Title of Invention	"FLAME RETARDANT THERMOPLASTIC COMPOSITION"
Abstract	The invention relates to a flame retardant thermoplastic composition comprising (i) a thermoplastic elastomer comprises a copolyester elastomer comprising (a) hard blocks and soft blocks consisting of segments of hard and soft polyester polymers linked by urethane groups and/or (b) hard blocks consisting of segments of a hard polyester polymer and soft blocks consisting of a long chain aliphatic dicarboxylic acid residue and/or a long chain aliphatic diol residue, wherein the hard and soft blocks are optionally linked by urethane and/or ester groups and (ii) a halogen free flame retardant system comprises a nitrogen containing flame retardant. The invention further relates to moulded parts made from the said composition.

Title of Invention

"FLAME RETARDANT THERMOPLASTIC COMPOSITION"

Abstract

The invention relates to a flame retardant thermoplastic composition comprising (i) a thermoplastic elastomer comprises a copolyester elastomer comprising (a) hard blocks and soft blocks consisting of segments of hard and soft polyester polymers linked by urethane groups and/or (b) hard blocks consisting of segments of a hard polyester polymer and soft blocks consisting of a long chain aliphatic dicarboxylic acid residue and/or a long chain aliphatic diol residue, wherein the hard and soft blocks are optionally linked by urethane and/or ester groups and (ii) a halogen free flame retardant system comprises a nitrogen containing flame retardant. The invention further relates to moulded parts made from the said composition.

