Flame retardant TPU films

Abstract

The present invention is directed to a film comprising a composition (C1) comprising a thermoplastic polyurethane (TPU-1) in an amount in the range of from 75 to 98 % by weight, and a phosphorous containing additive (PA-1) in an amount in the range of from 2 to 25 % by weight, based on the weight of the composition (C1), wherein the phosphorous containing additive (PA-1) is selected from the group consisting of polyphosphonates and phosphoric acid esters.as well as the use thereof for bonding a first part and a second part, in particular for the application as an adhesive film, preferably for articles for the automobile industry, for machine construction, for consumer goods, batteries, or articles for e-mobility.

Description

[0001] 240882W001

[0002] Flame retardant TPU Films

[0003] The present invention is directed to a film comprising a composition (C1) comprising a thermoplastic polyurethane (TPU-1) in an amount in the range of from 75 to 98 % by weight, and a phosphorous containing additive (PA-1) in an amount in the range of from 2 to 25 % by weight, based on the weight of the composition (C1 ), wherein the phosphorous containing additive (PA-1) is selected from the group consisting of polyphosphonates and phosphoric acid esters, as well as the use thereof for bonding a first part and a second part, in particular for the application as an adhesive film, preferably for articles for the automobile industry, for machine construction, for consumer goods, batteries, or articles for e-mobility.

[0004] Thermoplastic polyurethanes represent a broad family of polymers with great commercial and industrial importance. These materials can be formulated to have a wide range of material properties. Principal applications include films, coatings, elastomers, and foams. Films and coatings can be especially advantageous in protecting substrates from environmental weathering, chemical exposure, heat, and / or abrasion.

[0005] Also, the use of thermoplastic polyurethane in adhesive films is known from the state of the art. For example, EP 1323800 discloses multilayer films that comprise thermoplastic polyurethane films.

[0006] In particular for the application as adhesive in machine construction, high flame resistance is necessary in combination with good adhesive properties. For many applications, adhesives are required which fulfill standard flame tests and have good mechanical properties. For example, transparent flame-retardant thermoplastic polyurethanes comprising flame retardants are known. Thermoplastic polyurethanes comprising liquid flame retardants are particularly suitable for the production of films, especially flat films, as there are no solid flame retardants present. This prevents clogging of the die and makes processing easier. These films have good flame retardancy and are suitable for bonding various substrates. However, the resulting materials have high VOC values, especially during thermoplastic processing at high temperatures, which leads to the formation of harmful substances and strong odors.

[0007] It was therefore an object of the present invention to provide films comprising thermoplastic polyurethanes which are suitable as adhesive and have good mechanical properties and at the same time good VOC values according to VDA norm 278.

[0008] According to the present invention, this object has been solved by a film comprising a composition (C1) comprising a thermoplastic polyurethane (TPU-1) in an amount in the range of from 75 to 98 % by weight, and a phosphorous containing additive (PA-1) in an amount in the range of from 2 to 25 % by weight, based on the weight of the composition (C1), wherein the phosphorous containing additive (PA-1) is selected from the group consisting of polyphosphonates and phosphoric acid esters. 240882W001

[0009] - 2 -

[0010] It has been found that the use of polyphosphonates or phosphoric acid esters as flame retardants allows to prepare films which are odor free and have good flame-retardant properties. The films according to the present invention are particularly suitable as adhesives.

[0011] The film according to the present invention comprises composition (C1). Composition (C1) comprises the thermoplastic polyurethane (TPU-1) in an amount in the range of from 75 to 98 % by weight, and a phosphorous containing additive (PA-1) in an amount in the range of from 2 to 25 % by weight, based on the weight of the composition (C1). The composition (C1) may comprise further additives and further polymers. Preferably, the composition (C1) comprises further polymers in an amount of from 0 to 10 % by weight, in particular in an amount of from 0 to 5 % by weight based on the weight of the composition (C1).

[0012] Preferably, the composition (C1) comprises siloxane polymers in amount of less than 0.1 to 5 % by weight. Particularly preferable, the composition (C1) is free of siloxane polymers. According to a further embodiment, the present invention is also directed to a film as disclosed above, wherein the composition (C1) is free of siloxane polymers.

[0013] Typically, the thermoplastic polyurethane is prepared by reacting an organic isocyanate, preferably an organic diisocyanate, with a polyol, preferably having two functional groups reactive with isocyanate groups, also referred to as polymer diol, and a chain extender.

[0014] To adjust the hardness and melt flow index of the thermoplastic polyurethane (TPU), the molar ratios of the quantities of the building components, can be varied, whereby the hardness and melt viscosity increase with increasing content of isocyanate and chain extender, while the melt flow index decreases.

[0015] The properties of thermoplastic polyurethane (TPU-1) may vary in broad ranges depending on the ratio and the structure of the components used.

