethyl) cyclohexane selected from the group consisting of 1 ,3-BAC, 1 ,4-BAC and combination thereof;■ where mol% is relative to the total number of moles of diamines in the diamine component (B) and where the expression "consist essentially" means in the context of the diamine component (B) that the diamine component (B) consists of:(j) the C4-C8 aliphatic diamine(s), the aliphatic diamine selected from the group consisting of 1 ,9-nonanediamine, 1 ,10-decanediamine and combination thereof, the Z? / s(aminomethyl) cyclohexane(s), with the proportions indicated; and(jj) up to 1.5 mol%, preferably up to 1.0 mol%, preferably up to 0.5 mol%, of at least one diamine not belonging to the diamines listed in (j).The polyamide according to this embodiment is referred to as polyamide (PA2). Examples of polyamide according to this definition can be found in WO 2021 / 03705.

[0129] According to an embodiment, polyamide (PA) comprises at least 95.0 mol% of recurring units (RPA) formed from the polycondensation of a dicarboxylic acid component (A) and a diamine component (B), where: the dicarboxylic acid component (A) consists essentially of or consists of:■ between 90.0 mol% and 99.0 mol% of terephthalic acid,■ between 1.0 mol% and 10.0 mol% of 1 ,4-cyclohexanedicarboxylic acid,■ where mol% is relative to the total number of moles of dicarboxylic acids in the dicarboxylic acid component (A) and where the expression "consist essentially" means in the context of the dicarboxylic acid component (A) that the dicarboxylic acid component (A) consists of:(j) terephthalic acid and the 1 ,4-cyclohexanedicarboxylic acid, with the proportions indicated; and(jj) up to 1.5 mol%, preferably up to 1.0 mol%, preferably up to 0.5 mol%, of at least one dicarboxylic acid not belonging to the dicarboxylic acids listed in (j); where the diamine component (B) consist essentially of or consists of:■ between 50.0 mol% and 90.0 mol% of one or more C4-C8 aliphatic diamines;■ between 10.0 mol% and 50.0 mol% of a Z? / s(aminomethyl) cyclohexane selected from the group consisting of 1 ,3-BAC, 1 ,4-BAC and combination thereof;■ where mol% is relative to the total number of moles of diamines in the diamine component (A) and where "consist essentially" means that diamine component (A) consists of the C4-C8 aliphatic diamine(s), the £> / s(ami nomethyl) cyclohexane(s) with the indicated proportions and up to 1.5 mol%, preferably up to 1.0 mol%, preferably up to 0.5 mol%, of an additional diamine other than the C4-C8 aliphatic diamine(s) and the Z? / s(aminomethyl) cyclohexane.This polyamide is referred to as polyamide (PA3). Examples of polyamide according to this definition can be found in WO 2020 / 229210.

[0130] According to an embodiment, notably for polyamide PA1 , PA2 and PA3, the C4-C8 aliphatic diamine present in the diamine component (B) consists of 1 ,6-diaminohexane (aka hexamethylenediamine).

[0131] In the context of the present invention, polyamide (PA) is more particularly selected from the group consisting of:PA 66;- 9T;10T;6T / 6I / 66;- 6T / 66;6T / 6I;6T / 10T;6T / 10T / BACT, where BAG is 1 ,3-BAC and / or 1 ,4-BAC, preferably 1 ,3-BAC;6T / BACT / 66 / BAC6, where BAG is 1 ,3-BAC and / or 1 ,4-BAC, preferably 1 ,3-BAC; 6T / 10T / 6.CHDA / 10.CHDA where CHDA is 1 ,4-cyclohexanedicarboxylic acid; and 6T / 9T / 6.CHDA / 9.CHDA where CHDA is 1 ,4-cyclohexanedicarboxylic acid; a combination thereof.

[0132] All polyamides mentioned herein are prepared by polycondensation. This polymerization technique comprises a step in which a reaction mixture comprising all the monomers is heated at atemperature sufficient to induce the formation of amide bonds. The temperature at which the reaction mixture is heated is generally at least 200°C, even preferably at least 250°C. The conditions provided in the experimental section of EP 4021959 B1 can be followed or be used as guidelines for the preparation of polyamides.

[0133] Suitable polyamides for the preparation of the polyamide molding composition are commercially available under the trade name of AMODEL® from Solvay Specialty Polymers USA, LLC.

[0134] The polyamide (PA) disclosed herein, notably polyamide (PA1), (PA2), (PA3) or any one of the polyamides disclosed above, preferably exhibits the following properties:- a melting temperature (Tm) of at least 300°C;- a heat of fusion (Hm) of at least 30.0 J / g, preferably between 30.0 and 80.0 J / g;- a glass transition temperature (Tg) of at least 100°C.

[0135] Conditions provided in the Experimental Section are conveniently used for determining the thermal properties of polyamide (PA).

[0136] Flame retardant (FR)

[0137] The polyamide molding composition comprises also at least one FR.

[0138] The FR is preferably halogen-free.

[0139] The FR is preferably an organophosphorous compound. In another embodiment, the FR comprises an organophosphorous compound and a flame-retardant synergist. In the context of the present invention, the organophosphorous compound is notably any one of the organophosphorous compound disclosed herein.

[0140] In a particular embodiment of the present invention, the FR is or comprises at least one organophosphorous compound selected from the group consisting of phosphinic salts (phosphinate), diphosphinic salts (diphosphinate) and combination thereof.

[0141] In a particular embodiment of the present invention, the FR is or comprises at least one organophosphorous compound selected from the group consisting of phosphinic salts (phosphinate) of formula (a), diphosphinic salts (diphosphinate) of formula (b) and combination thereof:(b), wherein R7and R8, identical or different, are preferably C-I-CB alkyl, linear or branched, or aryl; R9is Ci- C10 alkylene, linear or branched, CB-CIO arylene, alkylarylene or arylalkylene; M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ge, Bi, Sr, Mn, Li, Na, K or a protonated nitrogen base; m is 1 to 4; n is 1 to 4; and x is 1 to 4.

[0142] m, n and x are typically such that the molecules of formula (a) or (b) are neutral.