Full Text	2 FLAME RETARDANT THERMOPLASTIC COMPOSITION The invention relates to a flame retardant thermoplastic composition comprising a thermoplastic Eastover and a halogen free flame retardant system and to a mounded part made thereof, more particular to a flexible thermoplastic composition having good flame retarding properties wet-heat resistance and mechanical properties and also more particular to mounded parts selected from mechanical parts, electric and electronic parts, automobiie oarts, and housings and other parts of, for example, office automation apparatuses and. household electronic appliances. Flame retardant -.thermoplastic composition comprising a thermoplastic elastomer and a halogen free flame retardant system and; moulded parts at least oartly made and consisting thereof, are known from US patent US-5,298,544. US-5,298,544-describes a flame retardant thermoplastic moulding composition consisting essentially of a thermoplastic resin and a flame retardant. The thermoplastic resin is a copoiyetherimide ester or a copolyether ester or a blend thereof. The copolyetherimide ester and the copolyether ester are both thermoplastic.elastomers. The flame retardant is magnesium carbonate or a bienc of magnesium carbonate and saicium carbonate having a combination of zinc Donate or zinc oxide or a blend of zinc borate anc zinc oxide. The Known compositions of US-5,298,544 show flame retardancy properties according to UL-94 standard complying with atypical V2 rating for the copolyethenmiae ester elastomer and VI for the copolyether ester elastomer. For these ratings high leadings of flame retardants of aoout 50 wt.%, relative to the total weight of the moulding composition are used. The said known moulding compositions further comprise a stabilizer package in an amount of about 1 A wt.%, relative tc the total weight of the moulding composition and show eiongation-at-oreak values in tensile test according tc ASTM D638 close to 25%. A disadvantage of the known compositions of US-5,298,544 is -that in many applications of. moulded parts made of flame retardant thermoplastic compositions, such high loadings and/or iow elongations are not acceptable, whereas in particular cases a V2 or VI rating is insufficient and a V'O rating is required. The-aim of the invention is tc provide a flame retardant thermoplastic composition comprising a thermoplastic elastomer and a halogen free flame retardant system and a moulded part made thereof, which do not show these disadvantageous or in lesser extent, more particular the invention is aimec at a flame retardam thermoplastic composition and a moulded part made thereof, which show a V2 rating, and preferably a V1 rating or even a VO rating according to UL-94-V standard at much lower filler loadings, meanwhile having higher elongations than the known compositions. A further requirement is that the compositions should have a good hydrolysis resistance under hot, humid conditions. This aim has been achieved with the flame retardant thermoplastic composition according to the invention ana the moulded part made thereof, wherein (i) the thermoplastic elastomer comprises a copolyester elastomer comprising (a) hard blocks and soft blocks consisting of segments of hard and soft polyester polymers linked by urethane groups or (b) hard blocks consisting.of segments of a hard polyester polymer and soft blocks consisting of a long chain aiiphatic dicarboxylic acid residue and/or a song chain aliphatic, diol residue, wherein the hard?and: soft blocks are optionally linked oy urethane groups and (ii) the halogen free flame retarcant system comprises a nitrogen containing fiame retardant. The effect of flame retardant thermoplastic composition according to invention and the moulded pan made thereof, comprising the said copolyester elastomer with (a) hard blocks anc soft blocks consisting of segments of! hard and soft polyester polymers iinKec by urethane groups or with (b) nard blocks consisting of segments of a hare polyester ootymer and soft blocks consisting of a long chain aliphatic dicarbcxyiic acid residue and/or a long chain aiipnatic did residue, and and/or a long chain aiipnatic diol resiaue wnerein the hard and soft blocks are optionally linked oy urethane groups and wnerein the halogen free flame retardant system comprises a nitrogen containing fiame retardant, is that the thermoplastic composition has a flame retardancy performance complying with V2, VI or even VO ratings according to the JL-94-V wnicr ratings are obtained at loadings of the flame retardant system much lower than usee for the flame retardant system in the known composition meanwhile also showing a mucn nigher elongation at break than the known composition of JS-5.298.544 having a. comparable-flame retardancy performance. Surprisingly, the mecnanicai properties of the copolyester elastomer used in the fiame retarcant thermoplastic composition according to the invention is affected only in' iimited extent by the presence of the nitrogen containing flame retardant. in sc far there is such a negative effect, i.e. reduction ;n elongation at creak, or tensile strength, this effect" is certainly limited, whereas in other cases this effect is clearly-positive, exnibited by an increased elongation whiie the Tensile strength at break is maintained at the same good level. This is even more surprising in view of the fact that nitrogen containing flame retardants, such as meiamine based flame retaraants and in particular melamine cyanurate, are known to negatively affect the mechanical properties in polymer compositions, certainly when used as the only flame retardant and in sufficiently high amounts for obtaining good flame retardancy properties. A further surprising effect is that mechanical properties of the flame retardant thermoplastic composition according to the invention are also retained, after treatment for a longer period under hot, humid conditions, at a level comparable to that of the original copoiyester elastomer with hard PIOCKS anc soft blocks corresponding with the features (a) or (b) as described above. The-fiame retardant thermoplastic composition according to the invention also; shows better flame retardancy properties than corresponding compositions comprising a copolyether ester elastomer as used in the known composition of US-5,298,544 in combination with nitrogen containing flame retardants, in that either the flame retardancy is better when using the same type and amount of the nitrogen containing flame retaraants ana/or a VO rating is ootainec at lower loadings of the nitrogen containing flame retardants. if such a rating can be obtained at all for the corresponding composition comprising the copolyether ester elastomer. A further difference in favour of flame retardant thermoplastic comoositiori according to the invention is that the mechanical oropenies of the corresponding flame retardant thermoplastic composition comprising the copolyether ester elastomer are certainly affected negatively by the nitrogen containing flame retaraants, exhibited by Sower values for elongation and tensile strength at oreak, which negative effect is already substantially at loading levels far oelow the level at which a VC rating is obtained if any. In further search for alternative flame retardant thermoplastic compositions, aisc other flame retardants have been tested in combination with tne coooiyether aster elastomer as used in the known composition. Among these other flame retaraants, a flame retardant system comprising aluminium diethylphcsphinate was found to be aoie to provide a solid VO-rating. For obtaining a solid VC, much higher loadings of the alternative flame retardant system was requirec than needec for the nitrogen containing flame retardants in the inventive compositions. Moreover, the said aluminium diethylphosphmate based flame retardant system nas a significant negative effect on the mechanical properties o; the copolyether ester aiastcmer. resulting in significantly lower values for both the elongation at break and iensiie strength compared, to-'the corresponding copolyether ester elastomer. Flame retardant thermoplastic composition comprising a thermoplastic elastomer and/or a halogen free flame retardant system comprising one or more-of the features of the compositions according to the invention have been described in different patents or patent appiications, as described below. None of these patents describe the inventive compositions or the effects thereof as according to the invention. EP-0102115-B1 describes polyester ester biock-copolymers with low melting soft blocks and high melting hard blocks composed of polyesters- and linked by urethane linkages, as may also be used in the flame retardant thermoplastic composition aceording to the invention. EP-0102115-B1 does not describe any flame retardant compositions based on the said polyester ester block-copolyrn$rs, let alone the flame retardancy or mechanical properties thereof. EP-0363321-B1 describes a flame retardant thermoplastic composition comprising melamine based flame retardants as halogen free flame retardant system. The meiamine based flame retardants consisted of melamine salts of phasphonic acids, which were typically tc be used in an amount of 1-100 pbw (parts by weight) relative; to 100 pbw of a-thermoplastic polymer. For the possible polymers that cart be useda&rttoe thermoplastic polymer many polymers are mentioned, including block-CQpoiijtettjeFesters, which as said above are thermoplastic elastomers. Various examples ate described in EP-0363321-B1 with flame retardancy test results showing different ratings. Only few examples, based on epcxy based poiyetber poiyurethane showed a V-0 rating. The mechanical croperties of those examples were not mentioned. However, none of the examples included a copolyetherester as mentioned in the above cited prior art, let alone copoiyester as used in the compositions according to the invention or the effect thereof. Flame retardant thermoplastic moulding compositions are also described in EP-037S237-A1. EP-0376237-A1 further describes moulded products made from the flame retardant thermoplastic moulding compositions, more particular "Kabelbinder" and Steckerieisten". The Known flame retardant thermoplastic moulding compositions of EP-037S237-A1 consist of a thermoplastic oolyamide (A), a thermoplastic polyetherester elastomer (B), meiamine cyanurate (C), and a filler. The amount of (B), only 0.45-15 wt.%, as well as the amount of (C), only 0.05-1,98 wt.%, both relative to the total of (A), ,'B) and ;C;, are very low. Meiamine cyanurate is a nitrogen containing-flame retardant. EP-0375237-A* explicitly states that the use of melamine cyanurate is problematic and wnen the amount oecomes too large: ;t influences the mechanical properties. EP-Q868478-B1 describes flame retardant elastomer compositions comprising a thermoplastic elastomer and one or more nitrogen containing flame retardants. The known flame retardant eiastomer compositions of EP-0S68478-81 are used for construction sheetings and have to comply with flame retardancy standards from the building industry (DIN 4102 B2). The nitrogen containing flame retardants are melamine condensates and melamine compounds, which are used in an amount of 5 to 30 wt.% based on the thermoplastic elastomer. Dreferred compounds are melamine cyanurate and meiam. The thermoplastic elastomer is chosen from the.group consisting of polyurethane block copolymers, polyetheramide oiock copolymers, polyefrrefestefr block copolymers and polyester ester biockcapolymers. The examples in EP-Q868478-B1 are with polyurethane block copolymers, poiyetheramide block copolymers, and poiyetherester block copolymers. Polyetherester block copolymers are preferred. None of the examples is with a polyester ester blockcopoJymer. Also no test results secorcMng to the UL-94-V standard are mentioned in EP-08B8478-B1. whereas DIN 4102 B2 is certainly not aiike and likewise much less critical than UL-94-V. Although:some of the copoiyester elastomers in the composition according tc the invention can be considered to be or are copoiyester elastomers, neither copoiyester elastomers-.as used in the composition according tc the invention, nor the advantageous effects thereof, are mentioned in EP-0868478-B1. Apart from construction sheetings nc other possible applications are mentioned. Thermoplastic copoiyester elastomers with hard blocks anc soft blocks linked by urethane linkages are describee in EP-0846712-81. The hare blocks in the copoiyester elastomers of EP-0846712-B1 are composed of poifyesters, whereas the soft blocks are composed of segments of a low melting aliphatic polycarbonate polymer. Reported possible applications of the block copolymers include pipes, hoses, cable and sheets, and in particular bellows and seals for automotive applications. The said block copolymers can be made flame retardant with flame retardants preferably melamine cyanurate. No amounts of flame retardants are mentioned and mechanical and flame retardancy properties of the flame retardant elastomers are not are not described in EP-0846712-B1. The copoiyester elastomer in the flame retardant thermoplastic composition according tc the invention comprises hare olocks consisting of segments of a. hard polyester polymer, also denoted herein as hard polyester poiymer segments.. Next to that the copoiyester eiastomer comprises soft biocKs consisting of segments of a soft polyester polymer, also denoted herein as soft polyester polymer segments, and/or soft olocks consisting of a long chain aliphatic dicarboxylic acid residue and/or a long chain aliphatic diol residue, herein denoted together also as soft aliphatic segment. The soft polyester polymer segments are iinked to the hard polyester polymer segments oy urethane linkages. The soft aliphatic segments' are iinked to the hard polyester polymer segments by ester, amide and/or urethane linkages, Ester linkages can be formed by reacting a long chain aliDhatic diol with a carboxyl functional polyester, or by reaction a long chain aliphatic diacid with a hydroxyl functional polyester. Amide linkages can be formed by reacting a long chain aliphatic diamine with a hydroxyl functional polyester. Urethane linkages can De formed by reacting a iong chain aliphatic diol with an isocyanate modified polyester, or by reaction a hydroxyl functional polyester with an isocyanate modified long chain aliphatic diol. Copolyester elastomer comprising, soft polyester polymer segments linked to the hard polyester polymer segments by urethane linkages ares generally considered as:being part of the group of copolyester ester elastomers. Such copoiyester ester elastomers can be made by letting react a low melting aliphatic polyester prepoiymer dioi and a high melting, aromatic, prepoiymer diol with di-isocyanate or by reaction an isocyanate capped prepoiymer with a prepoiymer dioi. For the isocyanate-capped: prepoiymer one can choose to: either- cap the low melting aliphatic polyester prepoiymer diol or high melting aromatic prepoiymer dioi with a di-isocyanate and than to let it react with the other dioi. Other members of the group of copoiyester ester elastomers include copoiyester elastomer comprising :soft polyester polymer segments iinkec to the hard ooiyester polymer segments by ester linkages. These latter copolyester ester elastomers can be made by separately preparing a low melting aliphatic polyester prepoiymer and a high melting aromatic prepoiymer, one of these prepolymers being a dioi and the other being a dicarboxylic acid, and then mixing the two ootymers and. an esterification catalyst at elevated temperature-in the melt under nitrogen. Once a transparent mixture is obtained, the esterification catalyst used in the orocess. must be deactivated. Such copolyester ester elastomers-with aster linkages are not suited for making flame retardant compositions with nitrogen containing flame retardants in that such compositions perform less good in one or more of the properties in which the flame retardant compositions excel, i.e. flame retardancy, good retention of eiastomeric properties upon addition of the nitrogen containing flame retardants as well as retention thereof after treatment under hot humic conditions The copoiyester elastomers with soft iong chain aliphatic segments linked to the hard polyester polymer segments by urethane and/or ester linkages, can be prepared in the same way as described above for the copoiyester ester elastomers with either urethane or ester iinkages, except that in stead of a soft polyester prepolymer dioi or soft polyester prepoiymer dicarboxylic acid a soft long chain aliphatic diol or diacid is used, and combined with, as suitable, with a polyester prepolymer dioi, diacid or isocyanate end-capped. The flame retardant thermoplastic composition according to the invention comprises a copoiyester elastomer comprising (a) nard blocks and soft blocks consisting of segments of hard and soft polyester polymers linked by urethane groups a&dfm (b) haed blocks consisting of segments.of a hare polyester polymer and soft blocks consisting of a iong chain alipnatic dicarboxylic acid residue and/or a iong chain aliphatic, diol residue, wherein the hard and soft blocks are optionally linked by urethane groups and (ii) the halogen free flame retardant system comprises a meJamine based flame retardant. The polyester polymer segments ;n the nard stocks suitably consists of repeating units derived from at least one alkylene dioi and at teast one aromatic or cycioaiiphaticdicarboxyiic acid. The: aromatic dicarboxylic acid in these polyester segments suitably is selected from-the group consisting of terephthaiic acid, isophthaiic acid, phthaiic acid, 2.6-naphthatenedicarbaxyiic acic and 4.4-djphenyldicarDoxyiic acid, and mixtures thereof. Preferably, the aromatic dicarboxylic acid comprises terephthaiic acid, more preferably consists for at least 5C mole %, still mere preferably at least 90 mole %, or even fuily consists of terephthaiic acid, relative tc the totai molar amount of dicarbaxyiic acid in the hard polyester polymer segments. The alkylene diol ir. the hard polyester segments preferably is a dioi with 2-15, and particularly with 5-10 carbon atoms. The alkylene diol suitably is selected from the group consisting of ethylene glycol, oropyiene glycol, butyiene glycol, 1,2-hexane diol, 1,5-nexamethyiene dioi, 1,4-outane diol. benzene dimethanol. cyclonexane diol, cyclohexane dimethanoi. and mixtures thereof. Preferably, the aikylene diol comprises ethylene glycol and/or 1,4-butane diol, more preferably . consists for at least 50 moie %, still more preferably at least 3C mole %, or even fully consists of ethylene glycol and/or l.