Flame retardant thermoplastic polyurethane

Abstract

The present invention relates to a composition (C1) comprising a thermoplastic polyurethane (TPU-1); at least one phosphorous containing additive (PA-1) selected from the group consisting of derivatives of phosphinic acid, phosphonic acid and phosphoric acid; and at least one layered silicate (SA-1). The present invention furthermore relates to a molded body, comprising said composition as well as the use of the composition according to the present invention for producing a molded body, in particular a cable sheathing.

Description

[0001] 241057W001

[0002] Flame retardant thermoplastic polyurethane

[0003] The present invention relates to a composition (C1) comprising a thermoplastic polyurethane (TPU-1); at least one phosphorous containing additive (PA-1) selected from the group consisting of derivatives of phosphinic acid, phos- phonic acid and phosphoric acid; and at least one layered silicate (SA-1). The present invention furthermore relates to a molded body, comprising said composition as well as the use of the composition according to the present invention for producing a molded body, in particular a cable sheathing.

[0004] Flame-retarded thermoplastic polyurethanes are used especially in cable production as cable sheathings. A common requirement here is for thin cables having thin cable sheathings which not only pass the relevant flame tests (e.g. VW1) but also have adequate mechanical properties.

[0005] TPU materials have a tendency to flow since the urethane linkages are cleaved upon temperature elevation. In vertical flame tests the flowing of the TPU has the result that the material layers facing the flame flow downward and expose new material to the flame. The formation of a stable protective layer is therefore generally only achievable with high flame retardant fill levels. However, these high levels result in a drop in performance, for example a markedly reduced tensile strength.

[0006] Different combinations of flame retardants have been used for thermoplastic polyurethanes.

[0007] Melamine cyanurate has also long been known as a flame retardant for engineering plastics. PCT / EP2015 / 053192 discloses compositions comprising a thermoplastic polyurethane, melamine cyanurate and a combination of phos- phorus-containing flame retardants. According to PCT / EP2015 / 053192 these compositions have the advantage of good flame retardancy combined with good mechanical properties and good chemicals resistance.

[0008] However, there are tendencies to replace melamine based materials since it is in discussion that melamine cyanurate may be suspected of causing cancer and suspected to damage the fertility.

[0009] Starting from the prior art the present invention accordingly has for its object to provide flame-retarded thermoplastic polyurethanes having good mechanical properties and good flame retardancy properties avoiding melamine containing materials.

[0010] According to the present invention, this object has been solved by a composition (C1) comprising

[0011] (I) a thermoplastic polyurethane (TPU-1);

[0012] (II) at least one phosphorous containing additive (PA-1) selected from the group consisting of derivatives of phosphinic acid, phosphonic acid and phosphoric acid;

[0013] (ill) at least one layered silicate (SA-1). 241057W001

[0014] - 2 -

[0015] It has been found that, surprisingly, the compositions of the invention have an optimized profile of properties as a result of the combination of the components of the invention, especially for use as cable sheathing. It has been found that, surprisingly, the compositions according to the invention have improved properties compared to the compositions known from the prior art, for example good mechanical properties, excellent flame retardancy, low toxicity and low corrosiveness of the smoke gases.

[0016] The composition according to the present invention comprises a thermoplastic polyurethane (TPU-1); at least one phosphorous containing additive (PA-1) selected from the group consisting of derivatives of phosphinic acid, phos- phonic acid and phosphoric acid; and at least one layered silicate (SA-1).

[0017] In principle, the use of layered silicates in compositions comprising thermoplastic polyurethanes is known to the person skilled in the art. Suitable layered silicates are in principle also known. Suitable layered silicates are also known as phyllosilicates.

[0018] According to a further embodiment, the present invention is also directed to the composition as disclosed above, wherein the layered silicate (SA-1) is an organically intercalated phyllosilicate.

[0019] Among the two-layer minerals are especially kaolinite and serpentine, and among the three-layer minerals are especially montmorillonite, and also the micas. The clay minerals are important phyllosilicates, and bentonites are preferably used.

[0020] In another preferred embodiment, intercalated phyllosilicates are used. Starting phyllosilicates for said intercalated phyllosilicates are preferably swellable smectites, such as montmorillonite, hectorite, saponite, beidellite, and bentonite.

[0021] Particularly suitable are intercalated phyllosilicate with a layer spacing which is at least 10% greater than that of the starting phyllosilicate.

[0022] It is more preferable that these are organically intercalated phyllosilicates which have a layer separation of about 1 .5 nm to 4 nm. Said phyllosilicates have preferably been intercalated with quaternary ammonium compounds, with protonated amines, with organic phosphonium ions, and / or with aminocarboxylic acids. According to a further embodiment, the present invention is also directed to the composition as disclosed above, wherein the layered silicates is intercalated with a component (Cl) selected from the group consisting of quaternary ammonium compounds, protonated amines, organic phosphonium ions, and aminocarboxylic acids. 241057W001

[0023] - 3 -

[0024] Preferably, the layered silicate is present in composition (C1) in an amount in the range of from 1 to 10% by weight based on the overall composition, more preferable in an amount in the range of from 2 to 6% by weight based on the overall composition, in particular in an amount in the range of from 2 to 4% by weight based on the overall composition.

[0025] According to a further embodiment, the present invention is also directed to the composition as disclosed above, wherein the layered silicate (SA-1) is present in an amount in the range of from 1 to 10% by weight based on the overall composition.

[0026] Composition (C1) further comprises at least one phosphorous containing additive (PA-1) selected from the group consisting of derivatives of phosphinic acid, phosphonic acid and phosphoric acid.

[0027] The ratio of the components may vary in broad ranges. It has been found that the ratio of the layered silicate (SA-1) and the phosphorous containing additive (PA-1) preferably is in the range of from 1 :2 to 1 :4.

[0028] Suitable derivatives of phosphinic acid, phosphonic acid and phosphoric acid are in principle known as flame retardants for thermoplastic polyurethanes.