[0016] Preferably, the composition has a hardness between 70 Shore A and 60 Shore D, more preferably between 70 Shore A and 100 Shore A, in particular between 75 Shore A and 95 Shore A , more preferably in the range of from 80 Shore A to 90 Shore A measured according to DIN ISO 7619-1 : 2016.

[0017] Preferably, the thermoplastic polyurethane present in the composition (C1) has a weight-average molecular weight of at least 0.04 x 106g / mol, more preferably at least 0.05 x 106g / mol,. The upper limit for the weight-average molecular weight of TPU is generally determined by the processability and the desired range of properties. Preferably the weight-average molecular weight does not exceed 0.5 x106g / mol, more preferably 0.3 x106g / mol, more preferably 0.2 x106g / mol, and more preferably 0.1 x106g / mol. Unless otherwise noted, the molecular weight is determined using GPC according to DIN EN ISO 13885-2:2020. According to the present invention, the weight-average molecular weight of the thermoplastic polyurethane present in the composition (C1) is preferably determined using a sample of the film according to the present invention, i.e. after the preparation of the film. 240882W001

[0018] - 3 -

[0019] Suitable isocyanates, polyols and chain extender for the preparation of thermoplastic polyurethanes are in principle known to the person skilled in the art.

[0020] Preferably, the isocyanate used for the synthesis of the thermoplastic polyurethane (TPU-1) is a diisocyanate. Further preferred the isocyanate is selected from the group consisting of aliphatic, cycloaliphatic, araliphatic and aromatic isocyanates, or is a mixture thereof.

[0021] The isocyanate more preferably is selected from the group consisting of tri-, tetra-, penta-, hexa-, hepta- and / or octamethylene diisocyanate, 2-methyl-pentamethylene 1 ,5-diisocyanate, 2-ethyl-butylene-1 ,4-diisocyanate, 1 ,5-pen- tamethylene diisocyanate (PDI), 1 ,4- butylene-diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclo- hexane (isophorone diisocyanate, IPDI), 1,4- bis(isocyanatomethyl)cyclohexane and / or 1,3-bis(isocyanatomethyl)cy- clohexane (HXDI), 2,4-paraphenylene diisocyanate (PPDI), 2,4-tetramethylene xylene diisocyanate (TMXDI), 4,4'-, 2,4'- and 2,2'-dicyclohexylmethane diisocyanate (H12MDI), 1 ,6-hexamethylene diisocyanate (HDI),1,4-cyclohexane diisocyanate, 1 -methyl-2,4- and / or -2,6-cyclohexane diisocyanate, 2,2'— diphenylmethane diisocyanate, 2,4'-diphenyl- methane diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 1 ,5-naphthylene diisocyanate (NDI), 2,4- toluene diisocyanate, 2,6-toluene diisocyanate (TDI), 3,3'-dimethyl-diphenyl diisocyanate, 1,2-diphenylethane diisocyanate and / or phenylene diisocyanate, or is a mixture thereof.

[0022] Preferably, the isocyanate is 2,2'- diphenylmethane, 2,4'- diphenylmethane or 4,4'-dipheny Imethane diisocyanate (MDI), or is a mixture thereof, especially preferred is 4,4'-diphenylmethane diisocyanate.

[0023] Suitable polyols are also known to the person skilled in the art. Preferably, the polyol, has on statistical average at least 1 .8 and at most 2.4 Zerewiti noff-active hydrogen atoms. This number is also referred to as the functionality of the polyol and indicates the quantity of the isocyanate-reactive groups of the molecule calculated theoretically down to one molecule from a quantity of substance. The functionality is preferred between 1 .8 and 2.2 and especially preferred 2. A polyol with the functionality of 2 is also referred to as polymer diol in the context of the present invention.

[0024] Preferably, the polyol has a number average molecular weight between 0.5 x103g / mol and 4 x103g / mol, more preferably between 0.6 x 103g / mol and 3.0 x 103g / mol, even more preferred between 0.8 x 103g / mol and 1.5 x 103g / mol.

[0025] Unless otherwise noted, the number average molecular weight Mn in the context of this invention preferably is determined by gel permeation chromatography, more preferably according to DIN EN ISO 13885-2:2020, no salt is used, instead of N,N-dimethylacetamide (DMAC), N,N-dimethylformamide (DMF) weight is determined at 60°C. 240882W001

[0026] - 4 -

[0027] Suitable polyols are for example polyesterpolyols, polyetherpolyols, polyesteretherpolyols or polycarbonate polyols. Preferably, the polyol is selected from the group consisting of polyether diol and polycarbonate diol. Particularly preferred the polyol is selected from polyether polyols.

[0028] Preferably, the polyol comprises a polyether diol, further preferred selected from the group of polyethanediol, poly- 1 ,3-propanediol and poly-1 , 4-butane diol and polytetrahydrofuran (PTHF).