-i-outane dioi, relative to the total molar amount of alkylene diol in the polyester oclymer segments In a preferred embodiment of the invention the polyester polymer segments in the hard blocks consist for at least 90 mole %, relative to the total molar amount of dicarboxyiic acid and alkyiene diol in the hard blocks, of repeating units derived from 1,4-butane diol and terephthalic acid. The poiyester polymer segments in the soft blocks suitably consists of repeating units derived from at least one alkyiene dioi and at least one aliphatic dicarboxyiic acids, and/or from at ieast one lactone and/or hydroxy! functional aiiphatic carboxyiic acid. Suitable aliphatic diols include ethylene glycol, 1,4-butanedioi, 1,5-pentanediol, 1,6-ftexanediol, 2,2-dimethyM,3-propanedioi, and mixtures thereof. Also other glycols, such as 1,3- or 1,4-cyclohexanediol or i ,3- or ' ,4-bis(hydroxymethyl)-cyc!ohexane, may be incorporated into the ;ow melting components. Under some circumstances, for instance to increase the melt viscosity of the endrproduct, it may be recommenaed to incorporate some small amount of higher functional compounds. Examples of such compounds are trimethylol ethane, trimethyiol propane and hexane trioi. Preferably, the aiiphatic dioi in the soft poiyester polymer segments comprises T,4-butarTedioi, 1,5-pentanedioi, 'S-hexanedioi. 2,2-aimethyt-1,3-prapanediol and-mixtures thereof in an amount of at ieast 5C mole %, still more preferably at least 70 mole %, or even more preferably at least 90 mole%, relative to the total moiar amount of aliphatic dioi in the soft poiyester polymer segments, or even consists for 100 % of the said aiiphatic diois. Suitable aliphatic dicarooxylic acias are, for example, adipic acid, glutaric acid, pwneiic acid, suberic acid, isoseoacic acid and ncinoleic acid. Aiso aiiphatic dicarboxyiic acids having hetero atoms, such as thiodipropionic acid may be used in the low melting afunctional compounds, in addition there still may be mentioned oydcaliphatie dicarooxylic acids such as i ,3- ori ^.-cyclohexane dicarboxyiic acid and: terephthalic acid and isophtnalic acic, wnich may be ccmonsed in the soft polyester segments in small amounts. Preferably, the dicarboxyiic acid in the soft poiyester polymer segments compnses adipic acid, more preferably consists for at least 50 mole %, still more preferably at least 70 mote %, or even at ieast 90 mole%, relative to the total molar amount of dicarboxyiic acid in the soft poiyester polymer segments, or even consists for 100 % of adipic acid. Other than being compcsec of trie reaction products of short-to- medium-long chain aliphatic diols and aliphatic dicarboxylic acids, the low melting soft blocks may as well entirely or partly be composed of lactones, such as substituted and unsubstituted caprolactone or butyrolactone. The procedure for preparing the iow melting oolyesters is known per se and similar to that used for preparing high melting polyesters. It may be realized for instance by pdiycondensation of polyfunctional, preferably Afunctional alcohols, hydroxycarbaxylic acids, and lactones. By a proper choice of the mixing ratio of the above-mentioned components any desirable molecular weight and number and type of terminal groups may be obtained. The long chain aliphatic diol from which the soft segments may be derived* may le-any aiiphatic polymer terminated with nydroxyl groups. Suitably, the. long- chain aiiphatic diol is a.polyene diol. for example a polybutadiene diol or a hydrogenatediderivative thereof. Suitably, the long chain aliphatic diol has a molecular weight varying over a large range, and which molecular weight may be as low as. 400, or even lower, and as high as-2000., or even higher. Preferably long chain aliphatic diol has a moiecular weight in the range of 500 -1.200, more preferably 800-1200. A higher molecular weight has the advantage that the eiastomeric properties are further enhanced. The long chain aliphatic diol, more specifically the residues thereof can be present in the copoiyester elastomer in an amount varying over a large range, and preferably in a range of 30 - 70 wt.%, preferably 4C-65'wt.'%, more;preferably 50-6Gwt.%, reiattvetQ the weight of the copoiyester eiastomer. Where the-long chain aliphatic diol can be represented by the formula HC-R-OH, the residue thereof is represented by the formula f-O-R-O-j, which latter formula ;s used for the calculation of the amount. The long chain aiiphatic diamine, from which the soft segments may be derived; may.be any aiiphatic diamine which is aole to phase separate from the hard block polyester segments, thus providing the copoiyester elastomer with eiastomeric properties. Suitably, the long chain aliphatic diamine is a compound corresponding with the lomg; chain aiiphatic dioi, and preferred embodiments thereof, described above, wherein the terminal hydroxyl groups have beer, replaced by primary anine groups. The long chain aiiphatic diacid from wnich the soft segments may be derived, may be any aliphatic diacid which is able tc phase separate from the hard biock polyester segments, thus providing the copoiyester elastomer with eiastomeric properties. Suitably, the long chain aliphatic diacid has a moiecuiar weight varying over a large range, and which moiecuiar weight may De as low as 400, or even lower, and as high as 1QQG, or even higher, Preferably long cnain aliphatic diacid has a molecular weight in the; range of 500 -800, more preferably 550-700. A higher moiecuiar weight has the advantage that phase separation is improveG and elastomeric properties are enhanced. The long chain aliphatic diacid, more specifically the residues thereof can be present in the copoiyester elastomer in an amount varying, over a large range, and,preferably in a range of 30 - 70. wt.%, preferably 40-65 wt.%, more preferably 50-60wt.%, reiatiseto the weight of the copoiyester elastomer. Where the long chain aiptetiedJ2W^cafT&ei:re\|jreserTted by the formula HO(-0)C-R-C(0)OM, tfce- residue-themof is represented-by the formula [-0(C)-R-(C)0-3, which latter formuja is used for the calculation of the amount. Examples of suitable long chain aliphatic diacid are compounds known as diner fatty acids, for example derived from oleic and iinoleic acids. The long chain aiiphafediaeids may suitably be linear or brancheo. Dimer fatty acids, are available^ farsSKafnpie;, under trade name Pnpoi from Uniqema, The Netherlands. The ucethane linkages in the polyester elastomer suitably consists of refseating;uwlf-derivedfram atieast one aliphatic or aBcyciic diisocyanate and/or-at least ®ne aiDEta-icdiisacyanate. The urethane linkages can be represented by the formula [-(Q)&(H)'f4-R--N(H}-C(0}-], wherein R is an aliphatic group, an aiicyclic or an aromatic group;, which groups can optionally be heteroatom substituted. Examples of suitable atipnatic diisocyanates are nexamethylene diisocyanate, dimethyl hexamethylene diisocyanate. trimethyi nexamethylene dttsecyanafe, metaMy4ytene diisocyanate, paraxylylene diisocyanate, tetfamethyiene dnsocy-aKjale:' Suifeabie diisocyanates having an aiicyclic group include isophoron diisocyarralSi dicyclohexytmethane diisocyanate ana 1 4-cyclohexane diisocyanate. Examples of suitable;aromatic diisocyanates include: 1 -cnioro-2,4~pnenylene diisocyanate, 2,4-toiuene diisocyanate, ietramethylpherryiene diisocyanate, dipheny4methane-4;4'-diisocyanate (MDl), metaphenyiene diisocyanate, paraphenyiene diisocyanate, naphthalene-1,5-diisocyanate, diphenyM ,4'-diisocyanate,\ phenyimethaBe^4,4'-o3isocyanate, bipnenyldirnethylrrtethane-4,4'~diisocyanate, benzophenone-4,4'-diisocyanate, oipnenyietner diisocyanate and bipnanyisulpmde diisQcyanate,-ar3,-dicneth.yldipheny!-4,4'-diisocyanatev S.S'-dimetnoxydiphenyM^'-diisocya^ate■, 3,3'-d.ichiarod!pbenyi-^,4'~diisocyanate, 2.3'-dicnlorodiphenyi-4 4!- diisocyanate, benzofuran-2,7-diisocyanate. Preferably, the diisocyanate from the urethane linkages are derived compriae djphenylroetb.ane--4,4'-diisocyanate (MDI), more preferably in an amount of at least 50 mole %, still more preferably at least 70 mole■%, or even at least 90 moie%, relative to the total molar amount of diisocyanate in the soft polyester polymer segments, or even consists for 100 % of diphenylmethane-4,4'-diisocyanate MDI. The copolyester elastomer in the flame retardant composition according to tee invention preferably comprises hard and soft segments linked by urethane linkages, more preferably the soft segments comprise or even consist of segments of a soft polyester polymer. The effect of the urethane linkages is that the performance of the compositions in the UL-94-V flame retardancy test i£ improved, and the minimum amount of melarnine based flame retardants needed for obtaining a V0 rating is reduced.while better mechanical properties, more particular a higher elongation-at-break is obtained. These effects are further enhanced with the soft segment comprise segments of a soft polyester polymer. Stilt more preferably, the urethane linkages are present in the copolyester elastomer m an amount in the range of 1-15 wt.%, relative to the total weight of theicapolyester elastomer, and wherein the weight of the urefiiane linkages based orr structural elements represented by the formula !-(Q)C-{H)N-R-N{H}-C(QH Copolyester elastomers comprising hard and soft polyester segments. linked by urethane linkages, as well as the synthesis, thereof, are described in EP-0:1X12115-61, which patent forms an mtegrai part of this invention by reference. In a preferred embodiment of the invention, the hard blocks of copolyester elastomer have a melting point (Tm) of at least 150°C, preferably at least 165 °C, 180'°C, 20Q.°C or even at least 22Q°C and the soft blocks have.a glass transition temperature'(Tg) of at most 2C°C. preferably at most 0°C. -20°C, -40°C: or even atmast-5Q°C, The. advantage of the copolyester elastomer having the said minimum Tm is. that it has better mechanical strength and better retention of the elongation upon treatment: with hot numid conditions, whereas a lower maximum Tg leads to mare flexible products with higher elongation. With the term melting point (temperature) is herein 'understood the temperature: measured by DSC with a heating rate of 1C°C/min falling, in the melting temperature range and showing the highest melting rate. With the term glass transition point is herein understood the temperature measured by CSC with a heating rate of 10°C/min falling in the glass transition temperature range and snowing the highest glass transition rate. in another preferred embodiment of the invention, the flame retardant thermoplastic composition has a hardness between 20 and 70 Shore D, preferably between 30 and SO, still more preferably 40 and. 50 Shore D. Next to the copoiyester elastomer, the flame retardant thermoplastic composition may comprise other thermoplastic polymer elastomers, such as polyetherester elastomers and polyetheramide elastomers, as well as other polymers, such polyesters, palyamides and polycarbonates. If any polymers other than the copoiyester elastomer are present, thermoplastic polymer elastomers are preferred. Preferably, tfte flame retardant thermoplastic composition- comprises the said copoiyester elastomer in an amount of at least 50 wt.%, more preferably at ieast 75vwt.%, 90 wt.% or even at least 95 wt.%, relative to the total weigtst of polymer in the^ffame-retardant thermoplastic composition. The effect of the higher copoiyester elastomer content is that the effect of the invention is further enhanced. Suitable nitrogen containing flame retardants, that can be usee in the flame retarded thermoplastic composition according to,the invention a re,, for example, flame, retardants based on triazines, guanidines, cyanurates, and isoc.ya$uraiesr and mixtures, and salts thereof. Suitable triazine based flame retardants are, for example, meiamine bassd.flame retardants, which include melamine, melamine condensation products, melamine cyanurate and melamine salts, and comDinations thereof. Suitable melamine condensation products are for example melam, melem, and'melort, and:higher condensation proaucts of meiamine. These condensation' products generally comprise mixtures of differeni oligomers of meiamine. As a. major component, melam, melem. and melon comprise respectively dimers, trimers and tettamers of melamine. Meiamine condensation products cars, for example, be obtained? with the process described in WC-A-96/16948. Suitable salts: of the nitrogen containing flame retardants are. for example, borates and oxalates, and salts of phosphor containing compounds, such as phosphates, phospinates and: phosphorates and aligomoric and polymeric derivatives thereof. Examples of suitable nitrogen and phosphor containing compounds are ammonium polyphosphate and melamine polyphosphate. Preferably the nitrogen containing flame retardant is a melamine based flame' retardant. The advantage thereof is that better flame retardancy properties are obtained as measured according to 'JL-B^-v standard ai the same or lower loadings, and that higher elongations are obtained at loadings with comparable flame retardancy performance according to JL-94-V. Suitable melamine based flame retardants include meiamine, melamine condensation products, melamine cyanurate and melamine salts, and combinations thereof. Examples of melamine salts include melamine (poly)phosphates, e.g. available under the trade name Melapur20C from Ciba Geigy, melamine borates and melamine oxalates. Mora preferably, the meiamme oased flame retardant comprises a melamine condensation product and/or melamine cyanurate, more preferably melamine cyanurate. The advantage of melamine cyanurate is that it provides an even that betSerfiatne retardancy properties are obtained at the same or iower loadings, and/or that elongations are better retained upon treatment under hot numid conditions. Melamine cyanurate is the reaction product of preferably equimolar amounts of melamine and cyanunc acid or isocyanuric acid. It can be made by conversion of aqueous solutions of the starting compounds at 90 to 10®°C. Melamine cyanurate is commercially available as a white product with a particle size distribution wherein the. particle size can van' over a iarge range, generally in the range of 0.1-100 pm. The me^ttnine cyanurate -'that is used is preferable of small particle size, or can be easily dtepeiraped" into small particles in a polyester continuous phase during mixing, Suitably, the melamine cyanurate has a particle size distribution with a median particle size (d50) smaller than about 25 micrometer (urn- and larger than 0.5 um; preferably the mediae, particle size d 50 is in the range of 1-15 urn, more preferably in the range of 2-10 um. Very suitably, the median particle size d50 is in the range of 2.5-5 um. With the median particle size d50 is herein understood the particle size, relative? to which 50 wt.% of the: particles have a smaller particle size and 50 wt.% of the particles a larger particle, This, median particle size can be determined as D50 according to ASTM standard D1321-89, method A. The nitrogen containing flame retardant may oe present In tne flame retardant thermoplastic composition according to the invention in an amount varying over a wide range, which amount may De as low as 7.5 wt.% or jower and also as high as 40 wt.% and-higher. Preferably, tne niirogen containing flame retardant is present in an amount between 7.5 and 40 wt.%, anc more preferably in the range of 10-35 wt.%, still more preferably 15-25 wt.%. Herein tne weignt perceniage (wt.%) of the nitrogen containing flame retardant is relative to the total weight of the flame retardant thermoplastic composition, ^he advantage of a higher minimum amount is that better flame retardant properties are obtained, whereas with a lower maximum amount better mechanical properties are obtained The flame retardant thermoplastic composition according to the invention may comprise, next to the nitrogen containing flame retardant, other flame retardant compounds or flame retardant synergists to further enhance the: flame retaedant prope#es of tire thermoplastic composition. For these other flame retardant compounds and flame retardant synergists, together indicated as other flame retardant components, any flame retardant compound suitable for use in thermoplastic elastomers or any ffame retardant synergist suitable for use in combination with nitrogen containing flame retardants may be used. Preferably these otherflame retardantcomp&nentsr are nalogen free. Preferably, these other flameretBrd&nt components, are-used in such an amount that the mechanical properties, in particular the elongation and/or the retention thereof upon treatment under hot humid conditions are not affected or oniy so in limited extent. Suitable types and amounts of these other flame retardant components can be determined by theperson skilled in ttreart of making flame retardant thermoplastic composition by routine experiments and testing. A flame retaedant.synergist is herein understood: to be s. compound thai further improves the.flame retardant properties of the inventive polyester composition, S&itebiy, the flame retaraant synergist is an inorganic compound such as talc, arnetat oxide-, a metal sulphide or a meta! borate. An example of a suitable metal borate is zinc., borate. Preferably, the other flame retardant components, if present at ail, are present in arramount of 0.01 -TO wt.