Flame retardant thermoplastic composition

Abstract

The present invention relates to a thermoplastic composition comprising, based on the weight of the thermoplastic composition, (A) from 40 to 60 wt.% of polyester comprising or consisting of polybutylene terephthalate, (B) from 10 to 45 wt.% of glass fibers, (C) from 10 to 20 wt.% of a flame retardant composition comprising - antimony compound - organo-bromo flame retardant agent - melamine compound and - optionally anti-drip agent (D) from 0 to 20 wt.% of polycarbonate and (E) from 0 to 5.0 wt.% of further components wherein the total amounts of (A) to (E) is 100 wt.% with respect to the composition.

Description

FLAME RETARDANT THERMOPLASTIC COMPOSITIONThe present invention relates to a flame retardant thermoplastic composition and an article comprising such composition, such as components used in combination with batteries of electric vehicles.Electric vehicles (EV) play an increasingly important role in people’s traveling. The safety issues of EV battery are drawing more and more attention. Fire and explosion in EV by thermal runaway of power lithium-ion batteries have occurred from time to time, not only seriously endangering the lives and properties of drivers and passengers, but also greatly hindering the promotion and development of new energy vehicles. Flame retardancy are therefore essential in polymer compositions for use in components used in combination with batteries of electric vehicles..W02020064752A1 discloses a composition suitable for use in articles such as battery carriers and covers in electric cars. The composition is a glass fiber filled flame retardant polypropylene composition comprising (A) a propylene-based polymer, (B) a first flame retardant in the form of particles comprising ammonium polyphosphate and at least one specific type of phosphate and (C) a second flame retardant comprising an aromatic phosphate ester and (D) glass fibers.WO2 023067071 A1 discloses an article for covering battery components in an automotive prime-mover battery pack, the article comprising a top cover having an outer major surface and an inner major surface that is shaped to conform to the battery components, wherein the top cover is prepared by extrusion of a composition comprising a polyolefin and glass fibers to obtain a sheet and subsequent thermoforming of the sheet and wherein the article is configured to form an outer char coating when exposed to flame.WO2016174592A1 discloses a flame retardant composition comprising 20 to 80 weight percent of a polycarbonate; and 1 to 20 weight percent of a halogenated phenoxyphosphazene flame retardant, and optionally further 10 to 60 wt% of a polyester.CN 107418156B, CN106380796A and CN 107163518A disclose flame retardant PBT compositions with glass fibers, antimony oxide, bromine based flame retardant and melamine compounds. No application in battery housing is mentioned.Components used in combination with batteries of electric vehicles, such as battery housings, need to withstand a particularly high temperature. In some cases, they need to be intact, i.e. keep their surfaces without a hole, after being subjected to a temperature of 1000 °C for 5 minutes.It is an objective of the invention to provide a thermoplastic composition which has a high flame retardancy to withstand the severe conditions required for components used in combination with batteries of electric vehicles.Accordingly, the invention provides a thermoplastic composition comprising, based on the weight of the composition,(A) from 40 to 60 wt.% of polyester comprising or consisting of polybutylene terephthalate,(B) from 10 to 45 wt.% of glass fibers,(C) from 10 to 20 wt.% of a flame retardant composition comprising antimony compound organo-bromo flame retardant agent melamine compound and optionally anti-drip agent,(D) from 0 to 20 wt.% of polycarbonate and(E) from 0 to 5.0 wt.% of further components wherein the total amounts of (A) to (E) is 100 wt.% with respect to the composition.More specifically, the present invention provides a thermoplastic composition comprising, based on the weight of the composition,(A) from 40 to 60 wt.