[0143] In formulae (a) and (b), M is preferably Ca, Al or Zn; the protonated nitrogen bases are preferably protonated bases of ammonia, melamine, triethanolamine, in particular NH4+; R7and R8, identical or different, are preferably CI-CB alkyl, linear or branched and / or phenyl, particularly preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl and / or phenyl. R9is preferably methylene, ethylene, n-propylene, isopropylene, n-butylene, tert-butylene, n-pentylene, n-octylene, or n-dodecylene. In a particular embodiment, R9is phenylene or naphthylene.

[0144] According to an embodiment of the present invention,- M is Mg, Ca, Al or Zn;- m is 2 or 3; and- n is 1 or 3; and- x is 1 or 2.

[0145] The FR is more particularly an organo-phosphorous of formula (a).

[0146] Phosphinates are preferred as organophosphorous compound. Aluminum phosphinates, calcium phosphinates, and zinc phosphinates are particularly preferred. Among aluminum phosphinates, aluminium ethylmethylphosphinate and aluminium diethylphosphinate are preferred. In a particularly preferred embodiment, the FR is aluminium diethylphosphinate.

[0147] The following FRs may be used in the molding composition: a mixture of 80 wt% of aluminum salt of diethylphosphinic acid and 20 wt% of aluminium phosphate; aluminum salt of diethylphosphinic acid.

[0148] In an embodiment of the present invention, the FR comprises a (di)phosphinate salt and a nitrogen-containing synergist.

[0149] Synergistic combinations of the specified phosphinates with nitrogen-containing compounds which have more effective action than the phosphinates alone in various polymers are also in accordance with the invention.

[0150] The nitrogen-containing synergists preferably comprise benzoguanamine, f / 7s(hydroxy ethyl) isocyanurate, allantoin, glycoluril, melamine, melamine cyanurate, dicyandiamide, guanidine, carbodiimides, etc.

[0151] The nitrogen-containing synergists preferably comprise condensation products of melamine. By way of example, condensation products of melamine are melem, melam, or melon.

[0152] The nitrogen-containing synergist may comprise reaction products of melamine with phosphoric acid or with condensed phosphoric acids. By way of example, these are dimelamine phosphate, dimelamine pyrophosphate, melamine phosphate, melamine pyrophosphate, melamine polyphosphate, melam polyphosphate, melon polyphosphate, and melem polyphosphate, and mixed polysalts.

[0153] The nitrogen-containing synergist may also be ammonium hydrogenophosphate, ammonium dihydrogenophosphate, or ammonium polyphosphate.

[0154] Other known flame-retardant synergists may also be optionally included in the polyamide molding composition in accordance with the invention. Examples of such synergists include metal oxides such as silica, iron oxide, titanium oxide, aluminum oxide, magnesium oxide, etc.; metal hydroxides and hydroxides oxides such as aluminum hydroxide, boehmite, magnesium hydroxide; metal salts such as zinc borate, zinc carbonate, magnesium carbonate, barium carbonate, barium metaborate.

[0155] Non-limitative examples of FRs include antimony trioxide, antimony pentoxide, antimony-metal compound, zinc borate, alumina trihydrate, magnesium hydroxide, and basalt fibers.

[0156] Any FR disclosed herein, alone or in combination with a synergist, may be used in the invention.

[0157] Glass fibers (GF)

[0158] The glass fibers (GF) dispersed in the polyamide molding composition stem from the use of roving as a starting material (see below).

[0159] The glass fibers disclosed herein may be modified by a sizing agent.

[0160] The glass of the glass fibers can consist of all sorts of glass, such as e.g. A-, C-, D-, E-, M-, S- , R-glass or any mixtures thereof. The glass of the glass fibers is preferably E-glass.

[0161] The glass of the glass fibers typically comprises silica (SiCh) with a proportion of at least 50.0 wt% and at least two oxides selected in the group consisting of AI2O3, B2O3, CaO, MgO, ZnO, BaO, U2O, Na2O, K2O, TiO2 and ZrO2. The glass of the glass fibers may comprise silica (SiCh) with a proportion of at least 50.0 wt% and AI2O3, B2O3, CaO, MgO, Na2O and K2O. The glass of the glass fibers may for instance be the following: between 50 and 60 wt% SiO2, between 10 and 20 wt% AI2O3, between 18 and 25 wt% CaO+MgO, between 5 and 15 wt% B2O3 and less than 2.5 wt% Na2O+K2O.

[0162] Additive(s) (Add)

[0163] The polyamide molding composition of the present invention may comprise at least one additive (Add), which is different from the flame retardant (FR) and from the GFs.

[0164] The additive (Add) is typically selected from the group consisting of impact modifiers, tougheners, plasticizers, colorants, pigments, antistatic agents, dyes, lubricants {e.g. calcium stearate, magnesium stearate or sodium montanate), thermal stabilizers, light stabilizers, antioxidants, nucleating agents, polymer processing aids, anti-blocking agents, slip agents, antifogging agents, chemical blowing agents, nucleating agents and any combination thereof.

[0165] In a preferred embodiment of the present invention, the additive (Add) is selected from the group consisting of impact modifiers, tougheners, plasticizers, colorants, pigments, antistatic agents, dyes, lubricants, antioxidants and any combination thereof.

[0166] In another preferred embodiment of the present invention, the additive (Add) is selected from the group consisting of plasticizers, colorants, pigments, antistatic agents, dyes, lubricants, antioxidants and any combination thereof.

[0167] Additional filler(s)

[0168] The polyamide molding composition may further comprise at least one additional filler which is different from the glass fibers (GFs), notably selected from the group consisting of mineral fillers {e.g. talc, mica, kaolin, calcium carbonate, calcium silicate, magnesium carbonate) and glass balls {e.g. hollow glass microspheres).

[0169] In one embodiment, the additional filler is selected from the group consisting of calcium carbonate, magnesium carbonate, graphite, carbon black, carbon fiber, carbon nanofiber, graphene, graphene oxide, fullerene, talc, wollastonite, mica, alumina, silica, titanium dioxide, kaolin, silicon carbide, zirconium tungstate, and boron nitride.

[0170] Preparation of the polyamide molding composition of the invention

[0171] The polyamide molding composition of the invention is obtained by the method comprising the following steps:- step a): introducing into an extruder, pellets (p) prepared from the GFs in the form of a roving impregnated by a composition (c) comprising all the components of the polyamide molding composition except glass fibers;- step b): molding the composition obtained after step a).