%. more preferaoly 0.1-5wt.%, still more preferably 0.2-2 wt.%, refetive to. the totai weight of the thermoplastic composition. Most preferably thesamount is 0 wt.% i.e. there are nc other flame retardant components present. In addition to the constituents mentioned here above, i.e. the polymeric components-" and the flame retardant system, the flame retarded thermoplastiecamposition according to the invention may further campfrse one or more auxiliary addilives, such as fillers, reinforcing agents, stabilizers, processing aids, colouring agemts The fillers, reinforcing agents and other auxiliary additives that can be used in the flame retarded polyester composition may be any such compound G«waafeatsra% used inflame retardant. thermoplastic compositions. Fillers and reinforcinc agents generally consist of inoraanic fibrous materials and powder consisting of small particles, typically with a particle size beiow 1mm, preferably below 0.1 mm, more preferably below 10 urn. Suitable examples of fillers are magnesium carbonate, kaolin, quartz, calcium carbonate. Suitable reinforcing agents include-glass fibers and carbon fibres. The fillers and reinforcingvagents are suitably used in a total amount of up to and even exceeding 50 wt.% of the total composition. Preferably, fillers and reinforcing, agents are present in a total amount of 0-50 wt.%, more preferably 0,01-30 wt.%, or 0.1-20 wt.%, and most preferably 1-10 wt.%, relative to the total weight of the flame retardant thermoplastic composition. The-other auxiliary additives are suitably present in a total amount of 0-20 wt.%, more preferably 0,01-10 wt.%, or 0.1-5 wt.%, and most.preferably 1-3 wt.%, relative to the,.totai weight of the flame retardant thermoplastic composition Suitable stabilizers include, for example, trans-esterifieation inhibitors, UV-stabilizera-, heat stabilizers ana anti-oxidants, as well as combined thermo-oxidative stabilizers. Additives- suitable as heat stabilizer and/or and anti-oxidant are, for example, hincjered phenols, hydrochinones. Suitable UV-stabilisers are, for example, benzophenone. benzotriazoles, resorcinois, anc saiyciiates. Stabilizers are suitably present in a total amount of 0-5 wt.%, preferably O.OT-3 wt.%. or Q.05-2wt.%. and. most preferably 0.T-1 wt.%, relative to the totar weight of the flame retardant thermoplastic cam position. Suitable processing aias include mould release agentte, such as fatty acids and derivatives thereof, including: stearic acid, stearic alcohol and stearic amides, lubricants or viscosity reducers, and nucleating agents, such as talcum. These adsditives aresuitabiy used in a totai amount of 0-3 wt.%, preferably 0.01-2 wt.%. more preferably 0.1-1-wt.%, relative tc the total weight of the flame retardant thermoplastic composition. Suitable colouring agents include pigments, such as Itanium dioxide: aod carbon biaste, and dies, such as nigrosine. Colouring agents are afeo are suitably used in attjfiaiatnount-of 0-3 wt.%, preferably 0.01-2 wt.%, more preferably 0.1-1 wt.%; relative to ftmtotal weight of the flame retardant thermoplastic composition. In a specific embodiment of the invention, the flame retarded thermoplastecompositian is. a halogen free1 flame retarded thermoplastic composition, consisting; of A) a copolyester elastomer as according to claim 1 of the invention, and optionally B) one or more other polymeric components, wherein (A) is present in a amount of ai least 50 wt.% relative tc the total weight of (A) and (B), C) between 7.5 and 40 wt.% of a nitrogen containing flame retardant as according to claim 1 of the invention, and D) 0-10 wt.% of one or more other halogen free flame retardant components, E) 0-50 wt% of one or more fillers and reinforcing agents, and F) 0-20 wt.%. of one or more other auxiliary additives, wherein the weight percentages of (C), (D), (E) and (F) are relative to the'total weight of the flame retKderi thermoplastic composition, and wherein the sum of (A)-(F) is 100 %. In a- preferred embodiment of the invention, the flame retarded thermoplastic composition is a halogen free flame retarded thermoplasticcomposition, consisting of A). a, copBifsester elastomer comprising hard blocks and soft blocks consisting of segments of hardJand soft polyester polymers iinked by urethane groups, and optionally B); one or more other polymeric components, wherein (A) is present m a* amount of at least50. wt.% relative to the total weight of (A) and. (B), Q; betweerr7.5and 40 wt.% of a meiamine oased;flarne retardant, and D): 0-1G wt.% of one or more other nitrogen containing free flame retardants and/or other halogen free flame retardant components, E) 0-20 wt.% of one or more fillers and reinforcing.-agents, and F) 0-10 wt% of one or more other auxiliary additives, wherein the weight percentages of (C), (D), (E) and (F) are relative, to toe total weight of the flame retarded thermoplastic composition, and wherein the sum of (A)-(F) is 100 %. in a-rosre preferred embodiment of the invention, the flame-retarded thermoplastic: composition is a halogen free flame retarded thermoplastic composition, consisting of A) a?CQpc3%ester elasfomer comprising hard blocks and soft blocks consisting of segmewtsvof hard and soft polyester polymers iinked Dy urethane groups, and optionally B)' other polymeric components, wherein (A) is present in a amount of at least 50 w£.% Native to, the-total weight of (A) and (B), C) 15-35 wt.% meiamine cyanurate, and D) 0-5 wt.% of one or more other meiamine based flame retardant and/or other nitrogen containing flame retardant and/or other halogen free flame retardant components, E) Q-1CTwt.% of one or more fillers and reinforcing agents, and F) 0-5 wt.% of one or more other auxiliary additives, wherein teeweight percentages of (C), (D), (E) and (F) are relative to the total weight of the flame retarded thermoplastic composition, and wherein the sum of (A)-(F). is TOO %. The copolyester elastomers used in the flame retarded thermoplastic composition according to the invention, as well as these inventive compositions and awy-ppeS&FresteerafacdJFnemts.-thereof, can be made using conventional methods. The preparation of copolyester elastomers comprising hard blocks and soft blocks consisting of segments of hard and soft polyester polymers linked by urethane groups, is described; tor example in EP-Q102115-B1. For the preparation of the flame retarded thermoplastic composition, one can suitably use melt-mixing equipment, such as single screw extractors, double-screw extruders, Brabender mixers and Banburry kneaders. The inventive compositions are very suited for making moulaed parts by, means of'ssanous moulding techniques, including injection moulding and extrusion moulding and over moulding, in particular for the preparation of fiexibleimqulded'parts far various; high demanding technical applications. For these applications, the good fiame retafidancy properties in combination with the high elasticity and retention of mechanical properties upon treatment under hot humid conditions are very advantageous. The invention therefore also relates to the use of the flame retardant thermoplastic composition according to the invention in a moulding process for making am injection moulded part, an extrusion moulded part or an avermoulded. part. The invention also relates to a shaping process for making a moulded pan comprising, a step wherein the moulded part is shaped by injections moulding, or extrusion moulding of an elastomer composition according tc the invention, or any preferred erBtoadiment thereof, or overmoulding of an elastomer composition according. to the invenifcin, or any preferred, embodiment thereof over a core part. The invention also relates to a moulded part at least' partly made from a ffame-retardant thermoplastic elastomer composition according to the invention, or any preferred; embodiment thereof, oreferably being a an injection moulded part, an extrusion moulded, part or an over-mouloed part. In one preferred embodiment, the moulded part is an over- moulded part comprising, a core part over-moulded with a layer of the flame retardant thermoplastic elastomer composition according to the invention, e.g. PC/ABS structures avewnQulded with the flame retardant thermoplastic elastomer, electrical cable sheeting, multilayer hoses. In another preferred embodiment, the moulded part is an extrusion moulded past selected from the group consisting of monofilaments, e.g. for suspension seatings, eiecteical cafale sheeting, for example insulating layers and/or jacket layers, hoses, tubes, &g, convoluted tubes, air brake tubes, air ducts, and fuel tubes, seaiings, such as sounds:deadening profiles for window sealing, and alike. Frr a?farther preferred embodiment, the moulded part is an injection moulded part selected; from the group consisting of shoe ware, mechanical parts such as cable ties, wtotational and noise dampeners, electrical and electronic parts, e.g. connectors, aiiDwrabile parts, e.g. inboard boots and joint velocity boots (or jvc-boots), engine part,.eig. km noise gears, parts of and housing-for office automation apparatuses anelectrical household appliances, and parts for use in public transport such as boats,.busses, trains and airplanes. The moulded part according to the invention preferably, is a Met-Shaped-fait'at" least-partly made-from-and-conststing-of one or more flame retarding theran aplastic compositions according to the invention. With the term "Net-Shaped-Part" is herein understood a three dimensional fReesfanding structure explicitly not being a flat part or a sheet. With the term "at least partly made-from-and-consisting-of' is herein understood that the Net-Sftaped^Paft may have been made only from the said flame retardant thermoplastic compasMafT .awd;consequently will consist integrally of the said flame retardant thermoplastic:composition, or that one or more pans of the Net-Shapect-Part may have been made from the said flame retardant thermoplastic composition and consequently will?coftsistiolfthasaidflame retardant thermoplastic composition, whereas one or more other parts oithelfet-Snaped-Part may have been made from another composition or other com positions, which other composition or compositions may optionally have been blended wtfrttr© said flame retardant thermoplastic composition, and consequently these oneor 'mere other partswill consist of the said other composition; or compositions optionally blended with the said flame retardant thermoplastic composition. The invention is further illustrated with the following, examples and comparative experiments. Materials TPE-E-1 Polyetherester elastomer comprising hard segments consisting of polybutyleneterephthalate segments and soft segments consisting of EQ/PQ- poiyether blockcopolymer: hardness Shore-D 36. TPE-E-2 Poiyetherester elastomer comprising hard segments Consisting of pal^au^eneterephthalate segments and soft segments consisting of FTMG poiyether soft segments; hardness Shore D40 TPE-E-3 Polyasterester consisting, of hard segments consisting of palytotyleneterephthalate segments and soft segments consisting of paiytactone segments linked with urethane groups; haadness Shore D55„ TPE-E-4 Polycarbonate ester elastomer consisting of paijstbM^ieneterephthalate hard segments and soft segments consisting of polycarbonate soft segments linked with iFethane groups. Mecy: Melamine cyanurate (MC50; particle size distribution with a d50 of aoout 4.2 ^m and a d98 of about 45 urn) Exolii 1312: Bienctaf aiummium diethylphosphinate, melamine pol and Zinc Borate Clariant Moulding compositions of Examples i-Vi (EX-1 - EX-V! J according to the invention, and Comparative Experiments. A-L (CE-A - CE-L) were prfpated and tested as descritJeri below. The compositions and test results are--presented in Tables 1 and 2. CompoundirTq- For the preparations of moulding compositions, ingredients were coin pounded m ratios, as indicated in Table 1. The moulding compositioits, were prepared- by raeH^blencting. the TPE-E'S with the flame retardant compofiefits and stabilizer pactaagpon aZSK 30/33 twin-screw extruder with screw speextZQO rpfrt, throughput TfJkgmr, and melt temperature regulated at 250°C, extruding tte melt from the extruder tttrougtr a> die-, and cooling and granulatisg the melt The giiprwles obtained by compounding' in the extruder were dried for 24 nours at 120°C, prior to further use.21 Moulding of test samples Test samples for Testing the mechanical properties and theflame retarda-ncy- properties were prepared on an injection-moulding, machine: of typfiEngel 80 A. For the injection moulding set temperatures of 235-245°C were used. The mould temperature was 90°C. Cycle times for the test specimens were about 50 sec. Test methods Mechanical properties: Tensile tests were performed according to ISO 527/1A using dry-as-mouldec samples. Dimensions of tensile test specimens: thickness 4 mm. Flame retardancy: Sample preparation and testing was performed according to UL-94-V standard, with lest specimens hawing a thic'Kness of 1.6 mm. Hydrolysis resistance: for this test thersampie cable is kept in a. temperature cyeiing chamber for 95 hours at S5°C and 95% relative humidity. After this conditioning, the mechanical properties of the test specimens were tested as described above. Compounds with the oompositions ofExamDies -V! (EX-i - EX-V!) according to the invention anc: Comparative Experiments A-L (CE-A - CE-L) were prepared: and tested-as describee above. The compositions anc test results- are presented in Tables 1 and 2. (Table remove) TfNf f: e>empq§itjpns On p§rts by weight) and test results for Comparative Experiments D-L CLAIMS Flame retardant thermoplastic composition comprising, polymer comprising a them?epJastic elastomer and a halogen free fiame retardant system characterized in that (i) the thermoplastic elastomer comprises a copoiyester elastomer comprising (a) hard blocks consisting of segments of hard polyester polymers and soft blocks, consisting soft polyester polymers linked by urethane- groups and/or (b} hard blocks consisting of segments of a hard polyester polymer and soft blocks consisting of a long chain aliphatic djcarhoxyiic acid residue, a. long chain aliphatic amine and/or a ions chain aliphatic dial residue, wherein the hard and’ soft blocks are; option ally linked by amide; ester and/or urethane groups and (ii) the- halogen free flame retardant system comprises a nitrogen containing: flame retardant. Flame retardant thermoplastic composition according to claim 1, wherein the copo^ester eiastomer comprises hard, blocks and soft blocks consisting of segments of hafd and: soft polyester polymers linked by urethane groups, Flarrfiferetardanttnemroplastic.composition according.to claim. 1 .or2, wnerein the csepalyester-ester eiastomer is present in^an amount of at least 50 wt. %, relBtae to the total weight of polymer in the composition. Flam retardant thermoplastic composition according to any oflciaims 1-3, wnssrein-the nitrogen containing fiame retardant comprises a meiamine based: flarna retardant. Flarrae?netapdant thermoplastic composition according to any oftciaims 1-4, wrtraprctte nitrogen containing flame retardant is present in aff-amount be\|y«»eEr 7.5 and 40wl.%, relative, to the totai weight of theffanje retardant tosanpaplststtc composition. Flame retardact thermoplastic, composition according to any of claims 1-5, consisting of A) t&e- copoiyester elastomer (i) of claim ', and optionally B) one or more other polymeric components, wherein (A) is piesent in a amount of at reast 50 wt.% relative to the total weight of (A\| and (B), and wherein the sum of (A) and (B) is 20-100. wt.%, relative to tie-total weight of the-flame-retardec thermoplastic composition, ) between 7.5 and 40 wi.% of tne nitrogen containing flame retardant (it) of claim 1. and optionally D) Q-1G wt% of ane or more other haiogen free flame retardant components, : E) CTr-5Q'wt.%-of one or more filters-and reinforcing- agents, and F) G-20 wt.%-.of one or more other auxiliary*additives, wheceirr the. sum of (A;-(F: is 100 % and wherein the weight; percentages of (C), (O), (E) and (F) are. relative to the total weight of the flacnef retarded. thermoplastic: composition. 7. Use of a fiame retardant thermoplastic composition according, to any of claims 1-6 iff a moulding process for making an injection moulded pat; an extrusion rnoufeted: parro? an overmouldec oart. 8t Shaoing. process for making a moulded-part comprising a step! wherein the rrtauki&c. parr is snaped by injection moulding or extrusion mo#dfeg of an etastomer comoositior. according to any of claims " -6, or overmoulding of an etestomer corriDosrtion according to any of claims i-6 over a core' pan. 9. Mauldec oar. at yeast cartly mace from a flame reiarcant ihernhapiastic elastomer comccsitior according ic any ofciaims '-c. oreferabiyoeing-a an injection mouJdec car . an extrusion moulded oar or ar over-mouidec pan.

