Paint protection film formed from aliphatic thermoplastic polyurethane

Abstract

The present disclosure relates to paint protection films and a method of preparing the paint protection films. The paint protection films comprise a thermoplastic polyurethane film which is made from one or more thermoplastic polyurethanes, specifically aliphatic thermoplastic polyurethane. PCL and polyether polyols are used in the production of the films.

Description

1 EU-51184PAINT PROTECTION FILM FORMED FROM ALIPHATIC THERMOPLASTIC POLYURETHANE CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to US Provisional Application 63 / 769,476 filed March 10, 2025, the contents of which are incorporated herein by reference.FIELD OF INVENTION

[0002] The present disclosure relates to paint protection films and a method of preparing the paint protection films. The paint protection films comprise a thermoplastic polyurethane film which is made from one or more thermoplastic polyurethanes, specifically aliphatic thermoplastic polyurethane.BACKGROUND

[0003] Paint protection films (PPFs) are widely used in many industries, such as the automotive industry. The general purpose of a paint protection film (PPF) is to protect a painted surface from the external environment. For instance, a PPF may be applied to a painted automotive part in order to protect the paint from stone chips, bug splatters and minor abrasions.

[0004] PPFs need to have high transparency so as not to affect the aesthetics of the object to which they are applied. Moreover, the PPF needs to have good mechanical properties; good elasticity; good chemical / solvent resistance towards denatured alcohol, gasoline and lubricant oil; good hydrolytic stability; and good weathering aging performance. All of these properties are important for a PPF to function effectively, and an effective balance of these properties is required for a PPF to be commercially viable.

[0005] Currently, a premium grade aliphatic thermoplastic polyurethane (TPU), which is derived from an aliphatic polyisocyanate component (H12MDI) and a polyol component consisting of polycaprolactone (PCL), is commercially available for premium PPFs. However, PCL is expensive, and for a more cost-effective approach, it would be desirable to at least partially replace PCL with another polyol when forming the aliphatic TPU. However, when replacing the PCL with another polyol, it is essential the PPF retains a good balance of properties such as high transparency, good mechanical properties, good elasticity, good chemical / solvent resistance, good hydrolytic stability and good weathering aging performance.2 EU-51184

[0006] Thus, there is a need for a PPF (formed from an aliphatic TPU) which is more commercially viable than the premium grade PPF (by replacement of PCL) and which retains a good balance of properties such as high transparency, good mechanical properties, good elasticity, good chemical / solvent resistance, good hydrolytic stability and good weathering aging performance.

[0007] The present disclosure addresses the problems and needs mentioned above. Specifically, the present inventors have surprisingly found that an aliphatic TPU derived from H12MDI and a polyol component comprising a mixture of a poly ether polyol and PCL retains a good balance of properties in the PPF. That is, some PCL may be replaced by a polyether polyol in the aliphatic TPU used to form the PPF without adversely affecting the properties of the TPU, which ultimately makes the PPF more commercially viable. Moreover, the present inventors have surprisingly found that a PPF comprising the aliphatic TPU described herein has superior resistance to gasoline in terms of reduced shrinkage when exposed to gasoline compared to the premium grade PPF. This is particularly useful given that cars and car parts are often exposed to gasoline or at risk of gasoline exposure.SUMMARY

[0008] In a first aspect, there is provided a paint protection film (PPF) comprising a thermoplastic polyurethane film, wherein the thermoplastic polyurethane film is formed from a thermoplastic polyurethane, wherein the thermoplastic polyurethane is obtained from a polyurethane formulation comprising the following components:i) 4,4'-diisocyanatodicyclohexylmethane (H12MDI) or prepolymer thereof; ii) a polyether polyol compound;iii) a polycaprolactone compound (PCL); andiv) a chain extender compound.

[0009] Such a PPF is termed herein a “chemical blend PPF” due to the PCL and polyether compound being chemically blended and integrated into the same thermoplastic polyurethane. Such a PPF has a good balance of properties such as high transparency, good mechanical properties, good elasticity, good chemical / solvent resistance, good hydrolytic stability and good weathering aging performance. Moreover, such a PPF is economical due to the replacement of some expensive PCL, compared to the premium PPFs available.3 EU-51184

[0010] In a second aspect, there is provided a paint protection film comprising a thermoplastic polyurethane film, wherein the thermoplastic polyurethane film is formed from a blend of a first thermoplastic polyurethane and a second thermoplastic polyurethane, wherein the first thermoplastic polyurethane is obtained from a first polyurethane formulation comprising:i) 4,4'-diisocyanatodicyclohexylmethane (H12MDI) or prepolymer thereof; ii) a polyether polyol compound; andiii) a chain extender compound,and the second thermoplastic polyurethane is obtained from a second polyurethane formulation comprising:i) 4,4'-diisocyanatodicyclohexylmethane (H12MDI) or prepolymer thereof; ii) a polycaprolactone compound; andiii) a chain extender compound.

[0011] Such a PPF is termed herein a “physical blend PPF” due to the poly ether compound and PCL compound being integrated into different thermoplastic polyurethanes (termed herein “first thermoplastic polyurethane” and “second thermoplastic polyurethane” respectively), wherein the different thermoplastic polyurethanes are then physically blended before / during the formation of the film. Such a PPF has a good balance of properties such as high transparency, good mechanical properties, good elasticity, good chemical / solvent resistance, good hydrolytic stability and good weathering aging performance. Moreover, such a PPF is economical due to the replacement of some expensive PCL-containing polyurethane with polyether-containing polyurethane, compared to the premium PPFs available.

[0012] In a third aspect, there is provided a method of preparing a paint protection film comprising the following steps: step a) providing a thermoplastic polyurethane as defined herein or a blend of a first thermoplastic polyurethane and a second thermoplastic polyurethane as defined herein; and step b) forming a thermoplastic polyurethane film from the thermoplastic polyurethane.

[0013] The embodiments described should not be read to limit or otherwise narrow the scope of any inventive concepts otherwise provided by the present disclosure. While multiple embodiments are disclosed, other embodiments will become apparent to those skilled in the art from the following description. Accordingly, the description is to be regarded as illustrative rather than restrictive.4 EU-51184DETAILED DESCRIPTION

[0014] PPFs may be applied to painted objects to protect the object from an external environment. For example, PPFs may be applied to painted automobile parts to protect the paint work. PPFs typically comprise a plastic film, an adhesive layer and a top layer. In one embodiment, the PPF described herein comprises a thermoplastic polyurethane film as described herein, an adhesive layer and a top layer. Further layers may also be present, if needed or desired.