[0172] Composition (c) used in step a) comprises all the components of the polyamide molding composition (that is polyamide(s) (PA), flame-retardant(s) (FR), the optional additive(s) (Add) (if present in the polyamide molding composition) and the optional additional filler(s) (if present in the polyamide molding composition)) except the glass fibers (GF).

[0173] The proportions of the components of composition (c) are typically the following:- polyamide(s) (PA): between 50.0 and 80.0 wt%;- FR(s): between 20.0 and 50.0 wt%;- additive(s) (Add) and additional filler(s): between 0 and 20.0 wt%;these proportions being relative to the total weight of composition (c).

[0174] In step a), the pellets (p) are introduced into an extruder, notably in a single screw extruder. The conditions used in the extruder should allow to avoid or minimize the attrition of the GFs so as to obtain a distribution of the size of GFs with a high Lav and Lp. This can be accomplished with a screw that allows for a longer residence time in the feeding zone and for an extension of the transition zone. Screw 2 disclosed in the Experimental Section allows for this and may be used for the preparation of the polyamide molding composition of the invention.

[0175] The technique used in step b) for molding the composition obtained after step a) is typically selected in the group of extrusion molding, injection molding, blow molding, rotomolding, overmolding, compression molding and drawing extrusion molding. Step b) may be performed according to any one of the listed techniques. Extrusion molding and injection molding are convenient methods that allows the preparation of the polyamide molding composition of the invention. The technique used in step b) is conveniently injection molding.

[0176] The polyamide molding composition, notably at the end of step b), is typically in the form of pellets or in the form of a shaped article.

[0177] The conditions provided in the examples of the Experimental Section for the preparation of the polyamide molding composition can be followed (see §2) Injection molding).

[0178] About pellets (p)

[0179] Pellets (p) are prepared from impregnating a roving comprising a plurality of filaments of GF with a composition (c) comprising all the components of the polyamide molding composition except the glass fibers (GF).

[0180] The glass fibers used as starting material are in the form of roving and comprise end-less glass fibers, i.e. continuous glass fibers. It is noted that the length of the glass fibers is reduced in the method of preparation of pellets (p) and in the method of preparation so disclosed.

[0181] The details and embodiments mentioned in § [Glass fibers (GF)] above of course apply also to the glass of the glass fibers of the roving used to prepare pellet (p).

[0182] The pellets (p) are typically prepared by a method which comprises the steps of:- putting into contact the composition (c) in the molten form onto a roving comprising a plurality of filaments of GF;- passing the composite so obtained through an impregnation die;- after the die, the composite is cooled down and cut into the pellets (p).

[0183] An example of glass fibers in the form of a roving that can be conveniently used for the preparation of the polyamide molding composition of the invention is the Tufrov® 4510 roving from Nippon Electric Glass (see https: / / www.neg.co.jp / en / assets / file / product / fiber / e-roving / e- rovingJist / TufRov 4510 LFT roving 210907.pdf). These E-glass glass fibers generally exhibit a fiberdiameter d between 12 and 17 pm and a roving tex above 1000 g / km. Tufrov® 4510 ensures excellent spreadability of the roving filaments in thermoplastic pultrusion allowing complete resin impregnation.

[0184] An example of impregnation die that can be used is disclosed in EP 0320653, US 2013 / 0145986 A1 or in US 5,277,566.

[0185] The viscosity of the molten composition (c) should be low enough to allow a good spreading and impregnation of the composition (c) around the fibers, notably for thoroughly "wetting" and impregnating the fibers. To this effect, the temperature of the molten composition (c) needs to be high enough to decrease its viscosity.

[0186] The temperature of the molten composition (c) is typically much higher than the Tg of the polyamide(s) (PA) and if a semi-crystalline PA is present, at least Tm+40°C, preferably at least Tm+50°C, where designates the melting temperature of said semi-crystalline polyamide (PA). In the case of a combination of polyamide(s) (PA), the melting temperature to be taken into account is the highest Tg and highest Tm. Tm is generally between 350°C and 400°C.

[0187] The speed of the roving during the impregnation is typically between 1 .0 and 20.0 m / min, more particularly between 5.0 and 15.0 m / min.

[0188] The length of pellets (p) is typically between 4.0 and 15.0 mm, more preferably between 5.0 and 12.0 mm. The higher the length, the higher Lav and LPin the polyamide molding composition.

[0189] The invention also relates to a method of preparation of pellets (p) comprising the following steps:- putting into contact a composition (c) in the molten form onto a strand made up of a plurality of filaments of GF;- passing the composite so obtained through an impregnation die;- after the die, the composite is cooled down and cut into pellets (p); wherein composition (c) comprises polyamide (PA1) or polyamide (PA2) or polyamide (PA3); at least one FR as disclosed herein; optionally at least one additive (Add) as disclosed herein; optionally an additional filler (different from GFs) as disclosed herein.

[0190] The proportions of the components of composition (c) are notably the following:- polyamide (PA1) or (PA2) or (PA3): between 50.0 and 80.0 wt%;- FR(s): between 20.0 and 50.0 wt%;- additive(s) (Add) and additional filler(s): between 0 and 20.0 wt%; these proportions being relative to the total weight of composition (c).

[0191] Polyamide (PA1) may more particularly be a polyamide selected in the group consisting of 6T / 10T / BACT; 6T / 10T / 6.CHDA / 10.CHDA; 6T / 9T / 6.CHDA / 9.CHDA and combination thereof.

[0192] The conditions provided in the Experimental Section for the impregnation can be followed (see §1) Compounding).

[0193] Use of the polyamide molding composition

[0194] According to an embodiment, the polyamide molding composition of the invention, notably at the end of step b), is in the form of a shaped article. The polyamide molding composition exhibits resistance to thermal runaway.

[0195] The polyamide molding composition can therefore be used for the preparation of or as a thermal insulation barrier, notably in a rechargeable electrical energy storage system (REESS).

[0196] The polyamide molding composition can therefore be used for the preparation of or as a flame barrier during a thermal runaway event of a battery cell of a REESS.

[0197] A REESS typically comprises at least one battery cell and / or module.