[0029] Preferably, the polyetherpolyol, preferably the polytetrahydrofuran, has a number average molecular weight between 0.5 x 103g / Mol and 2 x 103g / Mol, more preferably between 0.6 x 103g / Mol and 1.5 x 103g / Mol, even more preferably between 0.8 x 103g / Mol and 1.2 x 103g / Mol, and most preferably 1.0 x 103g / Mol.

[0030] According to the present invention, the polyol may also comprise a polycarbonate diol, preferably an aliphatic polycarbonate diol. A preferred polycarbonate diol is a polycarbonate diol based on alkane diol. In a preferred embodiment the production of polycarbonate diol is carried out by polycondensation of phosgene with a diol or by ring-opening polymerization of cyclic carbonates, or by transesterification of a carbonic acid diester.

[0031] Preferably, the polycarbonate diol is an OH-difunctional polycarbonate diol, preferably an OH-difunctional aliphatic polycarbonate diol. A preferred polycarbonate diol is based on butanediol, pentanediol or hexanediol.

[0032] Preferably, the polycarbonate diol is based on 1 ,4-butanediol, 1 ,5-pentanediol, 1 ,6-hexanediol, and 3-methylpentane- (1 ,5)-diol, or a mixture thereof, more preferred the polycarbonate diol is based on 1 ,4-butanediol, 1 ,5-pentanediol, 1 ,6-hexanediol, or a mixture thereof.

[0033] Preferably, the polycarbonate diol is based on a mixture of 1 ,4-butanediol and 1 ,6-hexanediol, a mixture of 1 ,5-pen- tanediol and 1 ,6-hexanediol or is a polycarbonate diol based on 1 ,6-hexanediol or is a mixture thereof.

[0034] Preferably, the polycarbonate diol has a number average molecular weight Mn in the between 1 x 103and 5 x 103g / mol, more preferred between 1 .4 x 103g / mol and 3 x 103g / mol, more preferred between 1 .8 x 103g / mol and 2.2 x 103g / mol, more preferred 2.0 x 103g / mol.

[0035] Also, suitable chain extenders are in principle known to the person skilled in the art. Preferably, the chain extender is an aliphatic, araliphatic, aromatic, cycloaliphatic compound, or a mixture thereof, preferably with a molecular weight in the range of from 50 g / mol to 499 g / mol.

[0036] Preferably, the chain extender has 2 isocyanate-reactive functional groups. Preferred chain extenders are diamines and / or alkanediols. Further preferred the chain extender comprises 2 to 10 carbon atoms, more preferably 3 to 8 carbon atoms. The alkandiol preferably has only primary hydroxyl groups. 240882W001

[0037] - 5 -

[0038] Preferably, the chain extender is selected from 1 ,2-ethylene glycol, 1 ,3-propanediol, 1 ,4-butanediol, 1 ,6-hexanediol, hydroquinone bis (beta-hydroxyethyl) ether (HQEE) and di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona- or decaalkylene glycols, also preferred corresponding oligo- and / or polypropylene glycols or is a mixture thereof.

[0039] Preferably, the chain extender is selected from the group of 1 ,2-ethylene glycol, 1 ,3-propanediol, 1 ,4-butanediol, and 1 ,6-hexanediol, or is a mixture thereof, more preferred the chain extender is 1 ,3-propanediol, 1 ,4-butanediol, or a mixture thereof, most preferred the chain extender is 1 ,4-butanediol.

[0040] According to the present invention, the thermoplastic polyurethane (TPU-1) is present in composition (C1) in an amount in the range of from 75 to 98 % by weight, based on the weight of the composition (C1 ), in particular in the range of from 80 % by weight to 95 % by weight, most preferably in the range of from 85 % by weight to 92 % by weight.

[0041] Composition (C1) furthermore comprises a phosphorous containing additive (PA-1) selected from the group consisting of polyphosphonates and phosphoric acid esters.

[0042] According to one embodiment, composition (C1) comprises a polyphosphonate. Suitable polyphosphonates are in principle known to the person skilled in the art. Preferably, the polyphosphonate is an aromatic polyphosphonate, preferably the polyphosphonate preferably has a melting point between 100 °C and 115 °C, more preferably between 104 °C and 110 °C.

[0043] Preferably, the phosphorous content of the polyphosphate is in the range of from 5 weight-% to 20 weight-%, referring to the total amount of the polyphosphonate being 100 weight-%, particular in the range from 8 to 15 weight-%.

[0044] Preferably, the polyphosphonate comprises the structural element as outlined in Formula 1.

[0045] (Formula 1) wherein:

[0046] R is an organic rest with 0 to 20 carbon atoms, more preferably between 5 and 15 carbon atoms, more preferably the rest comprises an aromatic structure, more preferred R is a radical as outlined in Formula 2: 240882W001

[0047] - 6 -

[0048] Formula 2:

[0049] Preferably, the polyphosphonate is the polyphosphonate with the CAS-Number 68664-06-2.