[0029] Component (PA-1) may for example be selected from derivatives of phosphinic acid such as salts comprising an organic or inorganic cation or from organic esters. Organic esters are derivatives of phosphinic acid in which at least one oxygen atom bonded directly to the phosphorus has been esterified with an organic radical. In a preferred embodiment the organic ester is an alkyl ester and in another preferred embodiment an aryl ester. It is particularly preferable when all hydroxyl groups of the phosphinic acid have been esterified.

[0030] Suitable phosphinic esters have the general formula R1R2(P=O)OR3, wherein all three organic groups R1, R2and R3may be identical or different. The radicals R1, R2and R3are either aliphatic or aromatic and have 1 to 20 carbon atoms, preferably 1 to 10, more preferably 1 to 3. Preferably at least one of the radicals is aliphatic, preferably all of the radicals are aliphatic, very particularly preferably R1and R2are ethyl radicals. It is more preferable when R3too is an ethyl radical or a methyl radical. In a preferred embodiment R1, R2and R3are simultaneously ethyl radicals or methyl radicals.

[0031] Also preferred are phosphinates, i.e. the salts of phosphinic acid. The R1and R2radicals are either hydrogen, aliphatic or aromatic and have 1 to 20 carbon atoms, preferably 1 to 10, more preferably 1 to 3. Preferably at least one of the radicals is aliphatic, preferably all of the radicals are aliphatic, very particularly preferably R1and R2are ethyl radicals. Preferred salts of phosphinic acids are aluminum salts, calcium salts or zinc salts, more preferably aluminum salts or zinc salts. A preferred embodiment is diethylaluminum phosphinate. 241057W001

[0032] - 4 -

[0033] Suitable are also alkali metal hypophosphite salts, such as alkali metal salts, alkaline earth metal salts, aluminum salts, titanium salts and zinc salts, in particular aluminum hypophosphite salts and calcium hypophosphite salts.

[0034] In a further embodiment the present invention therefore relates to a composition as described hereinabove, wherein the phosphinate is selected from the group consisting of aluminum phosphinates or zinc phosphinates.

[0035] According to a further embodiment, the present invention is also directed to the composition as disclosed above, wherein the phosphorus containing additive (PA-1) is selected from the group consisting of derivatives of phosphinic acid.

[0036] The proportion of the phosphorus containing additive (PA-1) in the composition according to the invention is for example in the range from 1 % to 30% by weight based on the total composition, in particular 5% to 20% by weight based on the total composition, preferably in the range from 8% to 12% by weight based on the total composition.

[0037] According to a further embodiment, the present invention is also directed to the composition as disclosed above, wherein the phosphorus containing additive (PA-1) is present in the composition in an amount in the range of from 1 to 30% by weight based on the overall composition.

[0038] It is preferable in the context of the present invention to employ phosphorus containing additive (PA-1), wherein the particles have an average particle diameter D50 in the range from 0.1 m to 100 pm, preferably from 0.5 pm to 60 pm, particularly preferably 20 pm to 40 pm. The particles preferably have an average particle diameter D95 of less than 100 pm, more preferably of less than 90 pm, in particular of less than 60pm.. In the context of the present invention the particles preferably have an average particle diameter D50 in the range from 0.1 pm to 100 pm and an average particle diameter D95 of less than 100 pm. In the context of the present invention the particle size distribution may be monomodal or else multimodal, for example bimodal. The particle soze may for example be determined by laser diffraction using a wet dispersion in aceton (device: Malvern MS2000 / 2000E).

[0039] According to a further embodiment of the present invention, the phosphorous containing additive (PA-1) may also be selected from the group consisting of phosphoric acid esters. Suitable phosphoric acid esters are in principle known to the person skilled in the art.

[0040] According to the present invention it is also possible that the composition (C1) comprises a further phosphorous containing additives in addition to (PA-1), preferably a second phosphorous containing additive (PA-2) selected from the group consisting of derivatives of phosphoric acid or phosphonic acid.

[0041] According to a further embodiment, the present invention is also directed to the composition as disclosed above, wherein the composition comprises at least a second phosphorous containing additive (PA-2) selected from the group consisting of derivatives of phosphoric acid or phosphonic acid. 241057W001

[0042] - 5 -

[0043] Preferably, component (PA-2) is a phosphoric acid ester, more preferably a tri-ester, more preferred a trialkyl phosphate or a triaryl phosphate, preferably triphenyl phosphate.

[0044] Preferably, the phosphoric ester has the general Formula 1 :

[0045] Formula 1 : where R denotes substituted alkyl, cycloalkyl, or phenyl groups, and n is an integer in the range from 1 to 15.

[0046] If R in the general formula (1) is an alkyl moiety, alkyl moieties that preferably are used are those having from 1 to 8 carbon atoms. The cyclohexyl is a preferred example of the cycloalkyl groups. In other preferred embodiments R denotes a phenyl or alkyl-substituted phenyl.

[0047] Preferably, n is 1, or an integer from 3 to 6.

[0048] Preferably, the second phosphorous containing additive (PA-2) is an aromatic phosphoric acid ester.

[0049] Preferably, the phosphoric acid ester is selected from the group consisting of resorcinol bis-diphenyl phosphate (RDP), bisphenol-A bis- (diphenyl phosphate) (BDP), and diphenylkresyl phosphate (DPK), or is a corresponding oligomer, or is a mixture thereof. The oligomer preferably has an average degree of oligomerization of n = 3 to 6.

[0050] Preferably, the composition comprises resorcinol bis-diphenyl phosphate (RDP), more preferred in the form of an oligomer with an average degree of oligomerization of n = 3 to 6. Preferably, resorcinol bis-diphenyl phosphate is used in the context of the present invention with a content of triphenyl phosphate of less than 2% by weight based on the weight of the bis-diphenyl phosphate used, preferably less than 0.5 % by weight based on the weight of the bis- diphenyl phosphate used, in particular less than 0.1 % by weight based on the weight of the bis-diphenyl phosphate used. 241057W001

[0051] - 6 -

[0052] Preferably, the amount of the sum of components (PA-1) and (PA-2) in the composition is in the range of from 1 weight-% to 25 weight-%, more preferably from 5 weight-% to 20 weight-%, more preferably from 8 weight-% to 15 weight-%.