[0015] The present disclosure provides a PPF comprising a thermoplastic polyurethane film.As used herein, the terms “first”, “second”, “third” etc. preceding an object (such as first thermoplastic polyurethane) distinguishes that object from another object having a different preceding term (such as second thermoplastic polyurethane). In other words, a first thermoplastic polyurethane is different from a second thermoplastic polyurethane.

[0016] [Thermoplastic polyurethane film (chemical blend)]

[0017] In one aspect, the thermoplastic polyurethane film is formed from a thermoplastic polyurethane obtained from a polyurethane formulation comprising the following components:i) 4,4'-diisocyanatodicyclohexylmethane (H12MDI) or prepolymer thereof; ii) a poly ether polyol compound;iii) a polycaprolactone compound (PCL); andiv) a chain extender compound.

[0018] The form of the thermoplastic polyurethane is not particularly limited and may be pellets, granules, flakes or beads.

[0019] The thermoplastic polyurethane is obtained from a polyurethane formulation. In particular, the thermoplastic polyurethane is obtained from reacting the components of the polyurethane formulation.

[0020] The polyurethane formulation comprises the following components:i) 4,4'-diisocyanatodicyclohexylmethane (H12MDI) or prepolymer thereof; ii) a polyether polyol compound;iii) a polycaprolactone compound (PCL); andiv) a chain extender compound.

[0021] Further components may be present, such as surfactants, catalysts, antioxidants, UV additives, flame retardants and the like.

[0022] 4,4'-diisocyanatodicyclohexylmethane (H12MDI) is also termed “hydrogenated MDI” in the art and is readily commercially available. H12MDI has the following structure:5 EU-51184

[0023] In one embodiment, the average NCO value of the H12MDI is from 20 to 40%, or from 30 to 40%.

[0024] The H12MDI prepolymer may be prepared by reaction of an excessive amount of H12MDI with a suitable polyfunctional polyol in order to obtain a prepolymer having a desired NCO value. The polyfunctional polyol may be the same as the polyether polyol compound used in the polyurethane formulation, or may be different but independently selected from the polyether polyol compounds defined below. Any suitable polyfunctional polyol may be used. Methods to prepare prepolymers have been described in the art. The relative amounts of H12MDI and polyfunctional polyol depend on their equivalent weights and on the desired NCO value and can be determined easily by those skilled in the art. The NCO value of the prepolymer is above 3%, or above 5%, or above 8%, or above 10%. The NCO value of the prepolymer may be from 3% to 40%, or from 5% to 25%.

[0025] In one embodiment, the polyurethane formulation may comprise from 20 weight% to 60 weight%, or from 25 weight% to 55 weight%, or from 30 weight% to 50 weight%, or from 35 weight% to 45 weight%, of H12MDI, based upon the total weight of the polyurethane formulation.

[0026] In one embodiment, the polyurethane formulation may comprise from 50 weight% to 95 weight%, or from 60 weight% to 95 weight%, or from 70 weight% to 90 weight%, or from 85 weight% to 90 weight%, of H12MDI prepolymer, based upon the total weight of the polyurethane formulation.

[0027] In one embodiment, the polyurethane formulation does not contain any further polyisocyanate compounds besides H12MDI.

[0028] The polyether polyol compound (component (ii)) used herein is not particularly limited and any suitable polyether polyol compound in the art may be used.

[0029] Examples of polyether polyol compounds include, but are not limited to, polyethylene glycol, polypropylene glycol, polypropylene glycol-ethylene glycol copolymer, polytetrahydrofuran polyol (pTHF or PTMEG), polytetramethylene glycol, polyhexamethylene glycol, polyheptamethylene glycol, polydecamethylene glycol, and polyether polyols obtained by ring-opening co-polymerization of alkylene oxides, such6 EU-51184as ethylene oxide and / or propylene oxide and / or butylene oxide, with isocyanatereactive initiators having functionality from 2 to 8.

[0030] The poly ether polyol compound may be made by the addition of alkylene oxides to initiators, which may contain from 2 to 8 active hydrogen atoms per molecule. In some embodiments, the initiators may include glycols, glycerol, trimethylolpropane, triethanolamine, pentaerythritol, sorbitol, sucrose, ethylenediamine, ethanolamine, diethanolamine, aniline, toluenediamines (e.g., 2,4- and 2,6- toluenediamines), polymethylene polyphenylene polyamines, N-alkylphenylene-diamines, o-chloro- aniline, p-aminoaniline, diaminonaphthalene, or a combination thereof. Suitable alkylene oxides that may be used to form the polyether polyol compounds include ethylene oxide (EO), propylene oxide (PO), butylene oxide, or a combination thereof. In one embodiment, the polyether polyol compound is an alkylene oxide-based poly ether compound. In one embodiment, the poly ether polyol compound is an alkylene oxide-based poly ether compound having a hydroxyl functionality of 2 or 3.

[0031] When the alkylene oxide used to form the poly ether polyol compound is EO and / or PO, the poly ether polyol may comprise PO, EO, or a combination of PO and EO groups or moieties in the polymeric structure. These PO and EO units may be arranged randomly or in block sections throughout the polymeric structure. In some embodiments, the EO content of the polyol may range from 0 to 100% by weight based on the total weight of the polyol. In some embodiments, the PO content of the polyol may range from 100 to 0% by weight based on the total weight of the polyol. In some embodiments, the EO content of a polyol can range from 1% to 99% by weight of the polyol while the PO content can range from 99% to 1% by weight of the polyol. Often the EO content of a polyol can range from 5% to 80% by weight of the polyol, or from 5% to 30% by weight of the polyol. On the other hand, the PO content can range from 20% to 95% by weight of the polyol, or from 70 to 95% of the polyol. Moreover, in some embodiments, the EO and / or PO units can either be located terminally on the polymeric structure of the polyol or within the interior sections of the polymeric backbone structure of the polyol. Suitable polyether polyols include poly(oxyethylene oxypropylene) diols obtained by the sequential addition of PO and EO to initiators that are known in the art.