% of polyester comprising or consisting of polybutylene terephthalate,(B) from 10 to 45 wt.% of glass fibers,(C) from 10 to 20 wt.% of a flame retardant composition comprising antimony compoundorgano-bromo flame retardant agent melamine compound and optionally anti-drip agent,(D) from 0 to 20 wt.% of polycarbonate and(E) from 0 to 5.0 wt.% of further components wherein the total amounts of (A) to (E) is 100 wt.% with respect to the composition, wherein the thermoplastic composition is selected to pass a flame test, wherein the flame test involves- molding the thermoplastic composition into a test specimen having a thickness of 3 mm and a top main surface and a bottom main surface having dimensions of 150 mm x 150 mm,- placing the specimen horizontally,- exposing the bottom main surface to a tip of a flame of 1 ,000 °C for 5 minutes using a heat source of a mixture of butane, propane and air and- determining that the thermoplastic composition passed the flame test if no hole is visually detectable on the top main surface and that the thermoplastic composition failed the flame test if a hole is visually detectable on the top main surface.It was surprisingly found that the thermoplastic composition according to the invention has a very high flame retardancy at high temperature. According to the invention, the melamine compound was found to act as a synergist for the combination of the antimony compound and the organo-bromo flame retardant agent in a polyester composition. This is particularly surprising since the use of a melamine compound in a flame retardant composition is known to have detrimental effects to the results of flame resistance test such as LIL94 testing.The thermoplastic composition comprises a polyester.It was observed that the flame retardant composition according to the invention can impart a better flame retardancy to a polyester-based composition than to a polycarbonate-based composition.The amount of the polyester in the thermoplastic composition is 40 to 60 wt%, for example 45 to 55 wt%.Polyesters have repeating structural units of formulawherein each T is independently the same or different divalent C6-10 aromatic group derived from a dicarboxylic acid or a chemical equivalent thereof, and each D is independently a divalent C2-4 alkylene group derived from a dihydroxy compound or a chemical equivalent thereof. Copolyesters containing a combination of different T and / or D groups can be used. Chemical equivalents of diacids include the corresponding esters, alkyl esters, e.g., C1-3 dialkyl esters, diaryl esters, anhydrides, salts, acid chlorides, acid bromides, and the like. Chemical equivalents of dihydroxy compounds include the corresponding esters, such as C1-3 dialkyl esters, diaryl esters, and the like. The polyesters can be branched or linear.The polyester comprises or consists of poly(butylene terephthalate) ("PBT"), which is a type of polyalkylene terephthalates (“PAT”). The polyester may comprise different types of PAT in addition to PBT. In addition to PBT, the polyester may further comprise polyesters other than PAT, for example poly(alkylene naphthalate) ("PAN") and poly(cyclohexane-1 ,4- dimethylene cyclohexane-l,4-dicarboxylate) also known as poly(1 ,4- cyclohexanedimethanol 1 ,4-dicarboxylate) ("PCCD").Polyalkylene TerephthalatePolyalkylene terephthalates in the context of the invention are polyalkylene terephthalates which are derived from terephthalic acid (or its reactive derivatives) and alkanediols, for example based on ethylene glycol, propylene glycol or butanediol or copolymerized polyesters having polyalkylene terephthalate as a principal component included in a polyester.Examples of the polyalkylene terephthalates of the present invention include, but are not limited to, poly(ethylene terephthalate) ("PET"), poly( ethylene terephthalate-co- ethylene adipate ("PETA"), poly(butylene terephthalate) ("PBT"), polypropylene terephthalate) ("PPT"), polypyclohexylenedimethylene terephthalate) ("PCT"), poly(trimethylene terephthalate) ("PTT"), poly(1 ,4-cyclohexylene dimethylene terephthalate-co-isophthalate) ("PCTA"), glycol