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FLAME RETARDANT THERMOPLASTIC COMPOSITION
The invention relates to a flame retardant thermoplastic composition comprising a thermoplastic Eastover and a halogen free flame retardant system and to a mounded part made thereof, more particular to a flexible thermoplastic composition having good flame retarding properties wet-heat resistance and mechanical properties and also more particular to mounded parts selected from mechanical parts, electric and electronic parts, automobiie oarts, and housings and other parts of, for example, office automation apparatuses and. household electronic appliances.
Flame retardant -.thermoplastic composition comprising a thermoplastic elastomer and a halogen free flame retardant system and; moulded parts at least oartly made and consisting thereof, are known from US patent US-5,298,544. US-5,298,544-describes a flame retardant thermoplastic moulding composition consisting essentially of a thermoplastic resin and a flame retardant. The thermoplastic resin is a copoiyetherimide ester or a copolyether ester or a blend thereof. The copolyetherimide ester and the copolyether ester are both thermoplastic.elastomers. The flame retardant is magnesium carbonate or a bienc of magnesium carbonate and saicium carbonate having a combination of zinc Donate or zinc oxide or a blend of zinc borate anc zinc oxide. The Known compositions of US-5,298,544 show flame retardancy properties according to UL-94 standard complying with atypical V2 rating for the copolyethenmiae ester elastomer and VI for the copolyether ester elastomer. For these ratings high leadings of flame retardants of aoout 50 wt.%, relative to the total weight of the moulding composition are used. The said known moulding compositions further comprise a stabilizer package in an amount of about 1 A wt.%, relative tc the total weight of the moulding composition and show eiongation-at-oreak values in tensile test according tc ASTM D638 close to 25%.
A disadvantage of the known compositions of US-5,298,544 is -that in many applications of. moulded parts made of flame retardant thermoplastic compositions, such high loadings and/or iow elongations are not acceptable, whereas in particular cases a V2 or VI rating is insufficient and a V'O rating is required.
The-aim of the invention is tc provide a flame retardant thermoplastic composition comprising a thermoplastic elastomer and a halogen free flame retardant system and a moulded part made thereof, which do not show these disadvantageous or in lesser extent, more particular the invention is aimec at a flame retardam
thermoplastic composition and a moulded part made thereof, which show a V2 rating, and preferably a V1 rating or even a VO rating according to UL-94-V standard at much lower filler loadings, meanwhile having higher elongations than the known compositions. A further requirement is that the compositions should have a good hydrolysis resistance under hot, humid conditions.
This aim has been achieved with the flame retardant thermoplastic composition according to the invention ana the moulded part made thereof, wherein (i) the thermoplastic elastomer comprises a copolyester elastomer comprising (a) hard blocks and soft blocks consisting of segments of hard and soft polyester polymers linked by urethane groups or (b) hard blocks consisting.of segments of a hard polyester polymer and soft blocks consisting of a long chain aiiphatic dicarboxylic acid residue and/or a song chain aliphatic, diol residue, wherein the hard?and: soft blocks are optionally linked oy urethane groups and (ii) the halogen free flame retarcant system comprises a nitrogen containing fiame retardant.
The effect of flame retardant thermoplastic composition according to invention and the moulded pan made thereof, comprising the said copolyester elastomer with (a) hard blocks anc soft blocks consisting of segments of! hard and soft polyester polymers iinKec by urethane groups or with (b) nard blocks consisting of segments of a hare polyester ootymer and soft blocks consisting of a long chain aliphatic dicarbcxyiic acid residue and/or a long chain aiipnatic did residue, and and/or a long chain aiipnatic diol resiaue wnerein the hard and soft blocks are optionally linked oy urethane groups and wnerein the halogen free flame retardant system comprises a nitrogen containing fiame retardant, is that the thermoplastic composition has a flame retardancy performance complying with V2, VI or even VO ratings according to the JL-94-V wnicr ratings are obtained at loadings of the flame retardant system much lower than usee for the flame retardant system in the known composition meanwhile also showing a mucn nigher elongation at break than the known composition of JS-5.298.544 having a. comparable-flame retardancy performance. Surprisingly, the mecnanicai properties of the copolyester elastomer used in the fiame retarcant thermoplastic composition according to the invention is affected only in' iimited extent by the presence of the nitrogen containing flame retardant. in sc far there is such a negative effect, i.e. reduction ;n elongation at creak, or tensile strength, this effect" is certainly limited, whereas in other cases this effect is clearly-positive, exnibited by an increased elongation whiie the Tensile strength at break is maintained at the
same good level. This is even more surprising in view of the fact that nitrogen containing flame retardants, such as meiamine based flame retaraants and in particular melamine cyanurate, are known to negatively affect the mechanical properties in polymer compositions, certainly when used as the only flame retardant and in sufficiently high amounts for obtaining good flame retardancy properties. A further surprising effect is that mechanical properties of the flame retardant thermoplastic composition according to the invention are also retained, after treatment for a longer period under hot, humid conditions, at a level comparable to that of the original copoiyester elastomer with hard PIOCKS anc soft blocks corresponding with the features (a) or (b) as described above.
The-fiame retardant thermoplastic composition according to the invention also; shows better flame retardancy properties than corresponding compositions comprising a copolyether ester elastomer as used in the known composition of US-5,298,544 in combination with nitrogen containing flame retardants, in that either the flame retardancy is better when using the same type and amount of the nitrogen containing flame retaraants ana/or a VO rating is ootainec at lower loadings of the nitrogen containing flame retardants. if such a rating can be obtained at all for the corresponding composition comprising the copolyether ester elastomer. A further difference in favour of flame retardant thermoplastic comoositiori according to the invention is that the mechanical oropenies of the corresponding flame retardant thermoplastic composition comprising the copolyether ester elastomer are certainly affected negatively by the nitrogen containing flame retaraants, exhibited by Sower values for elongation and tensile strength at oreak, which negative effect is already substantially at loading levels far oelow the level at which a VC rating is obtained if any. In further search for alternative flame retardant thermoplastic compositions, aisc other flame retardants have been tested in combination with tne coooiyether aster elastomer as used in the known composition. Among these other flame retaraants, a flame retardant system comprising aluminium diethylphcsphinate was found to be aoie to provide a solid VO-rating. For obtaining a solid VC, much higher loadings of the alternative flame retardant system was requirec than needec for the nitrogen containing flame retardants in the inventive compositions. Moreover, the said aluminium diethylphosphmate based flame retardant system nas a significant negative effect on the mechanical properties o; the copolyether ester aiastcmer. resulting in significantly lower values for both the elongation at break and iensiie strength compared, to-'the corresponding copolyether ester elastomer.