[0053] Preferably, the second phosphorous containing additive (PA-2), preferably the flame retardant, is liquid, preferably is liquid at a temperature of 21 °C. Typically, this flame retardant beside its flame-retardant properties also has a softening effect for the composition.

[0054] According to the present invention, the phosphorous containing additive (PA-2) in present in composition (C1) in an amount in the range of from 1 to 15 % by weight, based on the weight of the composition (C1), in particular in the range of from 1 % by weight to 10 % by weight, most preferably in the range of from 2 % by weight to 5 % by weight.

[0055] According to a further embodiment, the present invention is also directed to the composition as disclosed above, wherein the phosphorus containing additive (PA-2) is present in the composition in an amount in the range of from 1 to 15% by weight based on the overall composition.

[0056] It has been found that in particular the combination of phyllosilicate with phosphinate or phosphoric acid ester or particularly preferably the combination of phyllosilicate with phosphinate and phosphoric acid ester at the same time produces excellent results. The compositions which additionally contain a further liquid phosphorus compound, preferably RDP, can be processed particularly well in extrusion. Preferably, less nozzle abrasion is observed.

[0057] Composition (C1) may comprise further components and also further flame retardants. However, preferably, no melamine or derivatives are added to composition (C1).

[0058] According to a further embodiment, the present invention is also directed to the composition as disclosed above, wherein the composition is free of melamine and derivatives of melamine.

[0059] According to the invention the composition preferably is free from melamine and derivatives of melamine. In the context of the present invention "free from melamine and derivatives of melamine” is to be understood as meaning that the composition comprises less than 50 ppm of melamine and derivatives of melamine, preferably less than 20 ppm of melamine and derivatives of melamine. In a preferred embodiment the composition comprises 0 ppm of melamine and derivatives of melamine.

[0060] In the context of the present application melamine and derivatives of melamine is to be understood as meaning inter alia all customary and commercially available product qualities.

[0061] The composition of the invention further comprises at least one thermoplastic polyurethane. Thermoplastic polyurethanes are known in principle. Production is typically effected by reaction of the components (a) isocyanates and (b) 241057W001

[0062] - 7 - isocyanate-reactive compounds and optionally (c) chain extenders optionally in the presence of at least one (d) catalyst and / or (e) customary auxiliaries and / or additives. The components (a) isocyanate, (b) isocyanate-reactive compounds, (c) chain extenders are also referred to individually or collectively as building block components.

[0063] In the context of the present invention the typically employed isocyanates and isocyanate-reactive compounds are suitable in principle.

[0064] Preferably employed organic isocyanates (a) include aliphatic, cycloaliphatic, araliphatic and / or aromatic isocyanates, more preferably tri-, tetra-, penta-, hexa-, hepta- and / or octamethylene diisocyanate, 2-methyl pentamethylene 1 ,5-diisocyanate, 2-ethylbutylene 1 ,4-diisocyanate, pentamethylene 1,5-diisocyanate, butylene 1,4-diisocyanate, 1- isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), 1,4- and / or 1 ,3-bis(isocy- anatomethyl)cyclohexane (HXDI),1,4-cyclohexane diisocyanate, 1 -methyl-2,4- and / or -2,6-cyclohexane diisocyanate and / or 4,4'-, 2,4'- and 2,2'-dicyclohexylmethane diisocyanate, 2,2'-, 2,4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), 1 ,5-naphthylene diisocyanate (NDI), 2,4- and / or 2,6-tolylene diisocyanate (TDI), 3,3’-dimethyl diphenyl diisocyanate, 1 ,2-diphenylethane diisocyanate and / or phenylene diisocyanate. It is particularly preferable to employ 4,4'- MDI.

[0065] In a further embodiment the present invention therefore relates to a composition as described hereinabove, wherein the thermoplastic polyurethane is based on diphenylmethane diisocyanate (MDI).

[0066] Employable isocyanate-reactive components (b) include in principle all suitable compounds known to those skilled in the art. According to the invention at least one diol is used as the isocyanate-reactive compound (b).

[0067] Any suitable diols may be employed in the context of the present invention, for example polyether diols or polyester diols or mixtures of two or more thereof.

[0068] Any suitable polyesterdiols may in principle be employed according to the invention, wherein in the context of the present invention the term polyesterdiol also comprises polycarbonate diols.

[0069] One embodiment of the present invention employs a polycarbonate diol or a polytetrahydrofuran polyol. Suitable polytetrahydrofuran polyols have a molecular weight for example in the range from 500 to 5000 g / mol, preferably 500 to 2000 g / mol, particularly preferably 800 to 1200 g / mol.

[0070] Suitable polycarbonate diols include for example polycarbonate diols based on alkanediols. Suitable polycarbonate diols are strictly difunctional OH-functional polycarbonate diols, preferably strictly difunctional OH-functional aliphatic polycarbonate diols. Suitable polycarbonate diols are for example based on 1 ,4-butanediol, 1 ,5-pentanediol or 1,6- hexanediol, in particular 1 ,4-butanediol, 1 ,5-pentanediol, 1 ,6-hexanediol, 3-methylpentane-(1,5)-diol or mixtures 241057W001

[0071] - 8 - thereof, particularly preferably 1 ,4-butanediol, 1 ,5-pentanediol, 1 ,6-hexanediol or mixtures thereof. Preferably employed in the context of the present invention are polycarbonate diols based on 1 ,4-butanediol and 1 ,6-hexanediol, polycarbonate diols based on 1,5-pentanediol and 1 ,6-hexanediol, polycarbonate diols based on 1 ,6-hexanediol and mixtures of two or more of these polycarbonate diols.