[0032] In one embodiment, the polyether polyol compound is any one selected from a polytetrahydrofuran polyol (pTHF or PTMEG), an alkylene oxide-based polyether compound such as an ethylene oxide- and / or propylene oxide-based polyether polyol,7 EU-51184and a combination thereof. In one embodiment, the polyether polyol compound is an ethylene oxide- and / or propylene oxide-based polyether polyol.

[0033] In a preferred embodiment, the polyether polyol compound is a polytetrahydrofuran polyol (pTHF or PTMEG). pTHF may be produced by polymerisation of tetrahydrofuran (THF). Alternatively, pTHF may be produced from butanediol.

[0034] In one embodiment, the polyether polyol compound has an average hydroxyl number (OHv) of from 10 to 500 mg KOH / g, or from 20 to 250 mg KOH / g, or from 50 to 150 mg KOH / g, or from 80 to 140 mg KOH / g. Herein, the average hydroxyl number (OHv) is determined according to ASTM E222-17.

[0035] In one embodiment, the poly ether polyol compound has a theoretical hydroxyl functionality of 1 to 3, or preferably 2. As used herein, “theoretical functionality” refers to the expected functionality based upon the reactants used to produce the polyol, assuming no side reactions. For example, glycerol-initiated EO polyol has a theoretical functionality of 3, and pTHF has a theoretical functionality of 2.

[0036] In one embodiment, the poly ether polyol compound has a weight average molecular weight of from 500 g / mol to 10,000 g / mol, or from 500 g / mol to 5000 g / mol, or from 500 g / mol to 2500 g / mol, or from 500 g / mol to 2000 g / mol, or from 500 g / mol to 1500 g / mol. Herein, the weight average molecular weight of a polyol may be measured be gel permeation chromatography (GPC).

[0037] The poly ether polyol compound may contain one type of compound, or two types of compound, or three types of compound, and so on. In one embodiment, the polyether polyol compound contains only one or two types of polyether polyol compound, preferably only one type of polyether polyol compound. As used herein, “type” of compound refers to compounds sharing similar / same general structures, e.g. two pTHF compounds of different molar mass are the same type of compound whereas a pTHF compound and an EO- and / or PO-based polyether polyol are different types of compound.

[0038] In one embodiment, the polyurethane formulation may comprise from 5 weight% to 65 weight%, or from 10 weight% to 60 weight%, or from 10 weight% to 55 weight%, or from 15 weight% to 50 weight%, or from 20 weight% to 45 weight%, or from 20 weight% to 40 weight%, of the polyether polyol compound, based upon the total weight of the polyurethane formulation.

[0039] The polyurethane formulation comprises a polycaprolactone compound (PCL) (component (iii)). PCL may be prepared by the ring opening polymerization of8 EU-51184caprolactone using a functional initiator molecule, optionally in the presence of a catalyst. PCL compounds are readily commercially available.

[0040] Suitable initiator molecules include, but are not limited to, diol compounds. Specific examples include 1,6-hexanediol, 1,4-butanediol, monoethylene glycol, di ethylene glycol, triethyleneglycol, tetraethyleneglycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propanediol, 1,-3 -butanediol, 1,5-pentanediol, poly caprolactone diol, 2-m ethyl- 1,3 -propanediol, neopentyl glycol, 1,4- cyclohexanedimethanol, hydroquinone bis (2-hydroxyethyl) ether (HQEE), 1,3-bis (2- hydroxyethyl) resorcinol (HER), ethanolamine, methyldiethanolamine, phenyldiethanolamine, and any combinations thereof.

[0041] In one embodiment, the PCL compound is obtained by reacting caprolactone with any one of monoethylene glycol, diethylene glycol and neopentyl glycol as the initiator. In one embodiment, the PCL compound is obtained by reacting caprolactone with any one of diethylene glycol and neopentyl glycol as the initiator. In one embodiment, the PCL compound is obtained by reacting caprolactone with diethylene glycol as the initiator.

[0042] In one embodiment, the PCL compound has a theoretical functionality of from 1 to 3, preferably 2.

[0043] In one embodiment, the PCL compound has a weight average molecular weight of from 500 g / mol to 10,000 g / mol, or from 500 g / mol to 5000 g / mol, or from 500 g / mol to 2500 g / mol, or from 500 g / mol to 2000 g / mol, or from 750 g / mol to 1500 g / mol. Herein, the weight average molecular weight of a polyol may be measured be gel permeation chromatography (GPC).

[0044] In one embodiment, the PCL compound has an average hydroxyl number (OHv) of from 20 to 500 mg KOH / g, or from 40 to 200 mg KOH / g, or from 50 to 150 mg KOH / g. Herein, the average hydroxyl number (OHv) is determined according to ASTM E222- 17.

[0045] In one embodiment, the polyurethane formulation may comprise from 2 weight% to 65 weight%, or from 5 weight% to 60 weight%, or from 5 weight% to 50 weight%, or from 5 weight% to 40 weight%, or from 5 weight% to 30 weight%, or from 5 weight% to 20 weight%, of the PCL compound, based upon the total weight of the polyurethane formulation.

[0046] In one embodiment, the weight ratio of the polyether polyol compound to the polycaprolactone compound in the polyurethane formulation is from 20:1 to 1:10, or9 EU-51184from 15:1 to 1:4, or from 10:1 to 1:4, or from 10:1 to 1:2, or from 5:1 to 1:1, or from 4:1 to 1:1, or from 4:1 to 2:1.

[0047] According to an embodiment, the chain extender compound (component (iv)) may comprise one or more types of chain extender compounds each having a molar mass of less than 500 g / mol, or from 16 g / mol to 500 g / mol, or from 16 g / mol to 250 g / mol. A chain extender is typically a diol compound. In one embodiment, the chain extender compound is independently any one selected from water, 1,6-hexanediol, 1,4-butanediol, monoethylene glycol, diethylene glycol, triethyleneglycol, tetraethyleneglycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3 -propanediol, 1,-3- butanediol, 1,5-pentanediol, methylpentanediol, polycaprolactone diol, 2-methyl-l,3- propanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, hydroquinone bis (2- hydroxy ethyl) ether (HQEE), 1 ,3 -bis (2 -hydroxy ethyl) resorcinol (HER), ethanolamine, methyldiethanolamine, phenyldiethanolamine, and any combinations thereof. In a preferred embodiment, the chain extender compound is any one selected from ethylene glycol, di ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, methylpentanediol, 1,6-hexanediol, dipropylene glycol, tripropylene glycol and a combination thereof. In a more preferred embodiment, the chain extender compound is any one selected from 1,6-hexanediol, 1,4-butanediol, di ethylene glycol and ethylene glycol, and is preferably 1,4-butanediol.