modified polycyclohexylenedimethylene terephthalate ("PCTG"), glycol-modified polyethylene terephthalate ("PETG"), or combinations of one or more of each type of the polyalkylene terephthalates.Preferably, the PBT has an intrinsic viscosity of 0.4 to 1.4 cm3 / g. As used herein, intrinsic viscosity is measured in a 60:40 mixture of phenol / tetrachloroethane mixture at 25°C according to ASTM D 2857-70 using a viscosimeter according to DIN 51562.The PBT may be a combination of PBT having different intrinsic viscosities. For example, the PBT may comprise or consist of a first PBT having an intrinsic viscosity of 0.8 to 1.4 cm3 / g and a second PBT having an intrinsic viscosity of 0.4 to 0.8 cm3 / g.Preferably, the amount of the PBT with respect to the total polyester in the thermoplastic composition is at least 40 wt%, for example 40 to 50 wt% or 50 to 100 wt% or 60 to 99 wt%. In some embodiments, the amount of the PBT with respect to the total polyester in the thermoplastic composition is at least 90 wt%, at least 95 wt%, at least 98 wt%, at least 99 wt%, at least 99.5 wt%, at least 99.9 wt% or 100 wt%.In some embodiments, the polyester further comprises PET.Preferably, the PET has an intrinsic viscosity of 0.4 to 1 .4 cm3 / g.PET generally has a higher melting point than PBT, which is beneficial for the flame retardant properties. However, due to its low crystallization speed, the presence of PET increases the difficulty of releasing a molded article from the mold. Accordingly, the amount of the PET in the thermoplastic composition according to the invention is selected to be not too large. Preferably, the amount of the PET with respect to the total polyester in the thermoplastic composition is at most 70 wt%, for example 50 to 70 wt% or 0 to 50 wt% or 1 to 40 wt%.Preferably, the total amount of the PBT and the PET with respect to the total polyester in the thermoplastic composition is at least 90 wt%, at least 95 wt%, at least 98 wt%, at least 99 wt%, at least 99.5 wt%, at least 99.9 wt% or 100 wt%.At least part of the polyester, polyalkylene terephthalate, PBT or PET may be a recycled polyester. Preferably, the polyester comprises PET and at least part of the PET is recycled polyethylene terephthalate.In some embodiments, the polyester further comprises PET and the melamine compound is melamine polyphosphate. The use of melamine polyphosphate as the melamine compound is beneficial for the flow properties of the thermoplastic composition according to the invention.(B) Glass fibersThe thermoplastic composition according to the invention comprises glass fibers.The amount of the glass fibers in the thermoplastic composition according to the invention is 10 to 45 wt%, preferably 15 to 40 wt%, with respect to the total thermoplastic composition.Glass fibers typically have a modulus of greater than or equal to about 6,800 megaPascals, and can be chopped or continuous. The glass fiber can have various cross-sections, for example, round, trapezoidal, rectangular, square, crescent, bilobal, trilobal, and hexagonal. Glass fibers can be in the form of chopped strands having an average length of from 0.1 mm to 10 mm, and having an average aspect ratio of 2 to 5. In articles molded from the compositions, shorter lengths will typically be encountered because during compounding considerable fragmentation can occur.For some uses, it can be desirable to treat the surface of the glass fiber with a chemical coupling agent to improve adhesion to a thermoplastic resin in the thermoplastic composition. Examples of useful coupling agents are alkoxy silanes and alkoxy zirconates. Amino, epoxy, amide, or thio-functional alkoxy silanes are especially useful. Fiber coatings with high thermal stability are preferred to prevent decomposition of the coating, which could result in foaming or gas generation during processing at the high melt temperatures required to form the compositions into molded parts.For compositions ultimately employed for electrical uses, it is preferred to use fibrous glass fibers comprising lime-aluminum borosilicate glass that is relatively soda free, commonly