[0050] According to a further embodiment, the present invention is also directed to a film as disclosed above, wherein the polyphosphonate is an aromatic polyphosphonate, more preferably the polyphosphonate comprises the following structure: wherein:

[0051] R is a rest with 0 to 20 carbon atoms, more preferably between 5 and 15 carbon atoms, more preferably the rest comprises an aromatic structure, most preferably R has the following structure:

[0052] Preferably, the structural element as outlined in Formula 1 is comprised in the polyphosphonate in an amount in the range of from 20 mol-% to 100 mol-%, referring to the total amount of polyphosphonate being 100 mol-%, more preferably 40 mol-% to 100 mol-%, more preferably from 60 mol-% to 100 mol-%, more preferably from 80 mol-% to 100 mol-%, more preferably from 90 mol-% to 100 mol-%.

[0053] Preferably, the weight average molecular weight of the polyphosphonate is between 3 x 103mol and 100 x 103mol, more preferably between 20 x 103mol and 80 x 103mol, more preferably between 40 x 103mol and 70 x 103mol, more preferably between 50 x 103mol and 60 x 103mol. 240882W001

[0054] According to a further embodiment, the present invention is also directed to a film as disclosed above, wherein the weight average molecular weight of the polyphosphonate is in the range of from 3 x 103mol to 100 x 103mol.

[0055] Typically, the amount of the polyphosphonate present in composition (C1) is limited to have good flame retardancy and good mechanical property of the film. It has been found that the phosphonate shows less migration to the surface of the film and enhances processability of the composition for extruding the film.

[0056] According to a further embodiment of the present invention, the phosphorous containing additive (PA-1) is selected from the group consisting of phosphoric acid esters. Suitable phosphoric acid esters are in principle known to the person skilled in the art.

[0057] Preferably, the phosphoric acid ester preferably is a tri-ester, more preferred a trialkyl phosphate or a triaryl phosphate, preferably triphenyl phosphate.

[0058] Preferably, the phosphoric ester has the general Formula 3:

[0059] Formula 3: where R denotes substituted alkyl, cycloalkyl, or phenyl groups, and n is an integer in the range from 1 to 15.

[0060] If R in the general formula (3) 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.

[0061] Preferably, n is 1 , or an integer from 3 to 6.

[0062] Preferably, the flame retardant is an aromatic phosphoric acid ester.

[0063] 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. 240882W001

[0064] - 8 -

[0065] Preferably, the flame retardant 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.

[0066] According to the present invention, it is also possible that composition (C1) comprises a mixture of two or more phosphorous containing additives (PA-1) selected from the group consisting of polyphosphonates and phosphoric acid esters. In this case, preferably the amount of the sum of components (PA-1) is in the range of from 2 to 25 % by weight, based on the weight of the composition (C1).

[0067] 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 phosphorous containing flame retardant (PA-2). The flame retardant may be a single substance or is a mixture of several substances.

[0068] 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-%.

[0069] Preferably, the additional 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.

[0070] According to a further embodiment, the present invention is also directed to a film as disclosed above, wherein the composition (C1) comprises a further additive (PA-2) in an amount of from 1 to 15 % by weight, based on the weight of the composition, wherein the additive (PA-2) is selected from the group consisting of flame retardants.

[0071] Preferably, the organic ester involves an alkyl ester, and in another preferred embodiment it involves an aryl ester, more preferred all of the hydroxy groups of the corresponding phosphorus-containing acid have been esterified.

[0072] According to a further embodiment, the present invention is also directed to a film as disclosed above, wherein the additive (PA-2) is selected from the group consisting of phosphoric acid esters.

[0073] According to the present invention, the phosphorous containing additive (PA-1) in present in composition (C1) in an amount in the range of from 2 to 25 % by weight, based on the weight of the composition (C1), in particular in the range of from 5 % by weight to 20 % by weight, most preferably in the range of from 8 % by weight to 15 % by weight.

[0074] Composition (C1) may also comprise further additives. The auxiliary or additive is a single substance, or a mixture of at least two substances. In a preferred embodiment the auxiliary or additive is selected from the group consisting of a 240882W001

[0075] - 9 - surface-active substance, a filler, a flame retardant, a nucleating agent, an oxidation stabilizer, a lubricating aid, a demolding aid, a dye, a pigment, an inorganic filler, an organic filler, a reinforcing agent, a plasticizer, an antistatic agent, a stabilizer, a wax, for example an amide based wax, preferably a stabilizer against hydrolysis, light, heat or discoloration, an inorganic filler, an organic filler, a reinforcing agent, a plasticizer, or is a mixture thereof.

[0076] A stabilizer preferably is an additive which protects a plastic or a plastic composition against harmful environmental influences. A preferred example is a primary or secondary antioxidant, a sterically hindered phenol, a hindered amine light stabilizer, an UV absorber, a phosphite, a hydrolysis inhibitor, a quencher, and a flame retardant, or is a mixture thereof. Examples of commercial stabilizers are given in Plastics Additives Handbook, 5th Edition, H. Zweifel, ed., Hanser Publishers, Munich, 2001 ([1]), p.98-S136.