[0048] In one embodiment, the polyurethane formulation may comprise from 2 weight% to 20 weight%, or from 5 weight% to 15 weight%, or from 7 weight% to 13 weight%, of the chain extender compound, based upon the total weight of the polyurethane formulation.

[0049] The polyurethane formulation may further comprise a catalyst. The catalyst is not particularly limited, and any catalyst known in the art may be used. The catalyst may be present in the polyurethane formulation in an amount of from 0.001 wt% to 2 wt%, or from 0.1 wt% to 1 wt%, or from 0.1 wt% to 0.5 wt%, based upon the total weight of the polyurethane formulation. Representative catalysts include, but are not limited to, bis-(2-dimethylaminoethyl)ether (JEFFCAT® ZF-20 catalyst), N,N,N'-trimethyl-N'- hydroxyethylbisaminoethylether (JEFFCAT® ZF-10 catalyst), N-(3- dimethylaminopropyl)-N,N-diisopropanolamine (JEFFCAT® DPA catalyst), N,N- dimethylethanolamine (JEFFCAT® DMEA catalyst), triethylene diamine (JEFFCAT® TEDA catalyst), blends of N,N-dimethylethanolamine ethylene diamine (such as JEFFCAT® TD-20 catalyst), N,N-dimethylcyclohexylamine (JEFFCAT® DMCHA catalyst), benzyldimethylamine (JEFFCAT® BDMA catalyst),10 EU-51184pentamethyldiethylenetriamine (JEFFCAT® PMDETA catalyst), N,N,N',N",N"-pentamethyldipropylenetriamine (JEFFCAT® ZR-40 catalyst), N,N-bis(3-dimethylaminopropyl)-N-isopropanolamine (JEFFCAT® ZR-50 catalyst), N'-(3-(dimethylamino)propyl -N,N-dimethyl -1,3 -propanediamine (JEFFCAT ® Z- 130 catalyst), 2-(2-dimethylaminoethoxy)ethanol (JEFFCAT® ZR-70 catalyst), N,N,N-trimethylaminoethyl-ethanolamine (JEFFCAT® Z-110 catalyst), N-ethylmorpholine (JEFFCAT® NEM catalyst), N-methylmorpholine (JEFFCAT® NMM catalyst), 4-methoxyethylmorpholine, N,N'dimethylpiperzine (JEFFCAT® DMP catalyst), 2,2'-dimorpholinodiethylether (JEFFCAT® DMDEE catalyst), 1 ,3,5-tris(3- (dimethylamino)propyl)-hexahydro-s-triazine (JEFFCAT® TR-90 catalyst), 1-propanamine, 3-(2-(dimethylamino)ethoxy), substituted imidazoles such as 1,2-dimethlyimidazol and l-methyl-2-hydroxy ethylimidazole, N,N'-dimethylpiperazines or bis-substituted piperazines such aminoethylpiperazine, N,N',N' -trimethyl aminoethylpiperazine or bis-(N-methyl piperazine)urea, N-methylpyrrolidines and substituted methylpyrrolidines such as 2-aminoethyl-N-methylpyrrolidine or bis-(N-methylpyrrolidine)ethyl urea, 3 -dimethylaminopropylamine, N,N,N",N"-tetramethyldipropylenetriamine, tetramethylguanidine, 1,2-bis-diisopropanol. Other examples of amine catalysts include N-alkylmorpholines, such as N-methylmorpholine, N-ethylmorpholine, N-butylmorpholine and dimorpholinodiethylether, N,N'-dimethylaminoethanol, N,N-dimethylamino ethoxy ethanol, bis-(dimethylaminopropyl)-amino-2-propanol, bis-(dimethylamino)-2-propanol, bis-(N,N-dimethylamino)ethyl ether; N,N,N'-trimethyl-N'hydroxyethyl-bis-(aminoethyl)ether, N,N-dimethyl amino ethyl-N'-methyl amino ethanol, tetramethyliminobispropylamine, Poly cat SA1 / 10, Poly cat SA2 LE, Poly cat SA 4, Poly cat SA 5 from Evonik and Toyocat' DB 30, Toyocat DB 40, Toyocat DB 60 from Tosoh, N- methylimidazole, 1,2-dimethylimidazole, N-methylmorpholine, N-ethylmorpholine, triethylamine, N,N'-dimethylpiperazine, 1,3,5- tris(dimethylaminopropyl)hexahydrotriazine, 2,4,6-tris(dimethylaminomethyl)phenol, N- methyl dicyclohexylamine, pentamethyl dipropylene triamine, N-methyl-N'-(2- dimethylamino)-ethyl-piperazine, tributylamine, pentamethyl diethylene triamine, hexamethyltriethylene tetramine, heptamethyltetraethylenepentamine, dimethylaminocyclohexylamine, pentamethyldipropylene-triamine, triethanolamine, dimethylethanolamine, bis(dimethylaminoethyl)ether, tris(3-dimethylamino)propyl amine, JeffcatDPA, Jeffcat Z130, DabcoNE300, DabcoNE1091 andDabcoNE1550. Additionally, metal catalysts11 EU-51184can be used. Suitable metal catalysts include, but are not limited to, organometallic compounds such as those comprising at least one transition metal. The transition metal may be selected from Groups IVB, VB, VIIB, VIIB and VIIIB of the Periodic Table of the Elements. In some embodiments, the metal catalyst comprises an organometallic compound comprising one or more metals selected from the group consisting of metals of Group VIIIB of the Periodic Table of the Elements, such as iron, tin, bismuth, zinc. In some embodiments, the organometallic compound comprises one or more chelating ligands. Non-limiting examples of such chelating ligands include, but are not limited to, acetyl acetone, alkyl or aryl acetoacetate, gluconate, cyclopentadienyl, or combinations thereof. The catalyst or catalyst package may consist of different combinations of catalysts, including but not limited to combinations of multiple amine catalysts, combinations of multiple metal catalyst or combinations of amine and metal catalysts.