[0198] The shaped article may be an enclosure of a REESS or the housing of a REESS, a wall {e.g. internal or external wall) of a REESS or the cover of a REESS. An example of enclosure is disclosed on Fig. 8 of US 2024 / 195007 or in US 2010 / 0273034 A1. An example of housing is disclosed in WO 2013 / 098121. Examples of articles are disclosed in EP 3460870.

[0199] The invention also relates to REESS comprising at least one thermal insulation barrier made of or comprising the polyamide molding composition of the invention. The thermal insulation barrier may be an enclosure of the REESS or the housing of the REESS, a wall {e.g. internal or external wall) of the REESS or the cover of the REESS.

[0200] The polyamide molding composition of the invention can be used for the preparation of at least one part of a battery enclosure, this part being notably selected in the group consisting of the housing, an internal wall or the cover of the battery enclosure.

[0201] The invention also relates to a REESS comprising at least one battery cell and a polyamide molding composition in the form of a shaped article wherein the shaped article provides a flame barrier during a thermal runaway of a battery cell of the REESS.[EXPERIMENTAL SECTION]

[0202] Raw MaterialsPolyamide (PA): Amodel® PPA Bios commercially available from Solvay Specialty Polymers USA, LLC. It is a 6T / 10T / 1 ,3-BACT copolyamide ; Tm is around 315°C, Tg is around 130°C and Hm is above 30 J / g;GF (I): TufRov™ 4510, E-glass fibers having fiber diameter of 12 pm, commercially available from Nippon Electric Glass;GF (II): ChopVantage® HP3610, E-glass fibers having nominal chop length of 3.2 mm and nominal fiber diameter of 10 pm, commercially available from Nippon Electric Glass;Flame retardant (FR): Exolit® OP1230 commercially available from Clariant GmbH.

[0203] Thermal properties of polyamide (PA): Tg, Tm and Hm are measured by Differential Scanning Calorimetry (“DSC”) according to ASTM D3418 using a heating and cooling rate of 20°C / min.

[0204] The wt% of each component of the polyamide molding composition are indicated in Table below.

[0205] The polyamide molding compositions were prepared by injection molding pellets obtained after compounding step which is disclosed below.

[0206] 1) Compounding

[0207] Conditions A for preparation of pellets (p): the PA was first tumble blended for 30 minutes in a 50-gallon drum to create a premix of the resin with additives (ADK Pep-36 and ADK AO-80 as antioxidants, commercially available from Adeka) to produce premixes. The premixes were then metered to the feed throat of a 25 mm Berstorff co-rotating intermeshing twin-screw extruder having 8 barrel sections. The resin mix was metered at a rate of 78.00 Ib / hr using a gravimetric feeder. The FRs were fed into barrel 7, using a gravimetric feeder, at a rate of 22.5 Ib / hr. Vacuum venting was provided at barrel section 8 achieving a vacuum level of 25 in Hg to remove moisture and any other volatile residues from the compounds. The extrudates were kept hot at 370°C before adding the same to GFs (I) (roving). The polymer coating was first cooled and cut into pellets (p) of 9 mm length.

[0208] These conditions used for the preparation of the pellets (p) are referenced as conditions A.

[0209] Conditions B for preparation of pellets: the PA was first tumble blended for 30 minutes in a 50-gallon drum to create a premix of the resins with additives (ADK Pep-36 and ADK AO-80 as antioxidants, commercially available from Adeka) to produce premixes. The premixes were then metered to the feed throat of a 25 mm Berstorff co-rotating intermeshing twin-screw extruder having 8 barrel sections. The resin mix was metered at a rate of 13.00 Ib / hr using a gravimetric feeder. The GFs (II) were fed at barrel section 6, also using a gravimetric feeder at a rate of 8.25 Ib / hr. The FRs were fed into barrel 7, using a gravimetric feeder at a rate of 3.75 Ib / hr. The total compounding throughput was at a rate of 25 Ib / hr. The barrel section temperature was set during compounding to 216°C (barrel 2), 306°C (barrel 3), 340°C (barrels 3-4), and 300° C (barrels 5-9; adaptor; die). The temperature of the melt was monitored during the compounding using a handheld temperature probe and was determined to be in the range of from 330°C to 350°C. Vacuum venting was provided at barrel 8 achieving a vacuum level of 25 in Hg to remove moisture and any other volatile residues from the compound. The extrudates were stranded from the die, cooled in a water bath and then cut into cylindrical pellets having approximately 3.0 mm in length and 2.7 mm in diameter.

[0210] 2) Injection Molding (IM)

[0211] The pellets obtained from the conditions 1) disclosed above (under conditions A or B) were first dried at 82°C in a desiccated convection air oven for at least 8 hours (overnight) in preparation for the injection molding. Injection molding was then performed to produce articles for testing and performancemeasurement, by using an injection molding machine SE180EV-A-SL equipped with a hopper dryer (this machine is commercially available from Sumitomo and is equipped with a screw diameter 50 mm) to maintain the dried pellets moisture content. The cycle time varied from 36.0 to 47.0 seconds and the fill peak pressure was adjusted between 7000 and 9000 psi. The temperature of the composition during injection was about 271 °C. The dimensions of the plaques prepared were 152mm X 152mm X 2mm and 101mm X 101mm X 2mm. Further ISO tensile bars were also injection molded according to ISO180.

[0212] Two types of screws were used in the extruder used for IM:- screw 1 : this is the default screw present with the injection molding machine SE180EV-A-SL as commercialized. Conditions of extrusion: flat temperature profile of 320 °C were used across barrel zones during the molding; mold temperature was kept at 155 °C;- screw 2: the design of the default screw was modified. The key idea behind this modification is to accelerate the melting of the pellets in the feeding zone to avoid glass fiber attrition occurring in the transition zone without sufficient melting in the feeding zone. Design of the screw 2: 1) increased flight depth in the feeding zone to allow for longer residence time: from 3.8 for screw 1 to 6.8 mm for screw 2; 2) extension of the transition zone. The default screw has no transition zone due to the compression ratio of 1 :1 , while the new screw 2 has a section ratio of 5:9.5:2.5 (feed transition: meter) to minimize any abrupt compression which could potentially shatter pellets due to their viscoelastic properties. Conditions: flat temperature profile of 320 °C were used across barrel zones during the molding; mold temperature was kept at 155 °C.

[0213] The polyamide molding composition obtained is in the form of a shaped article (plaque of rectangular shape).