Flame retardant thermoplastic composition comprising a thermoplastic elastomer and/or a halogen free flame retardant system comprising one or more-of the features of the compositions according to the invention have been described in different patents or patent appiications, as described below. None of these patents describe the inventive compositions or the effects thereof as according to the invention.
EP-0102115-B1 describes polyester ester biock-copolymers with low melting soft blocks and high melting hard blocks composed of polyesters- and linked by urethane linkages, as may also be used in the flame retardant thermoplastic composition aceording to the invention. EP-0102115-B1 does not describe any flame retardant compositions based on the said polyester ester block-copolyrn$rs, let alone the flame retardancy or mechanical properties thereof.
EP-0363321-B1 describes a flame retardant thermoplastic composition comprising melamine based flame retardants as halogen free flame retardant system. The meiamine based flame retardants consisted of melamine salts of phasphonic acids, which were typically tc be used in an amount of 1-100 pbw (parts by weight) relative; to 100 pbw of a-thermoplastic polymer. For the possible polymers that cart be useda&rttoe thermoplastic polymer many polymers are mentioned, including block-CQpoiijtettjeFesters, which as said above are thermoplastic elastomers. Various examples ate described in EP-0363321-B1 with flame retardancy test results showing different ratings. Only few examples, based on epcxy based poiyetber poiyurethane showed a V-0 rating. The mechanical croperties of those examples were not mentioned. However, none of the examples included a copolyetherester as mentioned in the above cited prior art, let alone copoiyester as used in the compositions according to the invention or the effect thereof.
Flame retardant thermoplastic moulding compositions are also described in EP-037S237-A1. EP-0376237-A1 further describes moulded products made from the flame retardant thermoplastic moulding compositions, more particular "Kabelbinder" and Steckerieisten". The Known flame retardant thermoplastic moulding compositions of EP-037S237-A1 consist of a thermoplastic oolyamide (A), a thermoplastic polyetherester elastomer (B), meiamine cyanurate (C), and a filler. The amount of (B), only 0.45-15 wt.%, as well as the amount of (C), only 0.05-1,98 wt.%, both relative to the total of (A), ,'B) and ;C;, are very low. Meiamine cyanurate is a nitrogen containing-flame retardant. EP-0375237-A* explicitly states that the use of melamine cyanurate is problematic and wnen the amount oecomes too large: ;t
influences the mechanical properties.
EP-Q868478-B1 describes flame retardant elastomer compositions comprising a thermoplastic elastomer and one or more nitrogen containing flame retardants. The known flame retardant eiastomer compositions of EP-0S68478-81 are used for construction sheetings and have to comply with flame retardancy standards from the building industry (DIN 4102 B2). The nitrogen containing flame retardants are melamine condensates and melamine compounds, which are used in an amount of 5 to 30 wt.% based on the thermoplastic elastomer. Dreferred compounds are melamine cyanurate and meiam. The thermoplastic elastomer is chosen from the.group consisting of polyurethane block copolymers, polyetheramide oiock copolymers, polyefrrefestefr block copolymers and polyester ester biockcapolymers. The examples in EP-Q868478-B1 are with polyurethane block copolymers, poiyetheramide block copolymers, and poiyetherester block copolymers. Polyetherester block copolymers are preferred. None of the examples is with a polyester ester blockcopoJymer. Also no test results secorcMng to the UL-94-V standard are mentioned in EP-08B8478-B1. whereas DIN 4102 B2 is certainly not aiike and likewise much less critical than UL-94-V. Although:some of the copoiyester elastomers in the composition according tc the invention can be considered to be or are copoiyester elastomers, neither copoiyester elastomers-.as used in the composition according tc the invention, nor the advantageous effects thereof, are mentioned in EP-0868478-B1. Apart from construction sheetings nc other possible applications are mentioned.
Thermoplastic copoiyester elastomers with hard blocks anc soft blocks linked by urethane linkages are describee in EP-0846712-81. The hare blocks in the copoiyester elastomers of EP-0846712-B1 are composed of poifyesters, whereas the soft blocks are composed of segments of a low melting aliphatic polycarbonate polymer. Reported possible applications of the block copolymers include pipes, hoses, cable and sheets, and in particular bellows and seals for automotive applications. The said block copolymers can be made flame retardant with flame retardants preferably melamine cyanurate. No amounts of flame retardants are mentioned and mechanical and flame retardancy properties of the flame retardant elastomers are not are not described in EP-0846712-B1.
The copoiyester elastomer in the flame retardant thermoplastic composition according tc the invention comprises hare olocks consisting of segments of a. hard polyester polymer, also denoted herein as hard polyester poiymer segments.. Next to that the copoiyester eiastomer comprises soft biocKs consisting of segments of
a soft polyester polymer, also denoted herein as soft polyester polymer segments, and/or soft olocks consisting of a long chain aliphatic dicarboxylic acid residue and/or a long chain aliphatic diol residue, herein denoted together also as soft aliphatic segment. The soft polyester polymer segments are iinked to the hard polyester polymer segments oy urethane linkages. The soft aliphatic segments' are iinked to the hard polyester polymer segments by ester, amide and/or urethane linkages, Ester linkages can be formed by reacting a long chain aliDhatic diol with a carboxyl functional polyester, or by reaction a long chain aliphatic diacid with a hydroxyl functional polyester. Amide linkages can be formed by reacting a long chain aliphatic diamine with a hydroxyl functional polyester. Urethane linkages can De formed by reacting a iong chain aliphatic diol with an isocyanate modified polyester, or by reaction a hydroxyl functional polyester with an isocyanate modified long chain aliphatic diol.
Copolyester elastomer comprising, soft polyester polymer segments linked to the hard polyester polymer segments by urethane linkages ares generally considered as:being part of the group of copolyester ester elastomers. Such copoiyester ester elastomers can be made by letting react a low melting aliphatic polyester prepoiymer dioi and a high melting, aromatic, prepoiymer diol with di-isocyanate or by reaction an isocyanate capped prepoiymer with a prepoiymer dioi. For the isocyanate-capped: prepoiymer one can choose to: either- cap the low melting aliphatic polyester prepoiymer diol or high melting aromatic prepoiymer dioi with a di-isocyanate and than to let it react with the other dioi. Other members of the group of copoiyester ester elastomers include copoiyester elastomer comprising :soft polyester polymer segments iinkec to the hard ooiyester polymer segments by ester linkages. These latter copolyester ester elastomers can be made by separately preparing a low melting aliphatic polyester prepoiymer and a high melting aromatic prepoiymer, one of these prepolymers being a dioi and the other being a dicarboxylic acid, and then mixing the two ootymers and. an esterification catalyst at elevated temperature-in the melt under nitrogen. Once a transparent mixture is obtained, the esterification catalyst used in the orocess. must be deactivated.
Such copolyester ester elastomers-with aster linkages are not suited for making flame retardant compositions with nitrogen containing flame retardants in that such compositions perform less good in one or more of the properties in which the flame retardant compositions excel, i.e. flame retardancy, good retention of eiastomeric properties upon addition of the nitrogen containing flame retardants as well as retention thereof after treatment under hot humic conditions
The copoiyester elastomers with soft iong chain aliphatic segments linked to the hard polyester polymer segments by urethane and/or ester linkages, can be prepared in the same way as described above for the copoiyester ester elastomers with either urethane or ester iinkages, except that in stead of a soft polyester prepolymer dioi or soft polyester prepoiymer dicarboxylic acid a soft long chain aliphatic diol or diacid is used, and combined with, as suitable, with a polyester prepolymer dioi, diacid or isocyanate end-capped.
The flame retardant thermoplastic composition according to the invention comprises a copoiyester elastomer comprising (a) nard blocks and soft blocks consisting of segments of hard and soft polyester polymers linked by urethane groups a&dfm (b) haed blocks consisting of segments.of a hare polyester polymer and soft blocks consisting of a iong chain alipnatic dicarboxylic acid residue and/or a iong chain aliphatic, diol residue, wherein the hard and soft blocks are optionally linked by urethane groups and (ii) the halogen free flame retardant system comprises a meJamine based flame retardant.
The polyester polymer segments ;n the nard stocks suitably consists of repeating units derived from at least one alkylene dioi and at teast one aromatic or cycioaiiphaticdicarboxyiic acid.
The: aromatic dicarboxylic acid in these polyester segments suitably is selected from-the group consisting of terephthaiic acid, isophthaiic acid, phthaiic acid, 2.6-naphthatenedicarbaxyiic acic and 4.4-djphenyldicarDoxyiic acid, and mixtures thereof.
Preferably, the aromatic dicarboxylic acid comprises terephthaiic acid, more preferably consists for at least 5C mole %, still mere preferably at least 90 mole %, or even fuily consists of terephthaiic acid, relative tc the totai molar amount of dicarbaxyiic acid in the hard polyester polymer segments.
The alkylene diol ir. the hard polyester segments preferably is a dioi with 2-15, and particularly with 5-10 carbon atoms. The alkylene diol suitably is selected from the group consisting of ethylene glycol, oropyiene glycol, butyiene glycol, 1,2-hexane diol, 1,5-nexamethyiene dioi, 1,4-outane diol. benzene dimethanol. cyclonexane diol, cyclohexane dimethanoi. and mixtures thereof. Preferably, the aikylene diol comprises ethylene glycol and/or 1,4-butane diol, more preferably . consists for at least 50 moie %, still more preferably at least 3C mole %, or even fully consists of ethylene glycol and/or l.-i-outane dioi, relative to the total molar amount of alkylene diol in the polyester oclymer segments
In a preferred embodiment of the invention the polyester polymer segments in the hard blocks consist for at least 90 mole %, relative to the total molar amount of dicarboxyiic acid and alkyiene diol in the hard blocks, of repeating units derived from 1,4-butane diol and terephthalic acid.
The poiyester polymer segments in the soft blocks suitably consists of repeating units derived from at least one alkyiene dioi and at least one aliphatic dicarboxyiic acids, and/or from at ieast one lactone and/or hydroxy! functional aiiphatic carboxyiic acid.
Suitable aliphatic diols include ethylene glycol, 1,4-butanedioi, 1,5-pentanediol, 1,6-ftexanediol, 2,2-dimethyM,3-propanedioi, and mixtures thereof. Also other glycols, such as 1,3- or 1,4-cyclohexanediol or i ,3- or ' ,4-bis(hydroxymethyl)-cyc!ohexane, may be incorporated into the ;ow melting components. Under some circumstances, for instance to increase the melt viscosity of the endrproduct, it may be recommenaed to incorporate some small amount of higher functional compounds. Examples of such compounds are trimethylol ethane, trimethyiol propane and hexane trioi.
Preferably, the aiiphatic dioi in the soft poiyester polymer segments comprises T,4-butarTedioi, 1,5-pentanedioi, 'S-hexanedioi. 2,2-aimethyt-1,3-prapanediol and-mixtures thereof in an amount of at ieast 5C mole %, still more preferably at least 70 mole %, or even more preferably at least 90 mole%, relative to the total moiar amount of aliphatic dioi in the soft poiyester polymer segments, or even consists for 100 % of the said aiiphatic diois.
Suitable aliphatic dicarooxylic acias are, for example, adipic acid, glutaric acid, pwneiic acid, suberic acid, isoseoacic acid and ncinoleic acid. Aiso aiiphatic dicarboxyiic acids having hetero atoms, such as thiodipropionic acid may be used in the low melting afunctional compounds, in addition there still may be mentioned oydcaliphatie dicarooxylic acids such as i ,3- ori ^.-cyclohexane dicarboxyiic acid and: terephthalic acid and isophtnalic acic, wnich may be ccmonsed in the soft polyester segments in small amounts.
Preferably, the dicarboxyiic acid in the soft poiyester polymer segments compnses adipic acid, more preferably consists for at least 50 mole %, still more preferably at least 70 mote %, or even at ieast 90 mole%, relative to the total molar amount of dicarboxyiic acid in the soft poiyester polymer segments, or even consists for 100 % of adipic acid.
Other than being compcsec of trie reaction products of short-to-
medium-long chain aliphatic diols and aliphatic dicarboxylic acids, the low melting soft blocks may as well entirely or partly be composed of lactones, such as substituted and unsubstituted caprolactone or butyrolactone.
The procedure for preparing the iow melting oolyesters is known per se and similar to that used for preparing high melting polyesters. It may be realized for instance by pdiycondensation of polyfunctional, preferably Afunctional alcohols, hydroxycarbaxylic acids, and lactones. By a proper choice of the mixing ratio of the above-mentioned components any desirable molecular weight and number and type of terminal groups may be obtained.
The long chain aliphatic diol from which the soft segments may be derived* may le-any aiiphatic polymer terminated with nydroxyl groups. Suitably, the. long- chain aiiphatic diol is a.polyene diol. for example a polybutadiene diol or a hydrogenatediderivative thereof.
Suitably, the long chain aliphatic diol has a molecular weight varying over a large range, and which molecular weight may be as low as. 400, or even lower, and as high as-2000., or even higher. Preferably long chain aliphatic diol has a moiecular weight in the range of 500 -1.200, more preferably 800-1200. A higher molecular weight has the advantage that the eiastomeric properties are further enhanced.
The long chain aliphatic diol, more specifically the residues thereof can be present in the copoiyester elastomer in an amount varying over a large range, and preferably in a range of 30 - 70 wt.%, preferably 4C-65'wt.'%, more;preferably 50-6Gwt.%, reiattvetQ the weight of the copoiyester eiastomer. Where the-long chain aliphatic diol can be represented by the formula HC-R-OH, the residue thereof is represented by the formula f-O-R-O-j, which latter formula ;s used for the calculation of the amount.
The long chain aiiphatic diamine, from which the soft segments may be derived; may.be any aiiphatic diamine which is aole to phase separate from the hard block polyester segments, thus providing the copoiyester elastomer with eiastomeric properties. Suitably, the long chain aliphatic diamine is a compound corresponding with the lomg; chain aiiphatic dioi, and preferred embodiments thereof, described above, wherein the terminal hydroxyl groups have beer, replaced by primary anine groups.
The long chain aiiphatic diacid from wnich the soft segments may be derived, may be any aliphatic diacid which is able tc phase separate from the hard biock polyester segments, thus providing the copoiyester elastomer with eiastomeric
properties. Suitably, the long chain aliphatic diacid has a moiecuiar weight varying over a large range, and which moiecuiar weight may De as low as 400, or even lower, and as high as 1QQG, or even higher, Preferably long cnain aliphatic diacid has a molecular weight in the; range of 500 -800, more preferably 550-700. A higher moiecuiar weight has the advantage that phase separation is improveG and elastomeric properties are enhanced.
The long chain aliphatic diacid, more specifically the residues thereof can be present in the copoiyester elastomer in an amount varying, over a large range, and,preferably in a range of 30 - 70. wt.%, preferably 40-65 wt.%, more preferably 50-60wt.%, reiatiseto the weight of the copoiyester elastomer. Where the long chain aiptetiedJ2W^cafT&ei:re|jreserTted by the formula HO(-0)C-R-C(0)OM, tfce- residue-themof is represented-by the formula [-0(C)-R-(C)0-3, which latter formuja is used for the calculation of the amount.
Examples of suitable long chain aliphatic diacid are compounds known as diner fatty acids, for example derived from oleic and iinoleic acids. The long chain aiiphafediaeids may suitably be linear or brancheo. Dimer fatty acids, are available^ farsSKafnpie;, under trade name Pnpoi from Uniqema, The Netherlands.
The ucethane linkages in the polyester elastomer suitably consists of refseating;uwlf-derivedfram atieast one aliphatic or aBcyciic diisocyanate and/or-at least ®ne aiDEta-icdiisacyanate. The urethane linkages can be represented by the formula [-(Q)&(H)'f4-R--N(H}-C(0}-], wherein R is an aliphatic group, an aiicyclic or an aromatic group;, which groups can optionally be heteroatom substituted.
Examples of suitable atipnatic diisocyanates are nexamethylene diisocyanate, dimethyl hexamethylene diisocyanate. trimethyi nexamethylene dttsecyanafe, metaMy4ytene diisocyanate, paraxylylene diisocyanate, tetfamethyiene dnsocy-aKjale:' Suifeabie diisocyanates having an aiicyclic group include isophoron diisocyarralSi dicyclohexytmethane diisocyanate ana 1 4-cyclohexane diisocyanate. Examples of suitable;aromatic diisocyanates include: 1 -cnioro-2,4~pnenylene diisocyanate, 2,4-toiuene diisocyanate, ietramethylpherryiene diisocyanate, dipheny4methane-4;4'-diisocyanate (MDl), metaphenyiene diisocyanate, paraphenyiene diisocyanate, naphthalene-1,5-diisocyanate, diphenyM ,4'-diisocyanate,\ phenyimethaBe^4,4'-o3isocyanate, bipnenyldirnethylrrtethane-4,4'~diisocyanate, benzophenone-4,4'-diisocyanate, oipnenyietner diisocyanate and bipnanyisulpmde diisQcyanate,-ar3,-dicneth.yldipheny!-4,4'-diisocyanatev S.S'-dimetnoxydiphenyM^'-diisocya^ate■, 3,3'-d.ichiarod!pbenyi-^,4'~diisocyanate, 2.3'-dicnlorodiphenyi-4 4!-
diisocyanate, benzofuran-2,7-diisocyanate.
Preferably, the diisocyanate from the urethane linkages are derived compriae djphenylroetb.ane--4,4'-diisocyanate (MDI), more preferably in an amount of at least 50 mole %, still more preferably at least 70 mole■%, or even at least 90 moie%, relative to the total molar amount of diisocyanate in the soft polyester polymer segments, or even consists for 100 % of diphenylmethane-4,4'-diisocyanate MDI.
The copolyester elastomer in the flame retardant composition according to tee invention preferably comprises hard and soft segments linked by urethane linkages, more preferably the soft segments comprise or even consist of segments of a soft polyester polymer. The effect of the urethane linkages is that the performance of the compositions in the UL-94-V flame retardancy test i£ improved, and the minimum amount of melarnine based flame retardants needed for obtaining a V0 rating is reduced.while better mechanical properties, more particular a higher elongation-at-break is obtained. These effects are further enhanced with the soft segment comprise segments of a soft polyester polymer.
Stilt more preferably, the urethane linkages are present in the copolyester elastomer m an amount in the range of 1-15 wt.%, relative to the total weight of theicapolyester elastomer, and wherein the weight of the urefiiane linkages based orr structural elements represented by the formula !-(Q)C-{H)N-R-N{H}-C(QH
Copolyester elastomers comprising hard and soft polyester segments. linked by urethane linkages, as well as the synthesis, thereof, are described in EP-0:1X12115-61, which patent forms an mtegrai part of this invention by reference.
In a preferred embodiment of the invention, the hard blocks of copolyester elastomer have a melting point (Tm) of at least 150°C, preferably at least 165 °C, 180'°C, 20Q.°C or even at least 22Q°C and the soft blocks have.a glass transition temperature'(Tg) of at most 2C°C. preferably at most 0°C. -20°C, -40°C: or even atmast-5Q°C, The. advantage of the copolyester elastomer having the said minimum Tm is. that it has better mechanical strength and better retention of the elongation upon treatment: with hot numid conditions, whereas a lower maximum Tg leads to mare flexible products with higher elongation.