[0072] Preferably employable chain extenders (c) include aliphatic, araliphatic, aromatic and / or cycloaliphatic compounds having a molecular weight of 0.05 kg / mol to 0.499 kg / mol, preferably difunctional compounds, for example diamines and / or alkanediols having 2 to 10 carbon atoms in the alkylene radical, di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona- and / or decaalkylene glycols having 3 to 8 carbon atoms, especially 1 ,2-ethylene glycol, 1 ,3-propanediol, 1 ,4- butanediol, 1 ,6-hexanediol, preferably corresponding oligo- and / or polypropylene glycols, wherein mixtures of the chain extenders may also be employed. The compounds (c) preferably have only primary hydroxyl groups, 1,4-bu- tanediol or a mixture of 1 ,3-propanediol and 1 ,4-butanediol being very particularly preferred.

[0073] It is also possible according to the invention to employ a polyhydric alcohol, for example propanediol and / or a further diol, that has been obtained at least partially from renewable raw materials. It is possible that the polyhydric alcohol has been partially or entirely obtained from renewable raw materials. According to the invention at least one of the employed polyhydric alcohols may have been at least partially obtained from renewable raw materials.

[0074] So-called bio-1, 3-propanediol is obtainable for example from maize and / or sugar. A further possibility is the conversion of glycerol wastes from biodiesel production. In a further preferred embodiment of the invention the polyhdric alcohol is 1, 3-propanediol that has been at least partially obtained from renewable raw materials.

[0075] In a further embodiment the present invention accordingly relates to a composition as described hereinabove, wherein the thermoplastic polyurethane is based to an extent of at least 30% on renewable raw materials. One suitable method of determination is the C14 method for example.

[0076] In a preferred embodiment catalysts (d) which accelerate especially the reaction between the NCO groups of the diisocyanates (a) and the hydroxyl groups of the isocyanate-reactive compound (b) and the chain extender (c) are tertiary amines, especially triethylamine, dimethylcyclohexylamine, N-methylmorpholine, N,N'-dimethylpiperazine, 2- (dimethylaminoethoxy)ethanol, diazabicyclo[2.2.2]octane; in another preferred embodiment, these are organic metal compounds such as titanate esters, iron compounds, preferably iron(lll) acetylacetonate, tin compounds, preferably tin diacetate, tin dioctoate, tin dilaurate or the dialkyltin salts of aliphatic carboxylic acids, preferably dibutyltin diacetate, dibutyltin dilaurate, or bismuth salts in which bismuth is preferably in the oxidation state 2 or 3, especially 3. Salts of carboxylic acids are preferred. Carboxylic acids employed are preferably carboxylic acids having 6 to 14 carbon atoms, particularly preferably having 8 to 12 carbon atoms. Examples of suitable bismuth salts are bismuth(lll) neodecanoate, bismuth 2-ethylhexanoate and bismuth octanoate. 241057W001

[0077] - 9 -

[0078] The catalysts (d) are preferably used in amounts of 0.0001 to 0.1 part by weight per 100 parts by weight of the isocyanate-reactive compound (b). It is preferable to employ tin catalysts, especially tin dioctoate.

[0079] Not only catalysts (d) but also customary auxiliaries (e) may be added to the synthesis components (a) to (c). Examples include surface-active substances, fillers, further flame retardants, nucleation agents, oxidation stabilizers, lubrication and demolding aids, dyes and pigments, optionally stabilizers, for example against hydrolysis, light, heat or discoloration, inorganic and / or organic fillers, reinforcers and plasticizers. Suitable auxiliary and additive substances may be found for example in Kunststoffhandbuch, volume VII, edited by Vieweg and Hdchtlen, Carl Hanser Verlag, Munich 1966 (p. 103-113).

[0080] Production processes for thermoplastic polyurethanes are disclosed for example in EP 0 922 552 A1, DE 101 03424 A1 or WO 2006 / 072461 A1 . Production is typically effected on a belt apparatus or in a reactive extruder, but can also be effected on the laboratory scale, for example in a manual casting method. Depending on the physical properties of the components these are all mixed with one another directly or individual components are premixed and / or prereacted, for example to give prepolymers, and only then subjected to polyaddition. In a further embodiment a thermoplastic polyurethane is first produced from the building block components, optionally together with catalyst, into which auxiliaries may optionally also be incorporated. In that case, at least one flame retardant is introduced into this material and distributed homogeneously. Homogeneous distribution is preferably effected in an extruder, preferably in a twin-screw extruder. To adjust the hardness of the TPUs, the amounts used of building block components (b) and (c) can be varied within relatively broad molar ratios, typically with rising hardness as the content of chain extender (c) increases.

[0081] For producing thermoplastic polyurethanes, for example those having a Shore A hardness of less than 95, preferably from 95 to 80 Shore A, particularly preferably about 85A, the substantially difunctional polyhydroxyl compounds (b) and chain extenders (c) may advantageously be employed in molar ratios of 1 : 1 to 1 : 5, preferably 1 : 1 .5 to 1 : 4.5 so that the resulting mixtures of the building block components (b) and (c) have a hydroxyl equivalent weight of greater than 200 and in particular from 230 to 450 while for producing harder TPUs, for example those having a Shore A hardness of greater than 98, preferably from 55 to 75 Shore D, the molar ratios of (b): (c) are in the range from 1 : 5.5 to 1 : 15, preferably from 1 : 6 to 1 : 12 so that the obtained mixtures of (b) and (c) have a hydroxyl equivalent weight of 110 to 200, preferably of 120 to 180.

[0082] The thermoplastic polyurethane employed according to the invention preferably has a hardness in the range from 65A to 80D determined according to DIN ISO 48-4 (Shore hardness test A (3s)), preferably in the range from 80A to 80D determined according to DIN ISO 7619-1, more preferably in the range from 80A to 85A determined according to DIN ISO 7619-1.

[0083] The composition according to the invention comprises the at least one thermoplastic polyurethane in an amount in the range from 60% by weight to 93% by weight based on the total composition, especially in the range from 65% by 241057W001

[0084] - 10 - weight to 92% by weight based on the total composition, preferably in the range from 68% by weight to 90% by weight, more preferably in the range from 70% by weight to 88% by weight and particularly preferably in the range from 70% by weight to 85% by weight in each case based on the total composition.