[0077] Preferably the UV absorber has a number average molecular weight greater than 0.3 x 103g / Mol, in particular greater than 0.39 x 103g / Mol. Furthermore, the preferred UV absorber has a molecular weight not exceeding 5 x 103g / Mol, particularly preferred not exceeding 2 x 103g / mol.

[0078] The UV absorber is preferably selected from the group consisting of cinnamates, oxanilides, benzophenones and benzotriazole, or is a mixture thereof, particularly suitable as UV absorbers is benzotriazole. Examples of particularly suitable UV-absorbers are Tinuvin® 213, Tinuvin® 234, Tinuvin® 312, Tinuvin® 571, Tinuvin® 384 and Eversorb® 82.

[0079] Preferably the UV absorbers is added in quantities of 0.01 wt.% to 5 wt.% based on the total weight of the composition, preferably 0.1 wt.% to 2.0 wt.%, in particular 0.2 wt.% to 0.5 wt.%.

[0080] Often a UV stabilization based on an antioxidant and a UV absorber as described above is not sufficient to guarantee a good stability of the composition against the harmful influence of UV rays. In this case, in addition to the antioxidant and / or the UV absorber, or as single stabilizer, a hindered-amine light stabilizer (HALS) is added to the composition.

[0081] Examples of commercially available HALS stabilizers can be found in Plastics Additive Handbook, 5th edition, H. Zweifel, Hanser Publishers, Munich, 2001, pp. 123-136.

[0082] Particularly preferred hindered amine light stabilizers are bis-(1,2,2,6,6-penta_|methylpiperidyl) sebacat (Tinuvin® 765, Ciba Spezialitatenchemie AG) and the condensation product of 1 -hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypi- peridine and succinic acid (Tinuvin® 622). In particular, the condensation product of 1 -hydroxyethyl-2,2,6,6-tetrame- thyl-4-hydroxypiperidines and succinic acid (Tinuvin® 622) is preferred, if the titanium content of the finished product is less than 150 ppm by weight, preferably less than 50 ppm by weight, in particular less than 10 ppm by weight, based on the components used.

[0083] HALS compounds are preferably used in a concentration of from 0.01 wt.% to 5 wt.%, particularly preferably from 0.1 wt.% to 1 wt.%, in particular from 0.15 wt.% to 0.3 wt.%, based on the total weight of the composition. 240882W001

[0084] - 10 -

[0085] A particularly preferred UV stabilizer contains a mixture of a phenolic stabilizer, a benzotriazole and a HALS compound in the preferred amounts described above.

[0086] In case a wax is added, suitable amounts are for example in the range of from 0.001 wt.% to 0.1 wt.%, particularly preferably from 0.01 wt.% to 0.1 wt.%, based on the total weight of the composition. Preferably, an amide based wax is added in an amount in the range of from 0.001 wt.% to 0.1 wt.%, particularly preferably from 0.01 wt.% to 0.1 wt.%, based on the total weight of the composition

[0087] Further information on the above-mentioned auxiliaries and additives can be found in the technical literature, e.g. Plastics Additives Handbook, 5th edition, H. Zweifel, ed., Hanser Publishers, Munich, 2001, p. 123-136.

[0088] The film according to the present invention comprises composition (C1) and may also comprise further components such as for example fillers, fibers or mats. Furthermore, the film may also comprise layers. In case the film comprises layers, preferably one of the layers comprises composition (C1). According to a further embodiment, the present invention is also directed to a film as disclosed above, wherein the film comprises at least one filler.

[0089] The films according to the present invention are suitable for a wide range of applications. They are for example suitable for the application as adhesives. Adhesives with good mechanical properties and flame retardancy are needed for many applications. In particular for applications in the automobile industry or for consumer goods, it is advantageous that the films are odor free.

[0090] It has been found that the films according to the present invention are particularly suitable as adhesive films, in particular for articles for the automobile industry, for machine construction, for consumer goods, batteries, or articles for e-mobility. According to a further embodiment, the present invention is also directed to a film as disclosed above, wherein the film is an adhesive film, preferably for articles for the automobile industry, for machine construction, for consumer goods, batteries, or articles for e-mobility.

[0091] The film according to the present invention may also comprise further components such as for example fibers or fillers. The fibers or filler may also be embedded within the film, for example composition (C1) may form a film and the fibers or filler is embedded therein. Suitable fillers or fibers are in principle known and may for example be present in form of woven or non-woven fibers.

[0092] The film may also be used in a multi-layer composition, for example in combination with a layer (LP) comprising a polymer selected from polyethylene terepthalate, polyurethane, polyamide, polybutylene terephthalate or ABS copoylmers. The additional layer may also comprise a filler, preferably a fibrous filler which may also be a mat comprising fibers, in particular mineral fibers. According to a further embodiment, the present invention is also directed to 240882W001

[0093] - 11 - a composite comprising a film as disclosed above and a further layer (LP), wherein the layer (LP) comprises at least one mat comprising mineral fibers.