With the term melting point (temperature) is herein 'understood the temperature: measured by DSC with a heating rate of 1C°C/min falling, in the melting temperature range and showing the highest melting rate. With the term glass transition point is herein understood the temperature measured by CSC with a heating rate of
10°C/min falling in the glass transition temperature range and snowing the highest glass transition rate.
in another preferred embodiment of the invention, the flame retardant thermoplastic composition has a hardness between 20 and 70 Shore D, preferably between 30 and SO, still more preferably 40 and. 50 Shore D.
Next to the copoiyester elastomer, the flame retardant thermoplastic composition may comprise other thermoplastic polymer elastomers, such as polyetherester elastomers and polyetheramide elastomers, as well as other polymers, such polyesters, palyamides and polycarbonates. If any polymers other than the copoiyester elastomer are present, thermoplastic polymer elastomers are preferred.
Preferably, tfte flame retardant thermoplastic composition- comprises the said copoiyester elastomer in an amount of at least 50 wt.%, more preferably at ieast 75vwt.%, 90 wt.% or even at least 95 wt.%, relative to the total weigtst of polymer in the^ffame-retardant thermoplastic composition. The effect of the higher copoiyester elastomer content is that the effect of the invention is further enhanced.
Suitable nitrogen containing flame retardants, that can be usee in the flame retarded thermoplastic composition according to,the invention a re,, for example, flame, retardants based on triazines, guanidines, cyanurates, and isoc.ya$uraiesr and mixtures, and salts thereof. Suitable triazine based flame retardants are, for example, meiamine bassd.flame retardants, which include melamine, melamine condensation products, melamine cyanurate and melamine salts, and comDinations thereof.
Suitable melamine condensation products are for example melam, melem, and'melort, and:higher condensation proaucts of meiamine. These condensation' products generally comprise mixtures of differeni oligomers of meiamine. As a. major component, melam, melem. and melon comprise respectively dimers, trimers and tettamers of melamine. Meiamine condensation products cars, for example, be obtained? with the process described in WC-A-96/16948. Suitable salts: of the nitrogen containing flame retardants are. for example, borates and oxalates, and salts of phosphor containing compounds, such as phosphates, phospinates and: phosphorates and aligomoric and polymeric derivatives thereof. Examples of suitable nitrogen and phosphor containing compounds are ammonium polyphosphate and melamine polyphosphate.
Preferably the nitrogen containing flame retardant is a melamine based flame' retardant. The advantage thereof is that better flame retardancy properties are obtained as measured according to 'JL-B^-v standard ai the same or
lower loadings, and that higher elongations are obtained at loadings with comparable flame retardancy performance according to JL-94-V.
Suitable melamine based flame retardants include meiamine, melamine condensation products, melamine cyanurate and melamine salts, and combinations thereof. Examples of melamine salts include melamine (poly)phosphates, e.g. available under the trade name Melapur20C from Ciba Geigy, melamine borates and melamine oxalates.
Mora preferably, the meiamme oased flame retardant comprises a melamine condensation product and/or melamine cyanurate, more preferably melamine cyanurate. The advantage of melamine cyanurate is that it provides an even that betSerfiatne retardancy properties are obtained at the same or iower loadings, and/or that elongations are better retained upon treatment under hot numid conditions.
Melamine cyanurate is the reaction product of preferably equimolar amounts of melamine and cyanunc acid or isocyanuric acid. It can be made by conversion of aqueous solutions of the starting compounds at 90 to 10®°C. Melamine cyanurate is commercially available as a white product with a particle size distribution wherein the. particle size can van' over a iarge range, generally in the range of 0.1-100 pm. The me^ttnine cyanurate -'that is used is preferable of small particle size, or can be easily dtepeiraped" into small particles in a polyester continuous phase during mixing, Suitably, the melamine cyanurate has a particle size distribution with a median particle size (d50) smaller than about 25 micrometer (urn- and larger than 0.5 um; preferably the mediae, particle size d 50 is in the range of 1-15 urn, more preferably in the range of 2-10 um. Very suitably, the median particle size d50 is in the range of 2.5-5 um.
With the median particle size d50 is herein understood the particle size, relative? to which 50 wt.% of the: particles have a smaller particle size and 50 wt.% of the particles a larger particle, This, median particle size can be determined as D50 according to ASTM standard D1321-89, method A.
The nitrogen containing flame retardant may oe present In tne flame retardant thermoplastic composition according to the invention in an amount varying over a wide range, which amount may De as low as 7.5 wt.% or jower and also as high as 40 wt.% and-higher. Preferably, tne niirogen containing flame retardant is present in an amount between 7.5 and 40 wt.%, anc more preferably in the range of 10-35 wt.%, still more preferably 15-25 wt.%. Herein tne weignt perceniage (wt.%) of the nitrogen containing flame retardant is relative to the total weight of the flame retardant thermoplastic composition, ^he advantage of a higher minimum amount is that better
flame retardant properties are obtained, whereas with a lower maximum amount better mechanical properties are obtained
The flame retardant thermoplastic composition according to the invention may comprise, next to the nitrogen containing flame retardant, other flame retardant compounds or flame retardant synergists to further enhance the: flame retaedant prope#es of tire thermoplastic composition. For these other flame retardant compounds and flame retardant synergists, together indicated as other flame retardant components, any flame retardant compound suitable for use in thermoplastic elastomers or any ffame retardant synergist suitable for use in combination with nitrogen containing flame retardants may be used. Preferably these otherflame retardantcomp&nentsr are nalogen free. Preferably, these other flame*retBrd&nt components, are-used in such an amount that the mechanical properties, in particular the elongation and/or the retention thereof upon treatment under hot humid conditions are not affected or oniy so in limited extent. Suitable types and amounts of these other flame retardant components can be determined by theperson skilled in ttreart of making flame retardant thermoplastic composition by routine experiments and testing.
A flame retaedant.synergist is herein understood: to be s. compound thai further improves the.flame retardant properties of the inventive polyester composition, S&itebiy, the flame retaraant synergist is an inorganic compound such as talc, arnetat oxide-, a metal sulphide or a meta! borate. An example of a suitable metal borate is zinc., borate.
Preferably, the other flame retardant components, if present at ail, are present in arramount of 0.01 -TO wt.%. more preferaoly 0.1-5wt.%, still more preferably 0.2-2 wt.%, refetive to. the totai weight of the thermoplastic composition. Most preferably thesamount is 0 wt.% i.e. there are nc other flame retardant components present.
In addition to the constituents mentioned here above, i.e. the polymeric components-" and the flame retardant system, the flame retarded thermoplastiecamposition according to the invention may further campfrse one or more auxiliary addilives, such as fillers, reinforcing agents, stabilizers, processing aids, colouring agemts
The fillers, reinforcing agents and other auxiliary additives that can be used in the flame retarded polyester composition may be any such compound G«waafeatsra% used inflame retardant. thermoplastic compositions.
Fillers and reinforcinc agents generally consist of inoraanic fibrous
materials and powder consisting of small particles, typically with a particle size beiow 1mm, preferably below 0.1 mm, more preferably below 10 urn. Suitable examples of fillers are magnesium carbonate, kaolin, quartz, calcium carbonate. Suitable reinforcing agents include-glass fibers and carbon fibres. The fillers and reinforcingvagents are suitably used in a total amount of up to and even exceeding 50 wt.% of the total composition. Preferably, fillers and reinforcing, agents are present in a total amount of 0-50 wt.%, more preferably 0,01-30 wt.%, or 0.1-20 wt.%, and most preferably 1-10 wt.%, relative to the total weight of the flame retardant thermoplastic composition.
The-other auxiliary additives are suitably present in a total amount of 0-20 wt.%, more preferably 0,01-10 wt.%, or 0.1-5 wt.%, and most.preferably 1-3 wt.%, relative to the,.totai weight of the flame retardant thermoplastic composition
Suitable stabilizers include, for example, trans-esterifieation inhibitors, UV-stabilizera-, heat stabilizers ana anti-oxidants, as well as combined thermo-oxidative stabilizers. Additives- suitable as heat stabilizer and/or and anti-oxidant are, for example, hincjered phenols, hydrochinones. Suitable UV-stabilisers are, for example, benzophenone. benzotriazoles, resorcinois, anc saiyciiates. Stabilizers are suitably present in a total amount of 0-5 wt.%, preferably O.OT-3 wt.%. or Q.05-2wt.%. and. most preferably 0.T-1 wt.%, relative to the totar weight of the flame retardant thermoplastic cam position.
Suitable processing aias include mould release agentte, such as fatty acids and derivatives thereof, including: stearic acid, stearic alcohol and stearic amides, lubricants or viscosity reducers, and nucleating agents, such as talcum. These adsditives aresuitabiy used in a totai amount of 0-3 wt.%, preferably 0.0*1-2 wt.%. more preferably 0.1-1-wt.%, relative tc the total weight of the flame retardant thermoplastic composition.
Suitable colouring agents include pigments, such as Itanium dioxide: aod carbon biaste, and dies, such as nigrosine. Colouring agents are afeo are suitably used in attjfiaiatnount-of 0-3 wt.%, preferably 0.01-2 wt.%, more preferably 0.1-1 wt.%; relative to ftmtotal weight of the flame retardant thermoplastic composition.
In a specific embodiment of the invention, the flame retarded thermoplastecompositian is. a halogen free1 flame retarded thermoplastic composition, consisting; of
A) a copolyester elastomer as according to claim 1 of the invention, and optionally
B) one or more other polymeric components, wherein (A) is present in a amount of ai least 50 wt.% relative tc the total weight of (A) and (B),
C) between 7.5 and 40 wt.% of a nitrogen containing flame retardant as according to claim 1 of the invention, and
D) 0-10 wt.% of one or more other halogen free flame retardant components,
E) 0-50 wt% of one or more fillers and reinforcing agents, and
F) 0-20 wt.%. of one or more other auxiliary additives,
wherein the weight percentages of (C), (D), (E) and (F) are relative to the'total weight of the flame retKderi thermoplastic composition, and wherein the sum of (A)-(F) is 100 %.
In a- preferred embodiment of the invention, the flame retarded thermoplastic composition is a halogen free flame retarded thermoplasticcomposition, consisting of A). a, copBifsester elastomer comprising hard blocks and soft blocks consisting of
segments of hardJand soft polyester polymers iinked by urethane groups, and
optionally B); one or more other polymeric components, wherein (A) is present m a* amount of
at least50. wt.% relative to the total weight of (A) and. (B), Q; betweerr7.5and 40 wt.% of a meiamine oased;flarne retardant, and D): 0-1G wt.% of one or more other nitrogen containing free flame retardants and/or
other halogen free flame retardant components,
E) 0-20 wt.% of one or more fillers and reinforcing.-agents, and
F) 0-10 wt% of one or more other auxiliary additives,
wherein the weight percentages of (C), (D), (E) and (F) are relative, to toe total weight of the flame retarded thermoplastic composition, and wherein the sum of (A)-(F) is 100 %.
in a-rosre preferred embodiment of the invention, the flame-retarded thermoplastic: composition is a halogen free flame retarded thermoplastic composition, consisting of A) a?CQpc3%ester elasfomer comprising hard blocks and soft blocks consisting of
segmewtsvof hard and soft polyester polymers iinked Dy urethane groups, and
optionally B)' other polymeric components, wherein (A) is present in a amount of at least 50
w£.% Native to, the-total weight of (A) and (B), C) 15-35 wt.% meiamine cyanurate, and
D) 0-5 wt.% of one or more other meiamine based flame retardant and/or other
nitrogen containing flame retardant and/or other halogen free flame retardant
components,
E) Q-1CTwt.% of one or more fillers and reinforcing agents, and
F) 0-5 wt.% of one or more other auxiliary additives,
wherein teeweight percentages of (C), (D), (E) and (F) are relative to the total weight of the flame retarded thermoplastic composition, and wherein the sum of (A)-(F). is TOO %.
The copolyester elastomers used in the flame retarded thermoplastic composition according to the invention, as well as these inventive compositions and awy-ppeS&FresteerafacdJFnemts.-thereof, can be made using conventional methods. The preparation of copolyester elastomers comprising hard blocks and soft blocks consisting of segments of hard and soft polyester polymers linked by urethane groups, is described; tor example in EP-Q102115-B1. For the preparation of the flame retarded thermoplastic composition, one can suitably use melt-mixing equipment, such as single screw extractors, double-screw extruders, Brabender mixers and Banburry kneaders.
The inventive compositions are very suited for making moulaed parts by, means of'ssanous moulding techniques, including injection moulding and extrusion moulding and over moulding, in particular for the preparation of fiexibleimqulded'parts far various; high demanding technical applications. For these applications, the good fiame retafidancy properties in combination with the high elasticity and retention of mechanical properties upon treatment under hot humid conditions are very advantageous.
The invention therefore also relates to the use of the flame retardant thermoplastic composition according to the invention in a moulding process for making am injection moulded part, an extrusion moulded part or an avermoulded. part.
The invention also relates to a shaping process for making a moulded pan comprising, a step wherein the moulded part is shaped by injections moulding, or extrusion moulding of an elastomer composition according tc the invention, or any preferred erBtoadiment thereof, or overmoulding of an elastomer composition according. to the invenifcin, or any preferred, embodiment thereof over a core part.
The invention also relates to a moulded part at least' partly made from a ffame-retardant thermoplastic elastomer composition according to the invention, or any preferred; embodiment thereof, oreferably being a an injection moulded part, an extrusion moulded, part or an over-mouloed part.
In one preferred embodiment, the moulded part is an over- moulded part comprising, a core part over-moulded with a layer of the flame retardant thermoplastic elastomer composition according to the invention, e.g. PC/ABS structures avewnQulded with the flame retardant thermoplastic elastomer, electrical cable sheeting, multilayer hoses.
In another preferred embodiment, the moulded part is an extrusion moulded past selected from the group consisting of monofilaments, e.g. for suspension seatings, eiecteical cafale sheeting, for example insulating layers and/or jacket layers, hoses, tubes, &g, convoluted tubes, air brake tubes, air ducts, and fuel tubes, seaiings, such as sounds:deadening profiles for window sealing, and alike.
Frr a?farther preferred embodiment, the moulded part is an injection moulded part selected; from the group consisting of shoe ware, mechanical parts such as cable ties, wtotational and noise dampeners, electrical and electronic parts, e.g. connectors, aiiDwrabile parts, e.g. inboard boots and joint velocity boots (or jvc-boots), engine part,.eig. km noise gears, parts of and housing-for office automation apparatuses anelectrical household appliances, and parts for use in public transport such as boats,.busses, trains and airplanes.
The moulded part according to the invention preferably, is a Met-Shaped-fait'at" least-partly made-from-and-conststing-of one or more flame retarding theran aplastic compositions according to the invention.
With the term "Net-Shaped-Part" is herein understood a three dimensional fReesfanding structure explicitly not being a flat part or a sheet. With the term "at least partly made-from-and-consisting-of' is herein understood that the Net-Sftaped^Paft may have been made only from the said flame retardant thermoplastic compasMafT .awd;consequently will consist integrally of the said flame retardant thermoplastic:composition, or that one or more pans of the Net-Shapect-Part may have been made from the said flame retardant thermoplastic composition and consequently will?coftsistiolfthasaidflame retardant thermoplastic composition, whereas one or more other parts oithelfet-Snaped-Part may have been made from another composition or other com positions, which other composition or compositions may optionally have been blended wtfrttr© said flame retardant thermoplastic composition, and consequently these oneor 'mere other partswill consist of the said other composition; or compositions optionally blended with the said flame retardant thermoplastic composition.
The invention is further illustrated with the following, examples and comparative experiments.
Materials
TPE-E-1 Polyetherester elastomer comprising hard segments consisting of
polybutyleneterephthalate segments and soft segments consisting of EQ/PQ- poiyether blockcopolymer: hardness Shore-D 36.
TPE-E-2 Poiyetherester elastomer comprising hard segments Consisting of
pal^au^eneterephthalate segments and soft segments consisting of FTMG poiyether soft segments; hardness Shore D40
TPE-E-3 Polyasterester consisting, of hard segments consisting of
palytotyleneterephthalate segments and soft segments consisting of paiytactone segments linked with urethane groups; haadness Shore D55„
TPE-E-4 Polycarbonate ester elastomer consisting of
paijstbM^ieneterephthalate hard segments and soft segments consisting of polycarbonate soft segments linked with iFethane groups.
Mecy: Melamine cyanurate (MC50; particle size distribution with a d50 of
aoout 4.2 ^m and a d98 of about 45 urn)
Exolii 1312: Bienctaf aiummium diethylphosphinate, melamine pol and Zinc Borate Clariant
Moulding compositions of Examples i-Vi (EX-1 - EX-V! J according to the invention, and Comparative Experiments. A-L (CE-A - CE-L) were prfpated and tested as descritJeri below. The compositions and test results are--presented in Tables 1 and 2.
CompoundirTq-
For the preparations of moulding compositions, ingredients were coin pounded m ratios, as indicated in Table 1. The moulding compositioits, were prepared- by raeH^blencting. the T*PE-E'S with the flame retardant compofiefits and stabilizer pactaagpon aZSK 30/33 twin-screw extruder with screw speextZQO rpfrt, throughput TfJkgmr, and melt temperature regulated at 250°C, extruding tte melt from the extruder tttrougtr a> die-, and cooling and granulatisg the melt The giiprwles obtained by compounding' in the extruder were dried for 24 nours at 120°C, prior to further use.21
Moulding of test samples
Test samples for Testing the mechanical properties and theflame retarda-ncy- properties were prepared on an injection-moulding, machine: of typfiEngel 80 A. For the injection moulding set temperatures of 235*-245°C were used. The mould temperature was 90°C. Cycle times for the test specimens were about 50 sec.
Test methods
Mechanical properties: Tensile tests were performed according to ISO 527/1A using dry-as-mouldec samples. Dimensions of tensile test specimens: thickness 4 mm.
Flame retardancy: Sample preparation and testing was performed according to UL-94-V standard, with lest specimens hawing a thic'Kness of 1.6 mm.
Hydrolysis resistance: for this test thersampie cable is kept in a. temperature cyeiing chamber for 95 hours at S5°C and 95% relative humidity. After this conditioning, the mechanical properties of the test specimens were tested as described above.
Compounds with the oompositions ofExamDies -V! (EX-i - EX-V!) according to the invention anc: Comparative Experiments A-L (CE-A - CE-L) were prepared: and tested-as describee above. The compositions anc test results- are presented in Tables 1 and 2.