[0085] In a further embodiment the present invention therefore relates to a composition as described hereinabove, wherein the proportion of the thermoplastic polyurethane in the composition is in the range from 60% by weight to 93% by weight based on the total composition.

[0086] The sum of all components in the composition amounts to 100% by weight in each case.

[0087] Preferably employed according to the invention are thermoplastic polyurethanes where the thermoplastic polyurethane has an average molecular weight (Mw) in the range from 50 000 to 500 000 Dalton. Unless otherwise noted, the mean molecular weights and the weight-average molecular weight as outlined herein are determined by gel permeation chromatography, preferably according to DIN 55672-1 whereas dimethylformamide (DMF) is used as solvent. The upper limit for the average molecular weight (Mw) of the thermoplastic polyurethanes is generally determined by processibility as well as the spectrum of properties desired. It is more preferable when the thermoplastic polyurethane has an average molecular weight (Mw) in the range from 100,000 to 300,000 Da, more preferably in the range from 120,000 to 250,000 Da, especially preferably in the range from 150,000 to 250,000 Da.

[0088] In a further embodiment the present invention therefore relates to a composition as described hereinabove, wherein the thermoplastic polyurethane has an average molecular weight (Mw) of greater than 50 000 Da.

[0089] Suitable methods for preparing the composition according to the present invention are also known.

[0090] The mixing of the thermoplastic polyurethane with the other components is effected in a mixing unit which is preferably an internal kneader or an extruder, preferably a twin-screw extruder. In a preferred embodiment at least one flame retardant introduced into the mixing unit in the at least one further step is liquid, i.e. liquid at a temperature of 21 °C. In another preferred embodiment of the use of an extruder the introduced flame retardant is at least partially liquid at a temperature prevailing downstream of the filling point in the flow direction of the material in the extruder.

[0091] According to the invention the composition may comprise further flame retardants, also including phosphorus-con- taining flame retardants for example. Mechanical properties and flame retardancy properties are optimized according to the invention through the combination of the various flame retardants.

[0092] Preferably, no metal hydroxides, in particular hydroxides of magnesium, calcium, zinc and / or aluminum are added to composition (C1). 241057W001

[0093] - 11 -

[0094] Preferably, the composition comprises less than 10% by weight of metal hydroxides, in particular hydroxides of magnesium, calcium, zinc and / or aluminum, more preferable less than 5% by weight, in particular less than 1 % by weight, in each case based on the total weight of the composition.

[0095] According to a further embodiment, the present invention is also directed to the composition as disclosed above, wherein the composition is free of hydroxides of magnesium, calcium, zinc and / or aluminum.

[0096] In the context of the present invention "free from hydroxides of magnesium, calcium, zinc and / or aluminum” is to be understood as meaning that the composition comprises less than 50 ppm of hydroxides of magnesium, calcium, zinc and / or aluminum, preferably less than 20 ppm of hydroxides of magnesium, calcium, zinc and / or aluminum. In a preferred embodiment the composition comprises 0 ppm of hydroxides of magnesium, calcium, zinc and / or aluminum.

[0097] In the context of the present application hydroxides of magnesium, calcium, zinc and / or aluminum is to be understood as meaning inter alia all customary and commercially available product qualities.

[0098] Preferably, no calcium carbonate is added to composition (C1). Preferably, the composition comprises less than 10% by weight of calcium carbonate, more preferable less than 5% by weight, in particular less than 1 % by weight, in each case based on the total weight of the composition.

[0099] According to a further embodiment, the present invention is also directed to the composition as disclosed above, wherein the composition is free of calcium carbonate.

[0100] In the context of the present invention "free from calcium carbonate” is to be understood as meaning that the composition comprises less than 50 ppm of calcium carbonate, preferably less than 20 ppm of calcium carbonate. In a preferred embodiment the composition comprises 0 ppm of calcium carbonate.

[0101] In the context of the present application calcium carbonate is to be understood as meaning inter alia all customary and commercially available product qualities.

[0102] According to the invention the composition may also comprise further constituents, for example standard auxiliary and additive substances for thermoplastic polyurethanes. The composition according to the invention may comprise fillers or dyes for example, preferably in an amount in the range from 0.1% to 5% by weight based on the total composition. In a further embodiment the present invention accordingly relates to a composition as described hereinabove, wherein the composition comprises titanium dioxide in an amount in the range from 0.1% to 5% by weight based on the total composition. 241057W001

[0103] - 12 -

[0104] The present invention also relates to the use of the composition according to the invention comprising at least one flame-retarded thermoplastic polyurethane as described hereinabove for the production of coatings, damping elements, bellows, films or fibers, molded articles, floors for buildings and transport, nonwoven fabrics, preferably seals, rollers, shoe soles, hoses, cables, cable connectors, cable sheathings, cushions, laminates, profiles, belts, saddles, foams, plug connectors, trailing cables, solar modules, automotive trim. Use for the production of cable sheathings is preferred. Production is preferably effected from granulates by injection molding, calendering, powder sintering or extrusion and / or by additional foaming of the composition according to the invention.

[0105] According to a further aspect, the present invention is also directed to the use of the composition (C1 ) as disclosed above for producing a molded body, in particular a cable sheathing.

[0106] Furthermore, according to a further aspect, the present invention is also directed to a molded body, comprising a composition (C 1) as disclosed above.

[0107] The compositions according to the invention allow the production of particularly thin cables, for example cables having an external diameter of less than 2 mm and a wall thickness of less than 0.5 mm. In a further embodiment the present invention accordingly also relates to the use of a composition as described hereinabove for the production of cable sheathings having a wall thickness in the range from 0.1 to 0.5 mm.

[0108] Further embodiments of the present invention are apparent from the claims and the examples. It will be appreciated that the features of the subject matter / process according to the invention or of the uses according to the invention recited hereinabove and elucidated hereinbelow may be used not only in the combination specified in each case but also in other combinations without departing from the scope of the invention. Thus, for example the combination of a preferred feature with a particularly preferred feature or of a feature not characterized further with a particularly preferred feature etc. is thus also encompassed implicitly even if this combination is not mentioned explicitly.