known as "E-glass". The glass fibers may be made by standard processes, such as bysteam or air blowing, flame blowing and mechanical pulling. Preferred glass fibers for plastic reinforcement may be made by mechanical pulling. The diameter of the glass fibers is generally about 1 to about 50 micrometers, preferably about 5 to about 20 micrometers. Smaller diameter fibers are generally more expensive, and glass fibers having diameters of about 10 to about 20 micrometers presently offer a desirable balance of cost and performance. In preparing the molding compositions, it is convenient to use the filamentous glass in the form of chopped strands of about one-eighth to about 2 inches long, which usually results in filament lengths between about 0.0005 to about 0.25 inch in the molded compounds. Such glass fibers are normally supplied by the manufacturers with a surface treatment compatible with the polymer component of the composition, such as a siloxane, titanate, or polyurethane sizing, or the like.The thermoplastic composition according to the invention comprises a flame retardant composition.The amount of the flame retardant composition in the thermoplastic composition according to the invention is 10 to 20 wt% with respect to the total thermoplastic composition.The flame retardant composition comprises an antimony compound, an organo-bromo flame retardant agent and a melamine compound. The flame retardant composition may further comprise an anti-drip agent.Preferably, the antimony compound is selected from the group consisting of antimony trioxide (Sb20a), antimony pentoxide (Sb20s) and antimony-metal compounds such as sodium antimonate (Na2SbO4) and combinations thereof. Most preferably, the antimony compound is antimony trioxide (Sb2C>3).Preferably, the amount of the antimony compound in the flame retardant composition according to the invention is 5.0 to 20 wt%, preferably 8.0 to 15 wt%, with respect to the total flame retardant composition.Preferably, the amount of the antimony compound in the thermoplastic composition according to the invention is 0.5 to 3.0 wt%, preferably 1.0 to 2.0 wt%, with respect to the total thermoplastic composition.The flame retardant composition may be made using a masterbatch of the antimony compound, preferably having a matrix of PBT.Preferably, the organo-bromo flame retardant agent is a brominated polycarbonate or a brominated polycarbonate oligomer.Organo-bromo flame retardant (FR) agents useful in the practice of this invention include tetrabromobisphenol A polycarbonate oligomer, polybromophenyl ether, brominated polystyrene (Br-PS), brominated bisphenol A polyepoxide, brominated imides, brominated polycarbonate, poly (bromoaryl acrylate), poly (bromoaryl methacrylate), or mixtures thereof.Other suitable organo-bromo flame retardant agents are brominated polystyrenes such as polydibromostyrene and polytribromostyrene, decabromobiphenyl ethane, tetrabromobiphenyl, brominated alpha, omega- alkylene-bis-phthalimides, e.g., N,N'- ethylene-bis-tetrabromophthalimide, oligomeric brominated carbonates, especially carbonates derived from tetrabromobisphenol A, which, if desired, are end-capped with phenoxy radicals, or with brominated phenoxy radicals, or brominated epoxy resins.In other embodiments, the organo-bromo FR agent is selected from the group consisting of decabromodiphenyl ether (Deca-BDE), decabromodiphenyl ethane (DBDPE), poly(pentabromobenzylacrylate (Br-acrylate), tetrabromobisphenol A (TBBPA), TBBPA oligomer, hexabromocyclododecane (HBCD), polybromophenyl ether, tetrabromo bisphenol A- tetrabromobisphenol A diglycidyl ether (brominated epoxide), brominated polystyrene (Br-PS), brominated imide, brominated polycarbonate (Br-PC), 2,4,6- tribromophenyl terminated TBBPA, TBBPA carbonate oligomer, or combinations thereof.Preferably, the organo-bromo FR agent is selected from the group consisting of phenoxyterminated tetrabrombisphenol A carbonate oligomer (TBBPA) which is available as BC-52,CAS Reg. No. 71342-77-3 for instance, from ICL-IP; 2,4,6-tribromophenyl-terminated tetrabrombisphenol A carbonate oligomer, which is