[0094] According to a further aspect, the present invention is also directed to the use of a film as disclosed above for bonding a first part and a second part.

[0095] Bonding is preferably achieved by physical softening the adhesive film at elevated temperatures and re-solidification on cooling according to the present invention.

[0096] The parts may comprise different materials and may also vary in shape and size. According to the present invention, it is also possible that the at least two parts comprise the same material. At least two parts are bonded to form an article. According to the present invention, the article may also comprise further parts or components.

[0097] The first part or component of the bonded article may comprise a polymer, a metal, leather, wood, a ceramic material, a textile material, glass, rubber, cement, minerals, for example a crepe rubber, a natural leather, a synthetic leather, a polyurethane (for example a polyurethane foam and / or a thermoplastic polyurethane TPU), a thermoplastic rubber, a styrene butadiene rubber, a polyvinyl acetate, a polyamide (PA), a polyvinyl chloride, a polystyrene, an acrylonitrile butadiene styrene, a polyethylene terephthalate (PET), a polybutylene terephthalate, a textile, a fabric, a thermo-plastic polyurethane knit fiber and a combination thereof. The second part or component may comprise the same or a different material.

[0098] The film according to the present invention may be applied to a surface, in particular a surface of the first part and the second part may be applied to the second surface of the film.

[0099] 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.

[0100] 1. Film comprising a composition (C1) comprising a thermoplastic polyurethane (TPU-1) in an amount in the range of from 75 to 98 % by weight, and a phosphorous containing additive (PA-1) in an amount in the range of from 2 to 25 % by weight, based on the weight of the composition (C1), 240882W001

[0101] - 12 - wherein the phosphorous containing additive (PA-1) is selected from the group consisting of polyphospho- nates and phosphoric acid esters.

[0102] 2. The film according to embodiment 1, wherein the composition (C1) is free of siloxane polymers.

[0103] 3. The film according to embodiment 1 or 2, wherein the weight average molecular weight of the polyphospho- nate is in the range of from 3 x 103mol to 100 x 103mol.

[0104] 4. The film according to any one of embodiments 1 to 3, wherein the polyphosphonate is an aromatic polyphos- phonate, more preferably the polyphosphonate comprises the following structure: wherein:

[0105] R is a rest with 0 to 20 carbon atoms, more preferably between 5 and 15 carbon atoms, more preferably the rest comprises an aromatic structure, most preferably R has the following structure:

[0106] 5. Film comprising a composition (C1) comprising a thermoplastic polyurethane (TPU-1) in an amount in the range of from 75 to 98 % by weight, and a phosphorous containing additive (PA-1) in an amount in the range of from 2 to 25 % by weight, based on the weight of the composition (C 1 ), wherein the phosphorous containing additive (PA-1) is selected from the group consisting of polyphospho- nates and phosphoric acid esters; and wherein the polyphosphonate is an aromatic polyphosphonate, more preferably the polyphosphonate comprises the following structure: 240882W001 wherein:

[0107] R is a rest with 0 to 20 carbon atoms, more preferably between 5 and 15 carbon atoms, more preferably the rest comprises an aromatic structure, most preferably R has the following structure:

[0108] 6. The film according to any one of embodiments 1 to 5, wherein the composition (C1) comprises a further additive (PA-2) in an amount of from 1 to 15 % by weight, based on the weight of the composition, wherein the additive (PA-2) is selected from the group consisting of flame retardants.

[0109] 7. Film comprising a composition (C1) comprising a thermoplastic polyurethane (TPU-1) in an amount in the range of from 75 to 98 % by weight, and a phosphorous containing additive (PA-1) in an amount in the range of from 2 to 25 % by weight, based on the weight of the composition (C 1 ), wherein the phosphorous containing additive (PA-1) is selected from the group consisting of polyphospho- nates and phosphoric acid esters; and wherein the composition (C1) comprises a further additive (PA-2) in an amount of from 1 to 15 % by weight, based on the weight of the composition, wherein the additive (PA-2) is selected from the group consisting of flame retardants.

[0110] 8. The film according to any one of embodiments 1 to 7, wherein the additive (PA-2) is selected from the group consisting of phosphoric acid esters.

[0111] 9. The film according to any one of embodiments 1 to 8, wherein the film is an adhesive film, preferably for articles for the automobile industry, for machine construction, for consumer goods, batteries, or articles for e-mo- bility.

[0112] 10. The film according to any one of embodiments 1 to 9, wherein the film comprises at least one filler. 240882W001

[0113] - 14 -

[0114] 11 . The film according to any one of embodiments 1 to 8, wherein the film is part of a multi-layer composite comprising a layer (LP) which comprises at least one mat comprising mineral fibers.