[0109] The present invention is further illustrated by the following set of embodiments and combinations of embodiments resulting from the dependencies and back-references as indicated. In particular, it is noted that in each instance where a range of embodiments is mentioned, for example in the context of a term such as "The process of any one of embodiments 1 to 3", every embodiment in this range is meant to be explicitly disclosed for the skilled person, i.e. the wording of this term is to be understood by the skilled person as being synonymous to "The process of any one of embodiments 1, 2 and 3". Further, it is explicitly noted that the following set of embodiments represents a suitably structured part of the general description directed to preferred aspects of the present invention, and, thus, suitably supports, but does not represent the claims of the present invention.

[0110] It is explicitly noted that the above set of embodiments represents a suitably structured part of the general description directed to preferred aspects of the present invention, and, thus, suitably supports, but does not represent the 241057W001

[0111] - 13 - claims of the present invention.

[0112] 1. A composition (C1) comprising

[0113] (i) a thermoplastic polyurethane (TPU-1);

[0114] (ii) at least one phosphorous containing additive (PA-1) selected from the group consisting of derivatives of phosphinic acid, phosphonic acid and phosphoric acid;

[0115] (ill) at least one layered silicate (SA-1).

[0116] 2. The composition according to embodiment 1, wherein the layered silicate (SA-1) is an organically intercalated phyllosilicate.

[0117] 3. A composition (C1) comprising

[0118] (I) a thermoplastic polyurethane (TPU-1);

[0119] (ii) at least one phosphorous containing additive (PA-1) selected from the group consisting of derivatives of phosphinic acid, phosphonic acid and phosphoric acid;

[0120] (ill) at least one layered silicate (SA-1), wherein the layered silicate (SA-1) is an organically intercalated phyllosilicate.

[0121] 4. The composition according to any one of embodiments 1 to 3, wherein the layered silicates is intercalated with a component (Cl) selected from the group consisting of quaternary ammonium compounds, protonated amines, organic phosphonium ions, and aminocarboxylic acids.

[0122] 5. The composition according to any one of embodiments 1 to 4, wherein the layered silicate (SA-1) is present in an amount in the range of from 1 to 10% by weight based on the overall composition.

[0123] 6. A composition (C1) comprising

[0124] (I) a thermoplastic polyurethane (TPU-1);

[0125] (ii) at least one phosphorous containing additive (PA-1) selected from the group consisting of derivatives of phosphinic acid, phosphonic acid and phosphoric acid;

[0126] (ill) at least one layered silicate (SA-1), wherein the layered silicate (SA-1) is present in an amount in the range of from 1 to 10% by weight based on the overall composition.

[0127] 7. The composition according to any one of embodiments 1 to 6, wherein the composition is free of melamine and derivatives of melamine.

[0128] 8. A composition (C1) comprising 241057W001

[0129] - 14 -

[0130] (i) a thermoplastic polyurethane (TPU-1);

[0131] (ii) at least one phosphorous containing additive (PA-1) selected from the group consisting of derivatives of phosphinic acid, phosphonic acid and phosphoric acid;

[0132] (ill) at least one layered silicate (SA-1), wherein the composition is free of melamine and derivatives of melamine.

[0133] 9. The composition according to any one of embodiments 1 to 8, wherein the phosphorus containing additive (PA-1) is selected from the group consisting of derivatives of phosphinic acid.

[0134] 10. The composition according to any one of embodiments 1 to 9, wherein the phosphorus containing additive (PA-1) is present in the composition in an amount in the range of from 1 to 30% by weight based on the overall composition.

[0135] 11. A composition (C1) comprising

[0136] (I) a thermoplastic polyurethane (TPU-1);

[0137] (ii) at least one phosphorous containing additive (PA-1) selected from the group consisting of derivatives of phosphinic acid, phosphonic acid and phosphoric acid;

[0138] (ill) at least one layered silicate (SA-1), wherein the composition is free of melamine and derivatives of melamine, wherein the layered silicate (SA-1) is present in an amount in the range of from 1 to 10% by weight based on the overall composition, and wherein the phosphorus containing additive (PA-1) is present in the composition in an amount in the range of from 1 to 30% by weight based on the overall composition.

[0139] 12. The composition according to any one of embodiments 1 to 11 , wherein the composition comprises at least a second phosphorous containing additive (PA-2) selected from the group consisting of derivatives of phosphoric acid or phosphonic acid.

[0140] 13. The composition according to any one of embodiments 1 to 12, wherein the phosphorus containing additive (PA-2) is present in the composition in an amount in the range of from 1 to 15% by weight based on the overall composition.

[0141] 14. A composition (C1) comprising

[0142] (I) a thermoplastic polyurethane (TPU-1); 241057W001

[0143] - 15 -

[0144] (ii) at least one phosphorous containing additive (PA-1) selected from the group consisting of derivatives of phosphinic acid, phosphonic acid and phosphoric acid;

[0145] (iii) at least one layered silicate (SA-1), wherein the composition is free of melamine and derivatives of melamine, wherein the layered silicate (SA-1) is present in an amount in the range of from 1 to 10% by weight based on the overall composition, and wherein the phosphorus containing additive (PA-1) is present in the composition in an amount in the range of from 1 to 30% by weight based on the overall composition, wherein the composition comprises at least a second phosphorous containing additive (PA-2) selected from the group consisting of derivatives of phosphoric acid or phosphonic acid and the phosphorus containing additive (PA-2) is present in the composition in an amount in the range of from 1 to 15% by weight based on the overall composition.

[0146] 15. A molded body, comprising a composition (C1) according to any one of embodiments 1 to 14.

[0147] 16. A molded body, comprising a composition (C1) comprising

[0148] (i) a thermoplastic polyurethane (TPU-1);

[0149] (ii) at least one phosphorous containing additive (PA-1) selected from the group consisting of derivatives of phosphinic acid, phosphonic acid and phosphoric acid;

[0150] (iii) at least one layered silicate (SA-1).