[0214] Method for measuring the parameters of the distributions of the sizes of the GFs

[0215] Ash method used: the method used is performed following ISO 22314:2006(E). The polyamide molding composition was cut into pieces, e.g. 10mm X 10mm X 2mm size, and the pieces were stored in an oven at 525°C for 4.5 hours. After decomposition, the GFs were isolated and dispersed into a plastic petri dish. Duration may be increased if decomposition is not completed.

[0216] Image analysis: the isolated GFs were imaged using an optical microscope and the lengths of a statistically significant number of GFs were measured on the images.

[0217] The distribution was reported in the form of a histogram of fiber lengths. From the histogram, all the values of the distributions that are used herein are determined (e.g. Lav, Lp, proportions of the lengths of the GFs).Table 1

[0218] The polyamide molding compositions of examples E1-E2 according to the invention exhibit resistance to thermal stress. All examples exhibit a time-to-failure tp of at least 90.0 s under the conditions provided in § "Time of failure (tp)".

[0219] The polyamide molding compositions of examples E1-E2 according to the invention also exhibit an improved impact strength and an improved tensile strength at break.

Claims

Claims1. Polyamide molding composition comprising, consisting essentially of or consisting of: between 15.0 wt% and 70.0 wt% of at least one polyamide (PA) selected in the group consisting of aliphatic polyamides, polyphthalamides (PPA) and combinations thereof, polyamide (PA) preferably exhibiting:■ a melting temperature (Tm) of at least 250.0°C and a heat of fusion (Hm) of at least 30.0 J / g; and / or■ a glass transition temperature (Tg) of at least 60.0°C;■ Tm, Hmand Tgbeing measured by Differential scanning calorimetry (DSC) according to ASTM D3418, notably using a heating and cooling rate of 20°C / min; between 20.0 wt% and 75.0 wt% of glass fibers (GFs) dispersed in the polyamide molding composition; between 1.0 wt% and 30.0 wt% of at least one flame retardant (FR); and optionally at least one additive (Add) other than the flame retardant (FR) and other than the glass fiber (GFs), notably selected from the group consisting of impact modifiers, tougheners, plasticizers, colorants, pigments, antistatic agents, dyes, lubricants, thermal stabilizers, light stabilizers, antioxidants, nucleating agents, polymer processing aids, antiblocking agents, slip agents, antifogging agents, chemical blowing agents, nucleating agents and any combination thereof; these proportions in wt% being provided relative to the total weight of the polyamide molding composition; wherein the distribution of the lengths of the GFs in the polyamide molding composition is characterized by set of parameters (S1) or (S2) or by set of parameters (S1) and (S2), (S1) and (S2) being obtained respectively from a number-weighted distribution and a volume-weighted distribution:both the number-weighed and the volume-weighted distributions being obtained after the separation of the dispersed GFs from the polyamide molding composition.

2. Polyamide molding composition according to claim 1 , wherein Lav is between 800 pm and 3000 pm, preferably between 900 pm and 1500 pm.

3. Polyamide molding composition according to claim 1 or 2, wherein for the number-weighted distribution, (iia) the proportion of the GFs having a length higher than 1500 pm is at least 45.0% and / or (iib) the proportion of the GFs having a length higher than 2500 pm of at least 35.0%.

4. Polyamide molding composition according to any one of the preceding claims, wherein for the number- weighted distribution, (iia) the proportion of the GFs having a length higher than 1500 pm is at least 50.0%, preferably at least 55.0%, preferably at least 60.0%.

5. Polyamide molding composition according to any one of the preceding claims, wherein for the number- weighted distribution, (iib) the proportion of the GFs having a length higher than 2500 pm is at least 40.0%.

6. Polyamide molding composition according to any one of the preceding claims, wherein for the number- weighted distribution, (iia) the proportion of the GFs having a length higher than 1500 pm is at most 70.0% and / or (iib) the proportion of the GFs having a length higher than 2500 pm of at most 50.0%.

7. Polyamide molding composition according to any one of the preceding claims, wherein for the number- weighted distribution, (iic) the proportion of the GFs having a length higher than 400 pm of at least 80.0% and / or (iid) the proportion of the GFs having a length higher than 500 pm of at least 75.0%.

8. Polyamide molding composition according to any one of the preceding claims, wherein from the number-weighted distribution, at least 90.0% of the GFs have a length lower than or equal to 9000 pm, preferably lower than or equal to 2500 pm.

9. Polyamide molding composition according to any one of the preceding claims, wherein Lp is between 2000 pm and 3500 pm, preferably between 2000 and 3000 pm, preferably between 2000 and 2700 pm.

10. Polyamide molding composition according to any one of the preceding claims, wherein from the volume-weighted distribution, (iia) the proportion of the GFs having a length higher than 1500 pm is at least 60.0%.

11. Polyamide molding composition according to any one of the preceding claims, wherein from the volume-weighted distribution, (iib) the proportion of the GFs having a length higher than 2500 pm is at least 50.0%.

12. Polyamide molding composition according to any one of the preceding claims, wherein from the volume-weighted distribution, (iia) the proportion of the GFs having a length higher than 1500 pm is at least 80.0% and / or (iib) the proportion of the GFs having a length higher than 2500 pm is at least 65.0%.

13. Polyamide molding composition according to any one of the preceding claims, wherein from the volume-weighted distribution, (iia) the proportion of the GFs having a length higher than 1500 pm is at least 85.0% and / or (iib) the proportion of the GFs having a length higher than 2500 pm is at least 70.0%.

14. Polyamide molding composition according to any one of the preceding claims, wherein from the volume-weighted distribution, (iia) the proportion of the GFs having a length higher than 1500 pm is at most 95.0% and / or (iib) the proportion of the GFs having a length higher than 2500 pm is at most 85.0%.

15. Polyamide molding composition according to any one of the preceding claims, wherein from the volume-weighted distribution, (iic) the proportion of the GFs having a length higher than 400 pm is at least 99.0% and / or (iid) the proportion of the GFs having a length higher than 500 pm is at least 98.0%.

16. Polyamide molding composition according to any one of the preceding claims, wherein the proportion of the polyamide(s) (PA) in the polyamide molding composition is:- between 20.0 wt% and 65.0 wt%; or- between 30.0 wt% and 65.0 wt%; or- between 35.0 wt% and 65.0 wt%; or- between 35.0 wt% and 60.0 wt%; or- preferably between 35.0 wt% and 55.0 wt%.