[0115] 12. Film comprising a composition (C1) comprising a thermoplastic polyurethane (TPU-1) in an amount in the range of from 75 to 98 % by weight, and a phosphorous containing additive (PA-1) in an amount in the range of from 2 to 25 % by weight, based on the weight of the composition (C 1 ), wherein the phosphorous containing additive (PA-1) is selected from the group consisting of polyphospho- nates and phosphoric acid esters; wherein the composition (C1) comprises a further additive (PA-2) in an amount of from 1 to 15 % by weight, based on the weight of the composition, wherein the additive (PA-2) is selected from the group consisting of flame retardants, wherein the additive (PA-2) is selected from the group consisting of phosphoric acid esters; and wherein the film is part of a multi-layer composite comprising a layer (LP) which comprises at least one mat comprising mineral fibers.

[0116] 13. Use of a film according to any one of embodiments 1 to 12 for bonding a first part and a second part.

[0117] 14. Use of a film for bonding a first part and a second part, the film comprising a composition (C1) comprising a thermoplastic polyurethane (TPU-1) in an amount in the range of from 75 to 98 % by weight, and a phosphorous containing additive (PA-1) in an amount in the range of from 2 to 25 % by weight, based on the weight of the composition (C1), wherein the phosphorous containing additive (PA-1) is selected from the group consisting of polyphospho- nates and phosphoric acid esters.

[0118] 15. The use according to embodiment 14, wherein the composition (C1) is free of siloxane polymers.

[0119] 16. The use according to embodiment 14 or 15, wherein the weight average molecular weight of the polyphos- phonate is in the range of from 3 x 103mol to 100 x 103mol.

[0120] 17. The use according to any one of embodiments 14 to 16, wherein the polyphosphonate is an aromatic poly- phosphonate, more preferably the polyphosphonate comprises the following structure: 240882W001 wherein:

[0121] R is a rest with 0 to 20 carbon atoms, more preferably between 5 and 15 carbon atoms, more preferably the rest comprises an aromatic structure, most preferably R has the following structure:

[0122] 18. The use according to any one of embodiments 14 to 17, wherein the composition (C1) comprises a further additive (PA-2) in an amount of from 1 to 15 % by weight, based on the weight of the composition, wherein the additive (PA-2) is selected from the group consisting of flame retardants.

[0123] 19. The use according to any one of embodiments 14 to 18, wherein the additive (PA-2) is selected from the group consisting of phosphoric acid esters.

[0124] 20. The use according to any one of embodiments 14 to 18, wherein the film is an adhesive film, preferably for articles for the automobile industry, for machine construction, for consumer goods, batteries, or articles for e- mobility.

[0125] 21. The use according to any one of embodiments 14 to 20, wherein the film comprises at least one filler.

[0126] 22. The use according to any one of embodiments 14 to 21, wherein the film is part of a multi-layer composite comprising a layer (LP) which comprises at least one mat comprising mineral fibers.

[0127] 23. A process for bonding a first part and a second part, comprising applying a film according to any one of embodiments 1 to 12 to the first part or the second part or the first and the second part and joining the first part and the second part. 240882W001

[0128] - 16 -

[0129] 24. A process for bonding a first part and a second part, comprising applying a film to the first part or the second part or the first and the second part and joining the first part and the second part, the film comprising a composition (C1) comprising a thermoplastic polyurethane (TPU-1) in an amount in the range of from 75 to 98 % by weight, and a phosphorous containing additive (PA-1) in an amount in the range of from 2 to 25 % by weight, based on the weight of the composition (C1), wherein the phosphorous containing additive (PA-1) is selected from the group consisting of polyphospho- nates and phosphoric acid esters.

[0130] 25. The process according to embodiment 24, wherein the composition (C 1 ) is free of siloxane polymers.

[0131] 26. The process according to embodiment 24 or 25, wherein the weight average molecular weight of the poly- phosphonate is in the range of from 3 x 103mol to 100 x 103mol.

[0132] 27. The process according to any one of embodiments 24 to 26, wherein the polyphosphonate is an aromatic polyphosphonate, more preferably the polyphosphonate comprises the following structure: wherein:

[0133] R is a rest with 0 to 20 carbon atoms, more preferably between 5 and 15 carbon atoms, more preferably the rest comprises an aromatic structure, most preferably R has the following structure:

[0134] 28. The process according to any one of embodiments 24 to 27, wherein the composition (C1) comprises a further additive (PA-2) in an amount of from 1 to 15 % by weight, based on the weight of the composition, wherein the additive (PA-2) is selected from the group consisting of flame retardants.

[0135] 29. The process according to any one of embodiments 24 to 28, wherein the additive (PA-2) is selected from the group consisting of phosphoric acid esters. 240882W001

[0136] - 17 -

[0137] 30. The process according to any one of embodiments 24 to 28, wherein the film is an adhesive film, preferably for articles for the automobile industry, for machine construction, for consumer goods, batteries, or articles for e-mobility.