[0151] 17. The molded body according to embodiment 16, wherein the layered silicate (SA-1) is an organically intercalated phyllosilicate.

[0152] 18. A molded body, comprising a composition (C1) comprising

[0153] (i) a thermoplastic polyurethane (TPU-1);

[0154] (ii) at least one phosphorous containing additive (PA-1) selected from the group consisting of derivatives of phosphinic acid, phosphonic acid and phosphoric acid;

[0155] (iii) at least one layered silicate (SA-1), wherein the layered silicate (SA-1) is an organically intercalated phyllosilicate.

[0156] 19. The molded body according to any one of embodiments 16 to 18, wherein the layered silicates is intercalated with a component (Cl) selected from the group consisting of quaternary ammonium compounds, protonated amines, organic phosphonium ions, and aminocarboxylic acids. 241057W001

[0157] - 16 -

[0158] 20. The molded body according to any one of embodiments 16 to 19, wherein the layered silicate (SA-1) is present in an amount in the range of from 1 to 10% by weight based on the overall composition.

[0159] 21. A molded body, comprising a composition (C1) comprising

[0160] (I) a thermoplastic polyurethane (TPU-1);

[0161] (ii) at least one phosphorous containing additive (PA-1) selected from the group consisting of derivatives of phosphinic acid, phosphonic acid and phosphoric acid;

[0162] (ill) at least one layered silicate (SA-1), wherein the layered silicate (SA-1) is present in an amount in the range of from 1 to 10% by weight based on the overall composition.

[0163] 22. The molded body according to any one of embodiments 16 to 21, wherein the composition is free of melamine and derivatives of melamine.

[0164] 23. A molded body, comprising a composition (C1) comprising

[0165] (I) a thermoplastic polyurethane (TPU-1);

[0166] (ii) at least one phosphorous containing additive (PA-1) selected from the group consisting of derivatives of phosphinic acid, phosphonic acid and phosphoric acid;

[0167] (ill) at least one layered silicate (SA-1), wherein the composition is free of melamine and derivatives of melamine.

[0168] 24. The molded body according to any one of embodiments 16 to 23, wherein the phosphorus containing additive (PA-1) is selected from the group consisting of derivatives of phosphinic acid.

[0169] 25. The molded body according to any one of embodiments 16 to 24, wherein the phosphorus containing additive (PA-1) is present in the composition in an amount in the range of from 1 to 30% by weight based on the overall composition.

[0170] 26. A molded body, comprising a composition (C1) comprising

[0171] (I) a thermoplastic polyurethane (TPU-1);

[0172] (ii) at least one phosphorous containing additive (PA-1) selected from the group consisting of derivatives of phosphinic acid, phosphonic acid and phosphoric acid;

[0173] (ill) at least one layered silicate (SA-1), wherein the composition is free of melamine and derivatives of melamine, 241057W001

[0174] - 17 - wherein the layered silicate (SA-1) is present in an amount in the range of from 1 to 10% by weight based on the overall composition, and wherein the phosphorus containing additive (PA-1) is present in the composition in an amount in the range of from 1 to 30% by weight based on the overall composition.

[0175] 27. The molded body according to any one of embodiments 16 to 26, wherein the composition comprises at least a second phosphorous containing additive (PA-2) selected from the group consisting of derivatives of phosphoric acid or phosphonic acid.

[0176] 28. The molded body according to any one of embodiments 16 to 27, wherein the phosphorus containing additive (PA-2) is present in the composition in an amount in the range of from 1 to 15% by weight based on the overall composition.

[0177] 29. A molded body, comprising a composition (C1) comprising

[0178] (I) a thermoplastic polyurethane (TPU-1);

[0179] (ii) at least one phosphorous containing additive (PA-1) selected from the group consisting of derivatives of phosphinic acid, phosphonic acid and phosphoric acid;

[0180] (ill) at least one layered silicate (SA-1), wherein the composition is free of melamine and derivatives of melamine, wherein the layered silicate (SA-1) is present in an amount in the range of from 1 to 10% by weight based on the overall composition, and wherein the phosphorus containing additive (PA-1) is present in the composition in an amount in the range of from 1 to 30% by weight based on the overall composition, wherein the composition comprises at least a second phosphorous containing additive (PA-2) selected from the group consisting of derivatives of phosphoric acid or phosphonic acid and the phosphorus containing additive (PA-2) is present in the composition in an amount in the range of from 1 to 15% by weight based on the overall composition.

[0181] 30. Use of the composition (C1) according to any one of embodiments 1 to 14 for producing a molded body, in particular a cable sheathing. 241057W001

[0182] - 18 -

[0183] The present invention is further illustrated by the following examples.

[0184] Examples:

[0185] The examples show that the properties are comparable for the inventive mixtures and common flame-retardant TPU based on melamine cyanurate. The inventive mixtures have the advantage of a low corrosivity and a low smoke toxicity.

[0186] 1. Example 1 (starting materials)

[0187] Elastollan 1185A10: TPU of Shore hardness 85 A from BASF Polyurethanes GmbH, Elastogranstrasse 60, 49448 Lemforde, based on polytetrahydrofuran polyol (PTHF) having a molecular weight of 1000, butane-1 ,4- diol, MDI.

[0188] Melapur MC 15 ED: Melamine cyanurate (1 ,3,5-triazine-2,4,6(1 H,3H,5H)-trione, compound with 1,3,5-triazine- 2,4,6-triamine (1 : 1)), CAS #: 37640-57-6, BASF SE, 67056 Ludwigshafen, GERMANY, particle size D99%<1 =50 pm, D50%<=4.5 pm, water content % (w / w)<0.2.

[0189] Melapur 200 / 70: Melaminpolyphosphat (nitrogen content 42-44wt%, phosphorous content 12-14wt%)), CAS #: 218768-84-4, BASF SE, 67056 Ludwigshafen, GERMANY, particle size D99% < / = 70 m, average particle size D50%<= 10 pm, water content % (w / w) < 0,3.