(Table remove)

TfNf f: e>empq§itjpns On p§rts by weight) and test results for Comparative Experiments D-L

CLAIMS
Flame retardant thermoplastic composition comprising, polymer comprising a them?epJastic elastomer and a halogen free fiame retardant system characterized in that
(i) the thermoplastic elastomer comprises a copoiyester elastomer comprising (a) hard blocks consisting of segments of hard polyester polymers and soft blocks, consisting soft polyester polymers linked by urethane- groups and/or (b} hard blocks consisting of segments of a hard polyester polymer and soft blocks consisting of a long chain aliphatic djcarhoxyiic acid residue, a. long chain aliphatic amine and/or a ions chain aliphatic dial residue, wherein the hard and’ soft blocks are; option ally linked by amide; ester and/or urethane groups and (ii) the- halogen free flame retardant system comprises a nitrogen containing:
flame retardant. Flame retardant thermoplastic composition according to claim 1, wherein the copo^ester eiastomer comprises hard, blocks and soft blocks consisting of segments of hafd and: soft polyester polymers linked by urethane groups, Flarrfiferetardanttnemroplastic.composition according.to claim. 1 .or2, wnerein the csepalyester-ester eiastomer is present in^an amount of at least 50 wt. %, relBta*e to the total weight of polymer in the composition. Flam* retardant thermoplastic composition according to any oflciaims 1-3, wnssrein-the nitrogen containing fiame retardant comprises a meiamine based: flarna retardant.
Flarrae?netapdant thermoplastic composition according to any oftciaims 1-4, wrtraprctte nitrogen containing flame retardant is present in aff-amount be|y«»eEr 7.5 and 40wl.%, relative, to the totai weight of theffanje retardant tosanpaplststtc composition.
Flame retardact thermoplastic, composition according to any of claims 1-5, consisting of
A) t&e- copoiyester elastomer (i) of claim ', and optionally
B) one or more other polymeric components, wherein (A) is piesent in a amount of at reast 50 wt.% relative to the total weight of (A| and (B), and wherein the sum of (A) and (B) is 20-100. wt.%, relative to tie-total weight of the-flame-retardec thermoplastic composition,
) between 7.5 and 40 wi.% of tne nitrogen containing flame retardant (it) of
claim 1. and optionally
D) Q-1G wt% of ane or more other haiogen free flame retardant components,
: E) CTr-5Q'wt.%-of one or more filters-and reinforcing- agents, and
F) G-20 wt.%-.of one or more other auxiliary*additives, wheceirr the. sum of (A;-(F: is 100 % and wherein the weight; percentages of (C), (O), (E) and (F) are. relative to the total weight of the flacnef retarded. thermoplastic: composition.
7. Use of a fiame retardant thermoplastic composition according, to any of claims
1-6 iff a moulding process for making an injection moulded pat; an extrusion rnoufeted: parro? an overmouldec oart.
8t Shaoing. process for making a moulded-part comprising a step! wherein the
rrtauki&c. parr is snaped by injection moulding or extrusion mo#dfeg of an etastomer comoositior. according to any of claims " -6, or overmoulding of an

etestomer corriDosrtion according to any of claims i-6 over a core' pan.
9. Mauldec oar. at yeast cartly mace from a flame reiarcant ihernhapiastic
elastomer comccsitior according ic any ofciaims '-c. oreferabiyoeing-a an injection mouJdec car . an extrusion moulded oar or ar over-mouidec pan.

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Patent Number

272789

Indian Patent Application Number

10462/DELNP/2008

PG Journal Number

18/2016

Publication Date

29-Apr-2016

Grant Date

27-Apr-2016

Date of Filing

17-Dec-2008

Name of Patentee

DSM IP ASSETS B.V.

Applicant Address

HET OVERLOON 1, NL-6411 TE HEERLEN, THE NETHERLANDS

Inventors:

#	Inventor's Name	Inventor's Address
1	SCHMIDT, ANGELIKA	ELISABETHSTRASSE 10, D-52538 SELFKANT, GERMANY

PCT International Classification Number

C08K 5/00

PCT International Application Number

PCT/EP2007/005388

PCT International Filing date

2007-06-19

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	06015751.8	2006-07-28	EPO