available as BC-58, CAS Reg. No. 71342773, from, for instance, ICL-IP; decabromodiphenylethane (DBDPE), CAS Reg. No. 84852-53-9, from, for instance, Albemarle Corporation; poly(pentabromobenzylacrylate) (Br- Acrylate) CAS Reg. No. 59447-57-3, from, for instance, ICL-IP; tetrabromo bisphenol A-tetrabromobisphenlo A diglycidyl ether (Br- Epoxy), CAS Reg. No. 68928-70-1 , from, for instance, Sakamoto Yakuhin Kogyo; brominated polystyrene (Br-PS), CAS Reg. No. 88497-56-7, from, for instance, Albemarle Corporation; brominated polycarbonate (Br-PC) which is a copolymer comprising units of bisphenol A (CAS Reg. No. 111211-39-3); and tetrabromobisphenol A, 24-29 percent bromine by weight (CAS Reg. No. 156042-31-8). More particularly, the brominated FR compound is selected from the group consisting of brominated polystyrene (Br-PS) and poly(pentabromobenzylacrylate (Br-Acrylate).Preferably, the amount of the organo-bromo flame retardant agent in the flame retardant composition according to the invention is 40 to 75 wt%, preferably 50 to 70 wt%, with respect to the total flame retardant composition.Preferably, the amount of the antimony compound in the thermoplastic composition according to the invention is 5.0 to 15 wt%, preferably 8.0 to 10 wt%, with respect to the total thermoplastic composition.Melamine compoundPreferably, the melamine compound is selected from the group consisting of melamine polyphosphate, melamine cyanurate, melamine pyrophosphate, melamine phosphate, and combinations thereof. More preferably, the melamine compound is melamine polyphosphate or melamine cyanurate, most preferably melamine polyphosphate. The use of melamine polyphosphate is advantageous for obtaining a composition with good mechanical properties and good flame retardancy.Preferably, the amount of the melamine compound in the flame retardant composition according to the invention is 5.0 to 40 wt%, preferably 10 to 30 wt%, with respect to the total flame retardant composition.Preferably, the amount of the melamine compound in the thermoplastic composition according to the invention is 0.5 to 10 wt%, preferably 1.0 to 7.0 wt%, with respect to the total thermoplastic composition.Anti-drip agentThe flame retardant composition may further comprise an anti-drip agent. In some embodiments, the thermoplastic composition according to the invention is free of an antidrip agent.The anti-drip agent may be a fibril forming or non-fibril forming fluoropolymer such as polytetrafluoroethylene (PTFE). The anti-drip agent may be encapsulated by a rigid copolymer, for example stvrene acrylonitrile resin (SAN). PTFE encapsulated in SAN is known as TSAN. Encapsulated fluoropolymers may be made by polymerizing the encapsulating polymer in the presence of the fluoropolymer, for example an aqueous dispersion.Preferably, the amount of the anti-drip agent in the flame retardant composition according to the invention is 0.0 to 10 wt%, preferably 5.0 to 8.5 wt%, with respect to the total flame retardant composition.Preferably, the amount of the anti-drip agent in the thermoplastic composition according to the invention is 0.0 to 3.0 wt%, for example 0.1 to 3.0 wt% with respect to the total thermoplastic composition.In some embodiments, the total amount of the antimony compound, the organo-bromo flame retardant agent and the melamine compound in the flame retardant composition is at least 90 wt%, at least 95 wt%, at least 98 wt%, at least 99 wt%, at least 99.5 wt%, at least 99.9 wt% or 100 wt% with respect to the flame retardant composition.In some embodiments, the total amount of the antimony compound, the organo-bromo flame retardant agent, the melamine compound and the anti-drip agent in the flame retardant composition is at least 90 wt%, at least 95 wt%, at least 98 wt%, at least 99 wt%, at least 99.5 wt%, at least 99.9 wt% or 100 wt% with respect to the the flame retardant composition.The thermoplastic composition may optionally further comprise a polycarbonate. Suitable examples and the preparation methods of the polycarbonate in the thermoplastic composition according to the invention are described in detail e.g. in