[0190] Fyrolflex RDP: Resorcinol bis(diphenylphosphate), CAS #. 125997-21-9, Supresta Netherlands B.V., Office Park De Hoef, Hoefseweg 1 , 3821 AE Amersfoort, the Netherlands, phosphorous content 10.7%, viscosity at 25° C = 700 mPas, acid number<0.1 mg KOH / g, water content % (w / w) < 0.1.

[0191] Disflamoll DPK: Diphenylcresylphosphate, CAS #: 026444-49-5, LANXESS Deutschland GmbH, 51369 Leverkusen, Deutschland, acid number < 0,1 mg KOH / g, water content % (w / w) < 0,1.

[0192] Exolit OP 1230: Aluminum diethylphosphinate, CAS#: 225789-38-8, Clariant Produkte (Deutschland) GmbH, Chemiepark Knapsack, 50351 Hiirth, average particle size D50% = 20-40 pm, water content % (w / w)<0.2.

[0193] Cloisite 20A: Organic phyllosilicate, white powder, BYK-Chemie GmbH, 46462 Wesel (Germany), bulk density 350kg / m3, density (20°C) 1 ,8 g / cm3, Particle size (D50) <10pm, moisture content < 2,5%, laminar spacing (XRD, d001): 2,7 nm. 241057W001

[0194] - 19 -

[0195] Nofia HM 1100: Polyphosphonate homopolymer, CAS#: 68664-06-2, FRX Polymers (Europe), NV, Haven 507, Scheldelaan 420, 2040 Antwerpen, Belgium, Phosphorus content 10,9%, water content % (w / w) < 0,1, MVR (240°C / 1 ,2kg = 8 cm3 / 10 min). 2. Example 2 (compositions)

[0196] The tables below list compositions in which the parts by weight (PW) of the individual starting materials have been stated. In each case, the mixtures were produced in a ZE 40 A twin-screw extruder from Berstorff with screw length of 35 D, divided into 10-barrel sections. Granules were obtained using an underwater pelletizing unit of Gala.

[0197] Table 1

[0198] Table 2 Table 3 241057W001

[0199] - 20 -

[0200] 3. Example 3 (mechanical performance)

[0201] The mixtures were extruded with an Arenz single-screw extruder having a three-zone screw with a mixing section (screw ratio 1 :3) to give films having a thickness of 1.6 mm. Density, Shore hardness, tensile strength, tear propagation resistance, abrasion and elongation at break of the corresponding test specimens were measured. All compositions have good mechanical properties. The results are compiled in Tables 4 to 6.

[0202] Table 4

[0203] Table 5 Table 6

[0204] 4. Example 4 (Flame Retardancy) 241057W001

[0205] - 21 -

[0206] To evaluate flame retardancy, a test specimen of thickness 5 mm is tested horizontally with radiation of intensity 35 kW / m2in a cone calorimeter in accordance with ISO 5660 part 1 and part 2 (2002-12). The test specimens for the cone measurements with dimensions 100x100x5mm were injection molded using an Arburg 520S with screw diameter 30 mm. The key parameters for the cone measurements for the different materials are given in Tables 7 to 9. The inventive examples show similar THE and PHRR in comparison to the comparative examples.

[0207] Table 7

[0208] Table 8 - n.d.: not determined

[0209] Table 9

[0210] 5. Example 5 (Conductivity and toxicity of the smoke gases)

[0211] The conductivities determined using DIN EN 60754-2 (2015) were found to be much lower for the inventive examples. Therefore, the inventive mixtures appear to be much less corrosive compared to the comparative mixtures. Also, it was found that the inventive examples form less hydrocyanic acid (HCN) during combustion than the comparative mixtures. The ITC value determined using the NF X 70-100 Part 1+2 (2006) is much smaller than found for the comparative examples. The results are given in Tables 10 to 12. 241057W001

[0212] - 22 -

[0213] Table 10 - n.d.: not determine

[0214] Table 12 Literature cited:

[0215] PCT / EP2015 / 053192

[0216] Kunststoffhandbuch, volume VII, edited by Vieweg and Hbchtlen, Carl Hanser Verlag, Munich 1966 (p. 103-113)

[0217] EP 0 922 552 A1

[0218] DE 101 03 424 A1 WO 2006 / 072461 A1

Claims

241057W001- 23 -Claims1. A composition (C1) comprising(i) a thermoplastic polyurethane (TPU-1);(ii) at least one phosphorous containing additive (PA-1) selected from the group consisting of derivatives of phosphinic acid, phosphonic acid and phosphoric acid;(ill) at least one layered silicate (SA-1).

2. The composition according to claim 1, wherein the layered silicate (SA-1) is an organically intercalated phyllosilicate.

3. The composition according to claim 1 or 2, wherein the layered silicates is intercalated with a component (Cl) selected from the group consisting of quaternary ammonium compounds, protonated amines, organic phosphonium ions, and aminocarboxylic acids.

4. The composition according to any one of claims 1 to 3, wherein the layered silicate (SA-1) is present in an amount in the range of from 1 to 10% by weight based on the overall composition.

5. The composition according to any one of claims 1 to 4, wherein the composition is free of melamine and derivatives of melamine.

6. The composition according to any one of claims 1 to 5, wherein the phosphorus containing additive (PA-1) is selected from the group consisting of derivatives of phosphinic acid.

7. The composition according to any one of claims 1 to 6, wherein the phosphorus containing additive (PA-1) is present in the composition in an amount in the range of from 1 to 30% by weight based on the overall composition.

8. The composition according to any one of claims 1 to 7, wherein the composition comprises at least a second phosphorous containing additive (PA-2) selected from the group consisting of derivatives of phosphoric acid or phosphonic acid.

9. The composition according to any one of claims 1 to 8, wherein the phosphorus containing additive (PA-2) is present in the composition in an amount in the range of from 1 to 15% by weight based on the overall composition.

10. A molded body, comprising a composition (C1) according to any one of claims 1 to 9.241057W001- 24 -11. Use of the composition (C1) according to any one of claims 1 to 9 for producing a molded body, in particular a cable sheathing.

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