[0050] The polyurethane formulation may further comprise a surfactant. The surfactant may be present in an amount of from 0 weight% to 5 weight% of the total weight of the polyurethane formulation, depending on the requirements of the particular formulation. Examples of suitable commercially available surfactants include, but are not limited to Tegostab B8494, Tegostab B8905, Tegostab B8993, Tegostab B8948, Tegostab B8017, Tegostab B8930, Tegostab B8950, Tegostab B8960, Vorasurf DC193, Vorasurf 5382, Niax L1500, Niax L1550, Niax L1542, Niax UAX 7061, Niax UAX 6897, Niax UAX 6639, Niax UAX 7061, Tegostab B8466 and Tegostab B8416.

[0051] According to an embodiment, the isocyanate index of the polyurethane formulation is in the range of from 85 to 115, or from 90 to 110, or from 95 to 105.

[0052] As used herein, the “isocyanate index” or “NCO index” or “index” is the ratio of NCO- equivalents to the sum of equivalents of isocyanate-reactive hydrogen atoms present in a formulation, given as a percentage:[NCO] x 100 (%)[active hydrogen]In other words, the NCO-index expresses the percentage of isocyanate actually used in a formulation with respect to the amount of isocyanate theoretically required for reacting with the amount of isocyanate-reactive hydrogen used in a formulation. The expression “isocyanate-reactive hydrogen” as used herein for the purpose of calculating the isocyanate index refers to the total of active hydrogen atoms in hydroxyl and amine groups present in the reactive compositions; this means that for12 EU-51184the purpose of calculating the isocyanate index at the actual polymerisation process one hydroxyl group is considered to comprise one reactive hydrogen, one primary amine group is considered to comprise one reactive hydrogen and one water molecule is considered to comprise two active hydrogens.

[0053] In one embodiment, the polyurethane formulation may comprise from 35 weight% to 45 weight% of component (i), from 15 weight% to 50 weight% of component (ii), from 5 weight% to 40 weight% of component (iii), and from 5 weight% to 15 weight% of component (iv), based upon the total weight of the formulation. In one embodiment, the polyurethane formulation may comprise from 35 weight% to 45 weight% of component (i), from 20 weight% to 50 weight% of component (ii), from 10 weight% to 35 weight% of component (iii), and from 5 weight% to 15 weight% of component (iv).

[0054] In one embodiment, the polyurethane formulation comprises the following components:i) 4,4'-diisocyanatodicyclohexylmethane (H12MDI) or prepolymer thereof; ii) pTHF polyol compound or alkylene oxide-based polyether polyol compound or combination thereof;iii) a polycaprolactone compound (PCL); andiv) a chain extender compound having a molar mass below 500 g / mol.

[0055] In one embodiment, the polyurethane formulation comprises the following components:i) 4,4'-diisocyanatodicyclohexylmethane (H12MDI);ii) pTHF polyol compound or alkylene oxide-based polyether polyol compound or combination thereof;iii) a polycaprolactone compound (PCL); andiv) a chain extender compound having a molar mass below 500 g / mol, wherein the weight ratio of the component (ii) to component (iii) in the polyurethane formulation is from 10:1 to 1:2.

[0056] In one embodiment, the polyurethane formulation comprises the following components:i) 4,4'-diisocyanatodicyclohexylmethane (H12MDI);ii) pTHF polyol compound or alkylene oxide-based polyether polyol compound or combination thereof;iii) a polycaprolactone compound (PCL) obtainable by reacting caprolactam with ethylene glycol, diethylene glycol or neopentyl diol; andiv) a chain extender compound selected from ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, tripropylene glycol and a combination thereof,13 EU-51184wherein the weight ratio of component (ii) to component (iii) in the polyurethane formulation is from 10:1 to 1:2, or from 5:1 to 1:1.

[0057] In one embodiment, the polyurethane formulation comprises the following components:i) 4,4'-diisocyanatodicyclohexylmethane (H12MDI);ii) pTHF polyol compound;iii) a polycaprolactone compound (PCL) obtainable by reacting caprolactam with ethylene glycol, diethylene glycol or neopentyl diol; andiv) a chain extender compound selected from 1,4-butanediol,wherein the weight ratio of component (ii) to component (iii) in the polyurethane formulation is from 10:1 to 1:2, or from 5:1 to 1:1.

[0058] According to an embodiment, the hardblock content of the polyurethane is from 30 % to 80 %, or from 35 % to 75 %, or from 40 % to 70 %, or from 45 % to 65 %, or from 50 % to 60 %.

[0059] The term “hardblock” used herein refers to 100 times the ratio of the amount (in parts by weight, pbw) of polyisocyanate + isocyanate-reactive compounds having a weightaverage molecular weight of less than about 500 g / mol (wherein isocyanate-reactive compounds having a molecular weight of more than 500 g / mol incorporated in the polyisocyanates are not taken into account) over the amount (in pbw) of all polyisocyanate + all isocyanate-reactive compounds used. The hardblock content is expressed in %.

[0060] In one embodiment, the thermoplastic polyurethane film has a tensile strength of greater than 30 MPa, or greater than 40 MPa, or greater than 45 MPa, or greater than 50 MPa, or from 30 MPa to 100 MPa, when measured according to ASTM D412- 16(2021).

[0061] In one embodiment, the thermoplastic polyurethane film has a tear strength of greater than 2.7 MPa, or greater than 3.0 MPa, or greater than 3.3 MPa, or greater than 3.4 MPa, or from 2.7 MPa to 20 MPa, when measured according to ASTM D624-00(2020).

[0062] [Thermoplastic polyurethane film formed from a blend of a first thermoplastic polyurethane and a second thermoplastic polyurethane (physical blend)]

[0063] In another aspect, the thermoplastic polyurethane film is formed from a blend of a first thermoplastic polyurethane and a second thermoplastic polyurethane. The form of the thermoplastic polyurethane is not particularly limited and may be pellets, granules, flakes or beads.14 EU-51184

[0064] The first thermoplastic polyurethane is obtained from a first polyurethane formulation.In particular, the first thermoplastic polyurethane is obtained from reacting the components of the first polyurethane formulation.