[0138] 31 . The process according to any one of embodiments 24 to 30, wherein the film comprises at least one filler.

[0139] 32. The process according to any one of embodiments 24 to 31 , wherein the film is part of a multi-layer composite comprising a layer (LP) which comprises at least one mat comprising mineral fibers.

[0140] 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 claims of the present invention.

[0141] The present invention is further illustrated by the following examples.

[0142] Examples:

[0143] 1 . Example 1 - Materials used:

[0144] TPU1 : TPU of Shore hardness 85A from BASF Polyurethanes GmbH, Elastogranstrasse

[0145] 60, 49448 Lemfoerde, is based on polytetrahydrofuran polyol (PTHF) with a molecular weight of 1000 g / mol, 1 ,4-butanediol and diphenylmethane-4,4’-diisocya- nate.

[0146] Nofia HM 1100: Polyphosphonate homopolymer, CAS#: 68664-06-2, FRX Polymers (Europe),

[0147] 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).

[0148] 2. Example 2:

[0149] The following table 1 lists compositions A and B for which the individual material used are given in terms of weight fractions (WF). The compositions were each produced with a twin-shaft extruder type ZE 40 A from KrausMaffei Berstorff GmbH, Germany, with a travel part length of 35 D divided into 10 housings. The compositions were granulated by means of a standard underwater granulation of the company Gala (UWG). 240882W001

[0150] - 18 -

[0151] 3. Example 3

[0152] For studying the mechanical properties of the compositions granulated compositions of Example 2 were extruded into films with a thickness of 1 .6 mm in a single-shaft extruder, from company Arenz GmbH, in Ger- many with a three-zone snout with a mixing part (screw ratio 1 :3). The density, shore hardness, tensile strength, tear propagation resistance, abrasion, and elongation at break of the extruded films were measured. The results are summarized in the table below.

[0153] Table 1 :

[0154] 10

[0155] CE: comparative example

[0156] IE: example according to the invention 4. Example 4

[0157] For the cone measurements the granulated composition from Example 2 were injection molded on an extruder (Arburg 520S) with a screw diameter of 30 mm into plates with a dimension of 200x150x5mm. The plates were then sawn to the size required for the test specimens for the cone measurement (100x100x5mm).

[0158] In order to evaluate the flame retardancy, a test specimen is tested horizontally at a radiation intensity of 35kW / m2in the cone calorimeter according to ISO 5660 Part 1 and Part 2 (2002-12). 240882W001

[0159] - 19 -

[0160] The results are summarized in Table 2. For composition B versus composition A, the total heat evolved (THE) and the peak of heat release (PHRR) have been significantly reduced.

[0161] Table 2:

[0162] Literature cited:

[0163] EP 1323800 A1 Plastics Additives Handbook, 5th Edition, H. Zweifel, ed., Hanser Publishers, Munich, 2001 ([1]), p.98-136.

Claims

240882W001- 20 -Claims1. Film comprising a composition (C1) comprising a thermoplastic polyurethane (TPU-1) in an amount in the range of from 75 to 98 % by weight, and a phosphorous containing additive (PA-1) in an amount in the range of from 2 to 25 % by weight, based on the weight of the composition (C1 ), wherein the phosphorous containing additive (PA-1) is selected from the group consisting of polyphospho- nates and phosphoric acid esters.

2. The film according to claim 1 , wherein the composition (C1) is free of siloxane polymers.

3. The film according to claim 1 or 2, wherein the weight average molecular weight of the polyphosphonate is in the range of from 3 x 103mol to 100 x 103mol.

4. The film according to any one of claims 1 to 3, wherein the polyphosphonate is an aromatic polyphospho- nate, more preferably the polyphosphonate comprises the following structure:wherein:R is a rest with 0 to 20 carbon atoms, more preferably between 5 and 15 carbon atoms, more preferably the rest comprises an aromatic structure, most preferably R has the following structure:

5. The film according to any one of claims 1 to 4, wherein the composition (C1) comprises a further additive (PA- 2) in an amount of from 1 to 15 % by weight, based on the weight of the composition, wherein the additive (PA-2) is selected from the group consisting of flame retardants.

6. The film according to any one of claims 1 to 4, wherein the additive (PA-2) is selected from the group consisting of phosphoric acid esters.240882W001- 21 -7. The film according to any one of claims 1 to 6, wherein the film is an adhesive film, preferably for articles for the automobile industry, for machine construction, for consumer goods, batteries, or articles for e-mobility.

8. The film according to any one of claims 1 to 7, wherein the film comprises at least one filler.

9. The film according to any one of claims 1 to 8, wherein the film is part of a multi-layer composite comprising a layer (LP) which comprises at least one mat comprising mineral fibers.

10. Use of a film according to any one of claims 1 to 9 for bonding a first part and a second part.

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