[0036] -

[0068] of WO2015136389, incorporated herein by reference.It is noted that the polycarbonate of component (D) is a polycarbonate which is not halogenated, i.e. a polycarbonate which does not contain halogen atoms.As stated above, it was observed that a polyester-based composition has a better flame retardancy in combination with the flame retardant composition according to the invention than a polycarbonate-based composition. Accordingly, the amount of the polycarbonate in the thermoplastic composition according to the invention is selected to be not too large and is 0 to 20 wt% with respect to the total thermoplastic composition, for example 0.1 to 20 wt% or 1.0 to 20 wt%.The amount of the polycarbonate in the thermoplastic composition according to the invention may e.g. be 0.0 to 10 wt%, 0.0 to 5.0 wt%, 0.0 to 1.0 wt% or 0.0 to 0.1 wt%.In some embodiments, the thermoplastic composition according to the invention is free of component (D), i.e. the total amounts of (A), (B), (C) and € is 100 wt% with respect to the composition.The total amount of the polyester and the polycarbonate in the thermoplastic composition according to the invention is at most 75 wt% with respect to the total thermoplastic composition.Preferably, the amount of the polycarbonate with respect to the total amount of the polyester and the polycarbonate in the thermoplastic composition according to the invention is at most 30 wt%, at most 20 wt%, at most 10 wt% or at most 5 wt%.(E) Further componentsThe thermoplastic composition of the present invention may optionally include additives which do not interfere with the previously mentioned desirable properties but enhance other favorable properties.Optional additives that may be compounded or blended into the composition of the invention in customary amounts include inert inorganic pigments, dyestuffs, lubricants, release agents, UV absorbers, UV stabilizers, anti-oxidants, anti-ozonants, stabilizers, stainproofing agents, anti-static additives, anti-microbial agents, melt viscosity enhancers, impact modifiers, quenchers, processing aids, and the like. The different additives that can be incorporated in the compositions are commonly used and known to one skilled in the art. Illustrative descriptions of such additives may be found in R. Gachter and H. Muller, Plastics Additives Handbook, 6th edition, 2009.The amount of the further components is 0.0 to 5.0 wt%.In some embodiments, the further components include talc. Talc may have the function of improving flame retardancy and may be used to replace part of the antimony compound in the flame retardant composition. Accordingly, in some embodiments, the amount of talc in the thermoplastic composition is 0.1 to 2.0 wt%.In some embodiments, the further components comprise talc. Talc has the function of improving flame retardancy of the thermoplastic composition according to the invention and may be used to replace part of the antimony compound in the flame retardant composition. Accordingly, in some embodiments, the amount of talc in the thermoplastic composition is 0.1 to 2.0 wt%. For example, the amount of talc in the thermoplastic composition is 0.1 to 2.0 wt% and the total amount of the talc and the antimony compound in the thermoplastic composition according to the invention is 0.5 to 3.0 wt% with respect to the total thermoplastic composition.In some embodiments, the further components comprise ethylene vinyl acetate (EVA). EVA has the function as an impact modifier and improves the mechanical properties of the thermoplastic composition according to the invention. Accordingly, in some embodiments, the amount of ethylene vinyl acetate in the thermoplastic composition is 0.5 to 3.0 wt%.Preferably, the thermoplastic composition according to the invention has or is selected to pass a flame test, wherein the flame test involves- molding the thermoplastic composition into a test specimen having a top main surface and a bottom main surface having dimensions of 150 mm x 150 mm and a thickness of 3 mm,- placing the specimen horizontally,- exposing the bottom main surface to a tip of a flame of 1 ,000 °C for 5 minutes using a heat source of a mixture of butane, propane and air and- determining that the thermoplastic composition passed the flame test if no hole is visually detectable on the top main surface and that the thermoplastic composition failed the flame test if a hole is visually detectable on the top main surface.Preferably, the thermoplastic composition according to the invention has or is selected to have any one or more of the following:- a melt volume rate of from 1.0 to 100 cm3 / 10min, preferably 10 to 100 cm3 / 10min, as determined in accordance with ASTM D1238 (250°C, 5 kg),- a tensile modulus of at least 2000 MPa, preferably from 2500 to 15000 MPa as determined in accordance with ASTM D638 at 23°C on injection molded test bars and a test speed of 5mm / min,- an Izod impact strength of at least 20 J / m, preferably from 30 to 1200 J / m or 30 to 200 J / m, as determined in accordance with ASTM D256 at 23°C on injection molded bars having dimensions of 63.5*12.7*3.18 mm and provided with a notch type.ArticlesThe invention provides an article comprising or consisting of the composition of the invention.Preferably, the article is selected from the group consisting of a battery housing, a battery cell bracket and a heat insulation assembly of a battery module for electric vehicles for electric vehicles. Preferably, the article passes the test according to GBT-31467.3-2015. Preferably, the article passes the test according to ISO 12405-3.The article may be obtained by molding the composition of the invention, such as by injection molding. The article may also be obtained by extrusion followed by thermoforming.The invention further provides an electric vehicle comprising the article