[0065] The first polyurethane formulation comprises: i) 4,4'-diisocyanatodicyclohexylmethane (H12MDI) or prepolymer thereof; ii) a polyether polyol compound; and iii) a chain extender compound. Further components may be present, as is the case for the polyurethane formulation described above.

[0066] The definitions of the H12MDI or prepolymer thereof, the polyether polyol compound and the chain extender compound in the first polyurethane formulation are the same as described above with respect to the polyurethane formulation (chemical blend).

[0067] In one embodiment, the first polyurethane formulation does not contain any further polyisocyanate compounds besides H12MDI.

[0068] In one embodiment, the first polyurethane formulation may comprise from 30 weight% to 50 weight% of component (i), from 35 weight% to 60 weight% of component (ii), and from 2 weight% to 20 weight% of component (iii), based upon the total weight of the formulation. In one embodiment, the first polyurethane formulation may comprise from 35 weight% to 45 weight% of component (i), from 40 weight% to 55 weight% of component (ii), and from 5 weight% to 15 weight% of component (iii), based upon the total weight of the formulation.

[0069] The second thermoplastic polyurethane is obtained from a second polyurethane formulation. In particular, the second thermoplastic polyurethane is obtained from reacting the components of the second polyurethane formulation.

[0070] The second polyurethane formulation comprises: i) 4,4'- diisocyanatodicyclohexylmethane (H12MDI) or prepolymer thereof; ii) a polycaprolactone compound; and iii) a chain extender compound. Further components may be present, as is the case for the polyurethane formulation described above.

[0071] The definitions of the H12MDI or prepolymer thereof, the poly caprolactone compound and the chain extender compound in the second polyurethane formulation are the same as described above with respect to the polyurethane formulation (chemical blend).

[0072] In one embodiment, the second polyurethane formulation does not contain any further polyisocyanate compounds besides H12MDI.

[0073] In one embodiment, the second polyurethane formulation may comprise from 30 weight% to 50 weight% of component (i), from 35 weight% to 60 weight% of component (ii), and from 2 weight% to 20 weight% of component (iii), based upon the total weight of15 EU-51184the formulation. In one embodiment, the second polyurethane formulation may comprise from 35 weight% to 45 weight% of component (i), from 40 weight% to 55 weight% of component (ii), and from 5 weight% to 15 weight% of component (iii), based upon the total weight of the formulation.

[0074] In one embodiment, the weight ratio of the first thermoplastic polyurethane to the second thermoplastic polyurethane in the blend is from 20: 1 to 1 : 10, or from 10: 1 to 1 :4, or from 10:1 to 1:2, or from 5:1 to 1:2, or from 5:1 to 1:1, or from 4:1 to 1:1, or from 4: 1 to 2: 1. In one embodiment, the weight ratio of the first thermoplastic polyurethane to the second thermoplastic polyurethane in the blend is from 10:1 to 5:1, or from 10:1 to 8:1.

[0075] In one embodiment, the first polyurethane formulation comprises the following components:i) 4,4'-diisocyanatodicyclohexylmethane (H12MDI);ii) pTHF polyol compound or alkylene oxide-based polyether polyol compound or combination thereof; andiii) a chain extender compound selected from ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, tripropylene glycol and a combination thereof,and the second polyurethane formulation comprises the following components:i) 4,4'-diisocyanatodicyclohexylmethane (H12MDI);ii) a polycaprolactone compound (PCL) obtainable by reacting caprolactam with ethylene glycol, diethylene glycol or neopentyl diol; andiii) a chain extender compound selected from ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, tripropylene glycol and a combination thereof.

[0076] In one embodiment, the first polyurethane formulation comprises the following components:i) 4,4'-diisocyanatodicyclohexylmethane (H12MDI);ii) pTHF polyol compound; andiii) a chain extender compound selected from 1,4-butanediol,and the second polyurethane formulation comprises the following components:i) 4,4'-diisocyanatodicyclohexylmethane (H12MDI);ii) a polycaprolactone compound (PCL) obtainable by reacting caprolactam with ethylene glycol, diethylene glycol or neopentyl diol; and16 EU-51184iii) a chain extender compound selected from 1,4-butanediol.

[0077] In one embodiment, the blend of the first thermoplastic polyurethane to the second thermoplastic polyurethane has a hard block content of 35% to 75%, or 40% to 70%, or 45% to 65%, or 45% to 60%, or 45% to 55%.

[0078] In one embodiment, the thermoplastic polyurethane film has a tensile strength of greater than 30 MPa, or greater than 40 MPa, or greater than 45 MPa, or greater than 50 MPa, or greater than 55 MPa, or from 30 MPa to 100 MPa, when measured according to ASTM D412- 16(2021).

[0079] In one embodiment, the thermoplastic polyurethane film has a tear strength of greater than 2.7 MPa, or greater than 3.0 MPa, or greater than 3.3 MPa, or greater than 3.4 MPa, or from 2.7 MPa to 20 MPa, when measured according to ASTM D624-00(2020).

[0080] [Method of preparing a paint protection film]

[0081] The method of preparing a paint protection film comprises the following steps: step a) providing a thermoplastic polyurethane as defined herein or a blend of a first thermoplastic polyurethane and a second thermoplastic polyurethane as defined herein; and step b) forming a thermoplastic polyurethane film from the thermoplastic polyurethane.

[0082] In one embodiment, step b) comprises extruding the thermoplastic polyurethane into a film.

[0083] In one embodiment, the temperature for the extruding step is from 100°C to 250°C or from 120°C to 220°C. The skilled person would change the extrusion as necessary depending on the polyurethane to be processed.

[0084] In one embodiment, the method further comprises physically blending the first thermoplastic polyurethane and the second thermoplastic polyurethane by extrusion blending.

[0085] In one embodiment, the extrusion blending is single-screw or twin-screw extrusion blending.

[0086] In one embodiment, the method further comprises a step of providing a top layer and an adhesion layer.

[0087] [Examples]

[0088] The present disclosure will be described in more detail with reference to the Examples. The present disclosure is not limited to the following Examples.