17. Polyamide molding composition according to any one of the preceding claims, wherein the proportion of the GFs dispersed in the polyamide molding composition is:- between 20.0 and 60.0 wt%; or- between 30.0 and 60.0 wt%; or- between 30.0 and 55.0 wt%; or- between 30.0 and 50.0 wt%.

18. Polyamide molding composition according to any one of the preceding claims, wherein the proportion of the FR(s) in the polyamide molding composition is between 5.0 and 20.0 wt% or between 8.0 and 20.0 wt% or between 10.0 and 20.0 wt%.

19. Polyamide molding composition according to any one of the preceding claims, wherein the proportion of additive(s) (Add) in the polyamide molding composition is between 0 and 15.0 wt% or between 0 and 10.0 wt%.

20. Polyamide molding composition according to any one of the preceding claims, wherein the polymeric component of the polyamide molding composition consists of the one or more polyamides (PA).

21. Polyamide molding composition according to any one of the preceding claims, wherein the glass fibers (GF) have a diameter d from 5.0 pm to 20.0 pm.

22. Polyamide molding composition according to any one of the preceding claims, exhibiting a time-to- failure (tp) of at least 90.0 s, preferably at least 100.0 s, tp being measured according to the Torch-and- Grit” (TaG) test disclosed in UL 2596, issue N°2 released on 8 September 2023, the sample having notably a thickness of 3 mm.

23. Polyamide molding composition according to any one of the preceding claims, exhibiting a time-to- failure (tp 73) of at least 100 s, preferably at least 120 s, tp T3 being the time until the back surface of a plaque (152mm X 152mm X 2mm) of the polyamide molding composition is damaged under test GMW- 18435 (type 1 ; with no carbon steel plate backing assembly).

24. Polyamide molding composition according to any one of the preceding claims, exhibiting an impact strength (notched Izod; room temperature; measured according to ISO 180; specimen size: type 1A bar) of at least 28.0 kJ / m2, preferably at least 30.0 kJ / m2.

25. Polyamide molding composition according to any one of the preceding claims, exhibiting a tensile strength at break (speed: 5 mm / min; measured according to ISO 527; specimen size: type 1 A bar) of at least 200 MPa.

26. Polyamide molding composition according to any one of the preceding claims, wherein polyamide (PA) exhibits a Tg of at least 90.0°C, preferably at least 100.0°C, preferably at least 120.0°C, preferably at least 130.0°C.

27. Polyamide molding composition according to any one of the preceding claims, wherein polyamide (PA) exhibits: a melting temperature (Tm) of at least 295.0°C, preferably at least 300.0°C, preferably at least 310.0°C; and / or a heat of fusion (Hm) of at least 35.0 J / g, preferably at least 40.0 J / g, preferably at least 50.0 J / g; or exhibits: a melting temperature (Tm) of at least 300.0°C, preferably at least 310.0°C; and / or a heat of fusion (Hm) of at least 40.0 J / g.

28. Polyamide molding composition according to any one of the preceding claims, wherein polyamide (PA) comprises at least 95.0 mol% of recurring units (RPA) resulting from the condensation of: a dicarboxylic acid component (A) comprising: (i) at least one phthalic acid selected from the group consisting of isophthalic acid (I), terephthalic acid (T) and combination of I and T, and (ii) optionally at least one dicarboxylic acid of formula (I) HOOC-R1-COOH, where R1 is selected from the group consisting of a C2-C18 alkylene group, a CB-C-IS cycloalkylene group and combination thereof; and a diamine component (B) comprising at least one diamine of formula (II) H2N-R2-NH2, where R2 is selected from the group of a C4-C18 alkylene, a divalent radical derived from Z? / s(anninomethyl) cyclohexane selected from the group consisting of 1 ,3-BAC, 1 ,4-BAC and combination thereof.

29. Polyamide molding composition according to claim 28, wherein the dicarboxylic acid component (A) consists essentially of or consists of: (i) at least one phthalic acid selected from the group consisting of isophthalic acid (I), terephthalic acid (T) and combination of I and T and (ii) optionally at least one dicarboxylic acid (DI) of formula (I) where Ri is selected from the group consisting of a C2-C18 linear or branch alkylene group, a CB-C-IS cycloalkylene group and combination thereof where the expression "consist essentially" means in the context of the dicarboxylic acid component (A) that the dicarboxylic acid component (A) consists of:(j) the phthalic acid(s) and the dicarboxylic acid(s) (DI) of formula (I); and(jj) up to 1.5 mol%, preferably up to 1.0 mol%, preferably up to 0.5 mol%, of at least one dicarboxylic acid not belonging to the dicarboxylic acids listed in (j).

30. Polyamide molding composition according to claim 28 or 29, wherein the diamine component (B) consists essentially of or consists of at least one diamine of formula (II) H2N-R2-NH2 where R2 is selected from the group of a C4-C18 alkylene, a divalent radical derived from £> / s(ami nomethyl) cyclohexane (BAG) selected from the group consisting of 1 ,3-BAC, 1 ,4-BAC and combination thereof, where the expression "consist essentially" means in the context of the diamine component (B) that the diamine component (B) consists of:(j) the diamine(s) of formula (II) H2N-R2-NH2; and(jj) up to 1 .5 mol%, preferably up to 1 .0 mol%, preferably up to 0.5 mol%, of at least one diamine not belonging to the diamines listed in (j).

31. Polyamide molding composition according to any one of claims 28-30, wherein R1 is selected from the group consisting of a C4-C8 alkylene group, a cycloalkylene group and combination thereof.

32. Polyamide molding composition according to any one of claims 28-31 , wherein R2 is selected from the group consisting of a C4-C8 alkylene group, a divalent radical derived from £> / s(ami nomethyl) cyclohexane and combination thereof.