according to the invention and one or more batteries contained in the article.Flame retardant compositionThe invention further provides a flame retardant composition comprising an antimony compound, an organo-bromo flame retardant agent, a melamine compound and optionally an anti-drip agent.The invention provides a flame retardant composition comprising from 5.0 to 20 wt%, preferably 8.0 to 15 wt%, of said antimony compound, from 40 to 75 wt%, preferably 50 to 70 wt%, of said organo-bromo flame retardant agent, from 5.0 to 40 wt%, preferably 10 to 30 wt%, of said melamine compound, from 0.0 to 10 wt, preferably 5.0 to 8.5 wt%, of said anti-drip compound, wherein the amounts are with respect to the total flame retardant composition.Preferably, the total of the antimony compound, the organo-bromo flame retardant agent, the melamine compound and the anti-drip agent is at least 90 wt%, at least 95 wt%, at least 98 wt%, at least 99 wt%, at least 99.5 wt%, at least 99.9 wt% or 100 wt% with respect to the total flame retardant composition.The invention further relates to use of the flame retardant composition in a glass filled polyester composition. The glass filled polyester composition may comprise polyester comprising or consisting of polybutylene terephthalate and glass fibers and optionally polycarbonate.It is noted that the invention relates to the subject-matter defined in the independent claims alone or in combination with any possible combinations of features described herein, preferred in particular are those combinations of features that are present in the claims. It will therefore be appreciated that all combinations of features relating to the composition according to the invention; all combinations of features relating to the process according to the invention and all combinations of features relating to the composition according to the invention and features relating to the process according to the invention are described herein.It is further noted that the term ‘comprising’ does not exclude the presence of other elements. However, it is also to be understood that a description on a product / composition comprising certain components also discloses a product / composition consisting of these components. The product / composition consisting of these components may be advantageous in that it offers a simpler, more economical process for the preparation of the product / composition. Similarly, it is also to be understood that a description on a process comprising certain steps also discloses a process consisting of these steps. The process consisting of these steps may be advantageous in that it offers a simpler, more economical process.When values are mentioned for a lower limit and an upper limit for a parameter, ranges made by the combinations of the values of the lower limit and the values of the upper limit are also understood to be disclosed.The invention is now elucidated by way of the following examples, without however being limited thereto.ExamplesPBT compositions FR-PBT1 to FR-PBT7 were made by melt mixing the materials of Table 1 in the amounts shown in Table 2. Components were pre-blended and the pre-blended powder was extruded using a twin extruder at following temperature conditions.Test plaques were molded for respective tests.Flexural tests were measured in accordance with the ASTM D790 standard at 23°C.Izod impact measurements were performed on notched bars at 23°C, in accordance with the ASTM D256 standard.MVR was measured in accordance with the ASTM D 1238 standard at 250°C under a load of 5kg with residence time of 5 minutes.Tensile tests were performed in accordance with the ASTM D638 standard at a speed of 5 mm / min.High temperature flame test was performed as follows:- molding the thermoplastic composition into a test specimen having a top main surface and a bottom main surface having dimensions of 150 mm x 150 mm and a thickness of 3 mm,- placing the specimen horizontally,- exposing the bottom main surface to a tip of a flame of 1 ,000 °C for 5 minutes using a heat source of a mixture of butane, propane and air and- determining that the thermoplastic composition passed the flame test if no hole is visually detectable on the top main surface and that the thermoplastic composition failed the flame test if a hole is visually detectable on the top main surface.In Table 1 , the time until the flame burnt through the specimen is also indicated.In Table 3, the measured temperature at the top main surface is indicated.The molding conditions for making the test specimen for the high temperature flame test was as follows:Table 1Table 2-1Table 2-2Table 2-2 shows the amounts of components with respect to the total flame retardant composition. Table 3It can be understood that the addition of the melamine compound to the flame retardant composition according to the invention allowed the high temperature test to be passed. Use of MPP resulted in better mechanical properties (Table 2-1) and better flame retardancy (Table 3) than use of MCA at the same amount.The use of the melamine compound in the flame retardant composition resulted in some decrease in the MVR of the thermoplastic composition. When the thermoplastic composition comprises PET in addition to PBT, the MVR was higher when the melamine compound was MPP.Polycarbonate compositions FR-PC1 and FR-PC2 were made by melt mixing the components of Table 4 in the amounts shown in Table 4 and various properties of these compositions were measured as shown in Table 5. Table 5 also contains the results of FR-PBT1 of T able 2 for comparison.Table 4Table 5All of these compositions of Table 5 failed the flame test at 1000 °C. However, the burn through time (time until a hole became visually detectable on the top main surface) is shorter with the polycarbonate compositions than with PBT composition.