[0089] Materials used:17 EU-51184

[0090] H12MDI with an average NCO value of 33.60%; polycaprolactone (PCL) with a weight average molecular weight of 1250 g / mol and an average hydroxyl value of 91.5 mg KOH / g; polytetrahydrofuran (pTHF) with a weight average molecular weight of 1000 g / mol and an average hydroxyl value of 113 mg KOH / g; 1,4-butanediol (BDO).

[0091] Example 1 (chemical blending):

[0092] A thermoplastic polyurethane was synthesised through a one-shot process by mixing H12MDI, PCL, pTHF, BDO and additives (commercially available catalyst, antioxidant and UV stabilizer) in a reaction vessel at 350 rpm stirring rate. After the reaction mixture reached 90°C, it was poured into a Teflon lined mould and set in an oven at 140°C for two hours post curing to form a thermoplastic polyurethane block. The thermoplastic polyurethane had a hardblock content of 52%, and the weight ratio of pTHF to PCL used to form the thermoplastic polyurethane was 3:1.

[0093] The thermoplastic polyurethane block was then granulated and the resultant granules were then fed into an extruder to be pelletized. The resultant pellets were then extruded into films for property evaluation. Table 1 shows the properties of the films formed in Example 1.

[0094] Comparative Example 1:

[0095] A thermoplastic polyurethane was synthesised through a one-shot process by mixing H12MDI, PCL, BDO and additives (commercially available catalyst, antioxidant and UV stabilizer) in a reaction vessel at 350 rpm stirring rate. After the reaction mixture reached 90°C, it was poured into a Teflon lined mould and set in an oven at 140°C for two hours post curing to form a thermoplastic polyurethane block. The thermoplastic polyurethane had a hardblock content of 50%.

[0096] The thermoplastic polyurethane block was then granulated and the resultant granules were then fed into an extruder to be pelletized. The resultant pellets were then extruded into films for property evaluation. Table 1 shows the properties of the films formed in Comparative Example 1.

[0097] Comparative Example 2:

[0098] A thermoplastic polyurethane was synthesised through a one-shot process by mixing H12MDI, pTHF, BDO and additives (commercially available catalyst, antioxidant and UV stabilizer) in a reaction vessel at 350 rpm stirring rate. After the reaction mixture reached 90°C, it was poured into a Teflon lined mould and set in an oven at 140°C for two hours post curing to form a thermoplastic polyurethane block. The thermoplastic polyurethane had a hardblock content of 52%.18 EU-51184

[0099] The thermoplastic polyurethane block was then granulated and the resultant granules were then fed into an extruder to be pelletized. The resultant pellets were then extruded into films for property evaluation. Table 1 shows the properties of the films formed in Comparative Example 2.

[0100] Example 2 (physical blending):

[0101] The thermoplastic polyurethane granules formed in Comparative Examples 1 and 2 were physically blended via a single screw extruder in a 1:1 weight ratio (1 part by weight of the thermoplastic polyurethane granules formed in Comparative Example 1 and 1 part by weight of the thermoplastic polyurethane granules formed in Comparative Example 2) to form pellets.

[0102] The resultant pellets were then extruded into films for property evaluation. Table 1 shows the properties of the films formed in Example 2.

[0103] Example 3 (physical blending):

[0104] The thermoplastic polyurethane granules formed in Comparative Examples 1 and 2 were physically blended via a twin-screw extruder in a 1 : 1 weight ratio (1 part by weight of the thermoplastic polyurethane granules formed in Comparative Example 1 and 1 part by weight of the thermoplastic polyurethane granules formed in Comparative Example 2) to form pellets.

[0105] The resultant pellets were then extruded into films for property evaluation. Table 1 shows the properties of the films formed in Example 3.

[0106] Example 4 (physical blending):

[0107] The thermoplastic polyurethane granules formed in Comparative Examples 1 and 2 were physically blended via a single screw extruder in a 1:9 weight ratio (1 parts by weight of the thermoplastic polyurethane granules formed in Comparative Example 1 and 9 parts by weight of the thermoplastic polyurethane granules formed in Comparative Example 2) to form pellets.

[0108] The resultant pellets were then extruded into films for property evaluation. Table 1 shows the properties of the films formed in Example 4.

[0109] Example 5 (physical blending):

[0110] The thermoplastic polyurethane granules formed in Comparative Examples 1 and 2 were physically blended via a single screw extruder in a 3:7 weight ratio (3 parts by weight of the thermoplastic polyurethane granules formed in Comparative Example 1 and 7 parts by weight of the thermoplastic polyurethane granules formed in Comparative Example 2) to form pellets.19 EU-51184

[0111] The resultant pellets were then extruded into films for property evaluation. Table 1 shows the properties of the films formed in Example 5.

[0112] Table 1:

[0113] The tensile properties (tensile strength, elongation, tensile modulus) of the films in the examples were determined on an Instron machine according to ASTM D412- 16(2021) (method A; dog bone specimen). The tear strength of the films in the examples was determined on an Instron machine according to ASTM D624-00(2020). The initial colour (yellowness index) of the films in the examples was measured according to ASTM E313-20 with a B YK colorimeter. Haze and luminous transmittance of the films in the examples were measured according to ASTM D1003-21 using a Haze-guard Plus machine from BYK. Solvent resistance of the films in the examples was evaluated by fully submerging the films into the solvent being tested (gasoline or lubricant oil) for 30 minutes, the films were then observed, and shrinkage was measured.20 EU-51184

[0114] From the results in Table 1, it can be seen that films according to the present disclosure (Examples 1-5) have excellent mechanical properties as well as excellent solvent resistance and colour. These properties make the films according to the present disclosure particularly suited for paint protection on automobiles, in a cost-effective manner. Comparative Example 1 represents a premium PPF and Comparative Example 2 replaces the PCL of Comparative Example 1 with pTHF. It is clear that the films of Examples 1-5 have comparable properties, and in some cases improved properties, relative to the film of Comparative Example 1, and have many improved properties with respect to the film of Comparative Example 2. In particular, the films according to the present disclosure surprisingly have improved shrinkage when exposed to gasoline (see Examples 1-5 vs Comparative Examples 1 and 2).

[0115] Moreover, the films of Examples 1-5 have improved tear strength relative to a simple linear calculation of tear strength based on the relative proportions of the granules of Comparative Examples 1 and 2 used to form the films of Examples 1-5.