33. Polyamide molding composition according to any one of preceding claims, wherein polyamide (PA) comprises at least 95.0 mol% of recurring units (RPA) formed from the condensation of a dicarboxylic acid component (A) and a diamine component (B), where the dicarboxylic acid component (A) consists essentially of or consists of:■ between 90.0 mol% and 100 mol% of terephthalic acid,■ between 0 mol% and 10.0 mol% of a dicarboxylic acid (DI) selected from the group consisting of CB-CIS aliphatic dicarboxylic acid of formula HOOC-(CH2)n-COOH where n is an integer between 4 and 16, isophthalic acid and combination thereof; and■ between 0 mol% and 10.0 mol% of 1 ,4-cyclohexanedicarboxylic acid,■ where mol% is relative to the total number of moles of dicarboxylic acids in the dicarboxylic acid component (A) and where the expression "consist essentially" means in the context of the dicarboxylic acid component (A) that the dicarboxylic acid component (A) consists of:(j) terephthalic acid, the dicarboxylic acid(s) (DI), the 1 ,4- cyclohexanedicarboxylic acid, with the proportions indicated; and(jj) up to 1.5 mol%, preferably up to 1.0 mol%, preferably up to 0.5 mol%, of at least one dicarboxylic acid not belonging to the dicarboxylic acids listed in (j); the diamine component (B) consists essentially of or consists of:■ between 55.0 mol% and 75.0 mol% of one or more C4-C8 aliphatic diamines;■ between 25.0 mol% and 45.0 mol% of an aliphatic diamine selected from the group consisting of 1 ,9-nonanediamine, 1 ,10-decanediamine and combination thereof;■ between 0 mol% and 10.0 mol% of a Z? / s(aminomethyl) cyclohexane selected from the group consisting of 1 ,3-BAC, 1 ,4-BAC and combination thereof;■ where mol% is relative to the total number of moles of diamines in the diamine component (B) and where the expression "consist essentially" means in the context of the diamine component (B) that the diamine component (B) consists of:(j) the C4-C8 aliphatic diamine(s), the aliphatic diamine selected from the group consisting of 1 ,9-nonanediamine, 1 ,10-decanediamine and combination thereof, the Z? / s(aminomethyl) cyclohexane(s), with the proportions indicated; and(jj) up to 1.5 mol%, preferably up to 1.0 mol%, preferably up to 0.5 mol%, of at least one diamine not belonging to the diamines listed in (j); wherein the Z? / s(anninomethyl) cyclohexane or the 1 ,4-cyclohexanedicarboxylic acid or both exhibit a proportion of greater than 0.5 mol% respectively in the dicarboxylic acid component (A) and in the diamine component (B).

34. Polyamide molding composition according to any one of preceding claims, wherein polyamide (PA) comprises at least 95.0 mol% of recurring units (RPA) formed from the condensation of a dicarboxylic acid component (A) and a diamine component (B), where the dicarboxylic acid component (A) consist essentially of or consists of terephtalic acid, where the expression "consist essentially" means in the context of the dicarboxylic acid component (A) that the dicarboxylic acid component (A) consists of (j) terephthalic acid; and (jj) up to 1 .5 mol%, preferably up to 1.0 mol%, preferably up to 0.5 mol%, of at least one dicarboxylic acid distinct from terephthalic acid; the diamine component (B) consists essentially of or consists of:■ between 55.0 mol% and 75.0 mol% of one or more C4-C8 aliphatic diamines;■ between 25.0 mol% and 45.0 mol% of an aliphatic diamine selected from the group consisting of 1 ,9-nonanediamine, 1 ,10-decanediamine and combination thereof;■ between 0.5 mol% and 10.0 mol% of a Z? / s(aminomethyl) cyclohexane selected from the group consisting of 1 ,3-BAC, 1 ,4-BAC and combination thereof;■ where mol% is relative to the total number of moles of diamines in the diamine component (B) and where the expression "consist essentially" means in the context of the diamine component (B) that the diamine component (B) consists of:(j) the C4-C8 aliphatic diamine(s), the aliphatic diamine selected from the group consisting of 1 ,9-nonanediamine, 1 ,10-decanediamine and combination thereof, the Z? / s(aminomethyl) cyclohexane(s), with the proportions indicated; and(jj) up to 1.5 mol%, preferably up to 1.0 mol%, preferably up to 0.5 mol%, of at least one diamine not belonging to the diamines listed in (j).

35. Polyamide molding composition according to any one of preceding claims, wherein polyamide (PA) comprises at least 95.0 mol% of recurring units (RPA) formed from the condensation of a dicarboxylic acid component (A) and a diamine component (B), where: the dicarboxylic acid component (A) consists essentially of or consists of:■ between 90.0 mol% and 99.0 mol% of terephthalic acid,■ between 1.0 mol% and 10.0 mol% of 1 ,4-cyclohexanedicarboxylic acid,■ where mol% is relative to the total number of moles of dicarboxylic acids in the dicarboxylic acid component (A) and where the expression "consist essentially" means in the context of the dicarboxylic acid component (A) that the dicarboxylic acid component (A) consists of:(j) terephthalic acid and the 1 ,4-cyclohexanedicarboxylic acid, with the proportions indicated; and(jj) up to 1.5 mol%, preferably up to 1.0 mol%, preferably up to 0.5 mol%, of at least one dicarboxylic acid not belonging to the dicarboxylic acids listed in (j); where the diamine component (B) consist essentially of or consists of:■ between 50.0 mol% and 90.0 mol% of one or more C4-C8 aliphatic diamines;■ between 10.0 mol% and 50.0 mol% of a Z? / s(aminomethyl) cyclohexane selected from the group consisting of 1 ,3-BAC, 1 ,4-BAC and combination thereof;■ where mol% is relative to the total number of moles of diamines in the diamine component (B) and where the expression "consist essentially" means in the context of the diamine component (B) that the diamine component (B) consists of:(j) the C4-C8 aliphatic diamine(s) and the Z? / s(aminomethyl) cyclohexane(s), with the proportions indicated; and(jj) up to 1.5 mol%, preferably up to 1.0 mol%, preferably up to 0.5 mol%, of at least one diamine not belonging to the diamines listed in (j).

36. Polyamide molding composition according to any one of claims 32-35, wherein the C4-C8 aliphatic diamine present in the diamine component (B) consists of 1 ,6-diaminohexane.

37. Polyamide molding composition according to any one of claims 28-36, wherein the proportion of recurring units (RPA) is at least 99.0 mol% or the recurring units of polyamide (PA) consist of recurring units (RPA).