Claims

CLAIMS1. Thermoplastic composition comprising, based on the weight of the thermoplastic composition,(A) from 40 to 60 wt.% of polyester comprising or consisting of polybutylene terephthalate,(B) from 10 to 45 wt.% of glass fibers,(C) from 10 to 20 wt.% of a flame retardant composition comprising antimony compound organo-bromo flame retardant agent melamine compound and optionally anti-drip agent(D) from 0 to 20 wt.% of polycarbonate and(E) from 0 to 5.0 wt.% of further components wherein the total amounts of (A) to (E) is 100 wt.% with respect to the composition, wherein the thermoplastic composition is selected to pass a flame test, wherein the flame test involves- molding the thermoplastic composition into a test specimen having a thickness of 3 mm and a top main surface and a bottom main surface having dimensions of 150 mm x 150 mm,- placing the specimen horizontally,- exposing the bottom main surface to a tip of a flame of 1 ,000 °C for 5 minutes using a heat source of a mixture of butane, propane and air and- determining that the thermoplastic composition passed the flame test if no hole is visually detectable on the top main surface and that the thermoplastic composition failed the flame test if a hole is visually detectable on the top main surface.

2. The thermoplastic composition of claim 1 , wherein the thermoplastic composition has or is selected to have any one or more of the following:- a melt volume rate of from 1.0 to 100 cm3 / 10min, preferably 10 to 100 cm3 / 10min, as determined in accordance with ASTM D1238 (250°C, 5 kg),- a tensile modulus of at least 2000 MPa, preferably from 2500 to 15000 MPa as determined in accordance with ASTM D638 at 23°C on injection molded test bars and a test speed of 5mm / min,- an Izod impact strength of at least 20 J / m, preferably from 30 to 1200 J / m or 30 to 200 J / m, as determined in accordance with ASTM D256 at 23°C on injection molded bars having dimensions of 63.5*12.7*3.18 mm and provided with a notch type.

3. The thermoplastic composition of any one or more of claims 1 - 2, wherein the polyester comprises at least 40 wt.%, based on the weight of the polyester, of polybutylene terephthalate.

4. The thermoplastic composition of any one or more of claims 1 - 3, wherein the polyester further comprises polyethylene terephthalate wherein preferably at least part of the polyethylene terephthalate is recycled polyethylene terephthalate.

5. The thermoplastic composition of any one or more of claims 1 - 4, wherein the flame retardant composition comprises from 5.0 to 20 wt%, preferably 8.0 to 15 wt%, of said antimony compound, from 40 to 75 wt%, preferably 50 to 70 wt%, of said organo-bromo flame retardant agent, from 5.0 to 40 wt%, preferably 10 to 30 wt%, of said melamine compound, from 0.0 to 10 wt, preferably 5.0 to 8.5 wt%, of said anti-drip compound, wherein the amounts are with respect to the total flame retardant composition.

6. The thermoplastic composition of any one or more of claims 1 - 5, wherein the antimony compound is selected from the group consisting of antimony trioxide (Sb20a), antimony pentoxide (Sb20s) and antimony-metal compounds such as sodium antimonate (Na2SbC>4) and combinations thereof, preferably antimony trioxide.

7. The thermoplastic composition of any one or more of claims 1 -6, wherein the organo- bromo flame retardant agent is a brominated polycarbonate or polycarbonate oligomer.

8. The thermoplastic composition of any one or more of claims 1 - 7, wherein the melamine compound is selected from the group consisting of melamine polyphosphate, melamine cyanurate, melamine pyrophosphate, melamine phosphate, and combinations thereof, preferably melamine polyphosphate.

9. The thermoplastic composition of any one or more of claims 1 - 8, wherein the amount of the polycarbonate in the thermoplastic composition is 0.0 to 10 wt%, 0.0 to 5.0 wt%, 0.0 to 1.0 wt% or 0.0 to 0.1 wt%.

10. Article comprising or consisting of a thermoplastic composition comprising, based on the weight of the thermoplastic composition,(A) from 40 to 60 wt.% of polyester comprising or consisting of polybutylene terephthalate,(B) from 10 to 45 wt.% of glass fibers,(C) from 10 to 20 wt.% of a flame retardant composition comprising antimony compound organo-bromo flame retardant agent melamine compound and optionally anti-drip agent(D) from 0 to 20 wt.% of polycarbonate and(E) from 0 to 5.0 wt.% of further components wherein the total amounts of (A) to (E) is 100 wt.% with respect to the composition, wherein the article is selected from the group consisting of a battery housing, a battery cell bracket and a heat insulation assembly of a battery module for electric vehicles.11 . An electric vehicle comprising the article of claim 10 and one or more batteries contained in the article.

12. Flame retardant composition comprising from 5.0 to 20 wt%, preferably 8.0 to 15 wt%, of said antimony compound, from 40 to 75 wt%, preferably 50 to 70 wt%, of said organo-bromo flame retardant agent, from 5.0 to 40 wt%, preferably 10 to 30 wt%, of said melamine compound, from 0.0 to 10 wt, preferably 5.0 to 8.5 wt%, of said anti-drip compound, wherein the amounts are with respect to the total flame retardant composition.

13. Use of the flame retardant composition of claim 12 in a glass filled polyester composition.

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