[0116] All ranges described herein are exemplary in nature and include any and all values in between. The terms “substantially”, “approximately” and “about” used herein are interchangeable and refer to a measurement that includes the stated measurement and any measurements reasonably close to the stated measurement. Measurements that are reasonably close to the stated measurement deviate from the stated measurement by a reasonably small amount as understood and readily ascertained by individuals having ordinary skill in the relevant art. Such deviations may be attributable to measurement error, differences in measurement and / or manufacturing equipment calibrations, human error in reading and / or setting measurements, minor adjustments made to optimize performance and / or structural parameters in view of differences in measurement associated with other components, particular implementation scenarios, imprecise adjustment and / or manipulation of objects by a person or machine. In the event it is determined that individuals having ordinary skill in the relevant art would not readily ascertain values for such reasonably small differences, the terms “about” and “approximately” can be understood to mean plus or minus 10% of the stated value.

[0117] Throughout the description and claims, the terms take the meanings explicitly defined herein, unless the context clearly dictates otherwise.

[0118] The phrases “in one embodiment”, “in an embodiment” and “in some embodiments” etc. as used herein do not necessarily refer to the same embodiment(s), though they may. Furthermore, the phrases “in another embodiment” and “in some other embodiments”21 EU-51184as used herein do not necessarily refer to a different embodiment, though they may. All embodiments of the present disclosure are intended to be combinable.

[0119] The terms “comprises” and “comprising” mean to include but not limited to, such that further features may be present. The terms may also mean to consist of or consist essentially of.

[0120] All references and test methods cited herein are incorporated by reference in their entireties.

Claims

1 EU-51184CLAIMS1. A paint protection film comprising a thermoplastic polyurethane film, wherein the thermoplastic polyurethane film is formed from a thermoplastic polyurethane, wherein the thermoplastic polyurethane is obtained from a polyurethane formulation comprising the following components:i) 4,4'-diisocyanatodicyclohexylmethane (H12MDI) or prepolymer thereof; ii) a polyether polyol compound;iii) a polycaprolactone compound (PCL); andiv) a chain extender compound.

2. A paint protection film according to Claim 1, wherein the poly ether polyol compound is any one selected from a polytetrahydrofuran polyol (pTHF or PTMEG), an alkylene oxide-based polyether polyol, and a combination thereof.

3. A paint protection film according to Claim 1 or Claim 2, wherein the chain extender compound is a compound having a molar mass below 500 g / mol, and is preferably any one selected from ethylene glycol, di ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, methylpentanediol, 1,6-hexanediol, dipropylene glycol, tripropylene glycol and a combination thereof.

4. A paint protection film according to any preceding claim, wherein the weight ratio of the polyether polyol compound (component (ii)) to the polycaprolactone compound (component (iii)) in the polyurethane formulation is from 20: 1 to 1 :4.

5. A paint protection film according to any preceding claim, wherein component (i) is present in the polyurethane formulation in an amount of from 35 to 45 weight%, based upon the total weight of the polyurethane formulation.

6. A paint protection film according to any preceding claim, wherein component (ii) is present in the polyurethane formulation in an amount of from 10 to 55 weight%, based upon the total weight of the polyurethane formulation.23 EU-511847. A paint protection film according to any preceding claim, wherein component (iii) is present in the polyurethane formulation in an amount of from 5 to 40 weight%, based upon the total weight of the polyurethane formulation.

8. A paint protection film according to any preceding claim, wherein component (iv) is present in the polyurethane formulation in an amount of from 5 to 15 weight%, based upon the total weight of the polyurethane formulation.

9. A paint protection film according to any preceding claim, wherein the thermoplastic polyurethane has a hardblock content of 35% to 75 %, preferably 45% to 65%.

10. A paint protection film comprising a thermoplastic polyurethane film, wherein the thermoplastic polyurethane film is formed from a blend of a first thermoplastic polyurethane and a second thermoplastic polyurethane, wherein the first thermoplastic polyurethane is obtained from a first polyurethane formulation comprising:i) 4,4'-diisocyanatodicyclohexylmethane (H12MDI) or prepolymer thereof; ii) a polyether polyol compound; andiii) a chain extender compound,and the second thermoplastic polyurethane is obtained from a second polyurethane formulation comprising:i) 4,4'-diisocyanatodicyclohexylmethane (H12MDI) or prepolymer thereof; ii) a polycaprolactone compound; andiii) a chain extender compound.

11. A paint protection film according to Claim 10, wherein the poly ether polyol compound is any one selected from a polytetrahydrofuran polyol (pTHF or PTMEG), an alkylene oxide-based polyether polyol, and a combination thereof.

12. A paint protection film according to Claim 10 or Claim 11, wherein the chain extender compound is a compound having a molar mass below 500 g / mol, and is preferably any one selected from ethylene glycol, di ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, methylpentanediol, 1,6-hexanediol, dipropylene glycol, tripropylene glycol and a combination thereof.24 EU-5118413. A paint protection film according to any of Claims 10-12, wherein the weight ratio of the first thermoplastic polyurethane to the second thermoplastic polyurethane in the blend is from 20: 1 to 1 :4.

14. A paint protection film according to any of Claims 10-13, wherein the blend of the first thermoplastic polyurethane and the second thermoplastic polyurethane has a hardblock content of 35% to 75%, preferably 45% to 60%.

15. A method of preparing a paint protection film comprising the following steps:step a) providing a thermoplastic polyurethane as defined in any of Claims 1-9 or a blend of a first thermoplastic polyurethane and a second thermoplastic polyurethane as defined in any of Claims 10-14; andstep b) forming a thermoplastic polyurethane film from the thermoplastic polyurethane or the blend of the first thermoplastic polyurethane and the second thermoplastic polyurethane.

16. A method according to Claim 15, wherein step b) comprises extruding the thermoplastic polyurethane or the blend of the first thermoplastic polyurethane and the second thermoplastic polyurethane into a film.

17. A method according to Claim 15 or Claim 16, further comprising physically blending the first thermoplastic polyurethane and the second thermoplastic polyurethane by extrusion blending, optionally wherein the extrusion blending is single-screw or twin- screw extrusion blending.

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