38. Polyamide molding composition according to any one of the preceding claims, wherein polyamide (PA) is selected from the group consisting of:PA 66;- 9T;10T;6T / 6I / 66;- 6T / 66;6T / 6I;6T / 10T;6T / 10T / BACT, where BAG is 1 ,3-BAC and / or 1 ,4-BAC, preferably 1 ,3-BAC;6T / BACT / 66 / BAC6, where BAG is 1 ,3-BAC and / or 1 ,4-BAC, preferably 1 ,3-BAC;6T / 10T / 6.CHDA / 10.CHDA; and6T / 9T / 6.CHDA / 9.CHDA where CHDA is 1 ,4-cyclohexanedicarboxylic acid; a combination thereof.

39. Polyamide molding composition according to any one of the preceding claims, wherein the FR is or comprises at least one organophosphorous compound selected from the group consisting of phosphinic salts (phosphinate) of formula (a), diphosphinic salts (diphosphinate) of formula (b) and combination thereof:(b),wherein R7and R8, identical ordifferent, are C-I-CB alkyl, linear or branched, or aryl; R9is C1-C10 alkylene, linear or branched, CB-CIO arylene, alkylarylene or arylalkylene; M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ge, Bi, Sr, Mn, Li, Na, K or a protonated nitrogen base; m is 1 to 4; n is 1 to 4; and x is 1 to 4.

40. Polyamide molding composition according to any one of the preceding claims, wherein the FR is or comprises an aluminum phosphinate, notably aluminium ethylmethylphosphinate and / or aluminium diethylphosphinate or calcium phosphinate or zinc phosphinate.

41. Polyamide molding composition according to any one of the preceding claims, obtained by the method comprising the following steps:- step a): introducing into an extruder pellets (p) prepared from the GFs in the form of a roving impregnated by a composition (c) comprising all the components of the polyamide molding composition except the glass fibers;- step b): molding the composition obtained after step a), step (b) being notably selected in the group of extrusion molding, injection molding, blow molding, rotomolding, overmolding, compression molding and drawing extrusion molding.

42. Polyamide molding composition according to any one of the preceding claims in the form of pellets or in the form of a shaped article.

43. Polyamide molding composition according to any one of the preceding claims, wherein the proportion of components of the polyamide molding composition are the following: between 20.0 wt% and 65.0 wt% of polyamide(s) (PA): between 20.0 wt% and 60.0 wt% of the glass fibers (GFs); between 1.0 wt% and 30.0 wt%, preferably between 5.0 wt% and 20.0 wt%, more preferably between 8.0 and 20.0 wt%, of flame retardant(s) (FR); or the following: between 35.0 wt% and 65.0 wt% of polyamide(s) (PA): between 20.0 wt% and 60.0 wt% of the glass fibers (GFs); between 1.0 wt% and 30.0 wt%, preferably between 5.0 wt% and 20.0 wt%, more preferably between 8.0 and 20.0 wt%, of flame retardant(s) (FR);44. Polyamide molding composition according to any one of the preceding claims, wherein the proportion of components of the polyamide molding composition are the following: between 35.0 wt% and 55.0 wt% of polyamide(s) (PA); between 30.0 wt% and 50.0 wt% of the glass fibers (GFs); between 1.0 wt% and 30.0 wt%, preferably between 5.0 wt% and 20.0 wt%, more preferably between 8.0 and 20.0 wt%, of flame retardant(s) (FR).

45. Use of a polyamide molding composition as defined in any one of claims 1-44, for the preparation of a thermal insulation barrier in a rechargeable electrical energy storage system (REESS).

46. Use of a polyamide molding composition as defined in any one of claims 1-44, as thermal insulation barrier, notably in a rechargeable electrical energy storage system (REESS).

47. Use of a polyamide molding composition as defined in any one of claims 1-44, for the preparation of or as a flame barrier during a thermal runaway event of a battery cell of a REESS.

48. Rechargeable electrical energy storage system (REESS) comprising at least one thermal insulation barrier made of or comprising the polyamide molding composition as defined in any one of claims 1-44.

49. Rechargeable electrical energy storage system (REESS) comprising at least one battery cell and a polyamide molding composition as defined in any one of claims 1-44 which is in the form of a shaped article wherein the shaped article provides a flame barrier during a thermal runaway of a battery cell of the REESS.

50. Use of pellets (p) prepared from impregnating a roving comprising a plurality of filaments of GF with a composition (c) comprising: at least one polyamide (PA) selected in the group consisting of aliphatic polyamides, polyphthalamides (PPA) and combinations thereof, polyamide (PA) preferably exhibiting:■ a melting temperature (Tm) of at least 250.0°C and a heat of fusion (Hm) of at least 30.0 J / g; and / or■ a glass transition temperature (Tg) of at least 60.0°C;■ Tm, Hm and Tg being measured by Differential scanning calorimetry (DSC) according to ASTM D3418, notably using a heating and cooling rate of 20°C / min; at least one flame retardant (FR); and optionally at least one additive (Add) other than the flame retardant (FR) and other than the glass fibers (GF), notably selected from the group consisting of impact modifiers, tougheners, plasticizers, colorants, pigments, antistatic agents, dyes, lubricants, thermal stabilizers, light stabilizers, antioxidants, nucleating agents, polymer processing aids, antiblocking agents, slip agents, antifogging agents, chemical blowing agents, nucleating agents and any combination thereof; for the preparation of a polyamide molding composition as defined in any one of claims 1-44.

51. Use according to claim 50, wherein the polyamide (PA) is a PPA, notably polyamide (PA1), (PA2) or (PA3) as defined herein.

52. Use according to claims 50 or 51 , wherein polyamide (PA) is selected from the group consisting of:PA 66;6T / 6I / 66;- 6T / 66;6T / 6I; - 6T / 10T;6T / 10T / BACT, where BAG is 1 ,3-BAC and / or 1 ,4-BAC, preferably 1 ,3-BAC;6T / BACT / 66 / BAC6, where BAG is 1 ,3-BAC and / or 1 ,4-BAC, preferably 1 ,3-BAC;6T / 10T / 6.CHDA / 10.CHDA; and6T / 9T / 6.CHDA / 9.CHDA where CHDA is 1 ,4-cyclohexanedicarboxylic acid; - a combination thereof.

Images