Thermoplastic polyurethane resins, films and paint protection films

Abstract

A thermoplastic polyurethane resin according to the present invention contains a reaction product of a polyisocyanate component and a polyol component. The polyisocyanate component contains 1,4-bis(isocyanatomethyl)cyclohexane and 1,3-bis(isocyanatomethyl)cyclohexane. The polyol component contains a polycarbonate polyol and a low-molecular-weight polyol. The polycarbonate polyol contains a crystalline polycarbonate polyol that is in a solid state at 25°C. Relative to the total amount of 1,4-bis(isocyanatomethyl)cyclohexane and 1,3-bis(isocyanatomethyl)cyclohexane, the amount of 1,4-bis(isocyanatomethyl)cyclohexane is 50-90% by mole and the amount of 1,3-bis(isocyanatomethyl)cyclohexane is 10-50% by mole.

Description

[Technical Field]

[0001] The present invention relates to a thermoplastic polyurethane resin, a film, and a paint protection film. [Background technology]

[0002] Thermoplastic polyurethane resins (TPUs) are generally obtained by the reaction of polyisocyanate, macropolyol, and low-molecular-weight polyol. Thermoplastic polyurethane resins are molded into, for example, a film. Film-like thermoplastic polyurethane resins are used as base films in paint protection films (PPFs, laminated films) for protecting the painted surfaces of automobiles.

[0003] For example, the following films are known as base films for paint protection films (PPF). The film contains a thermoplastic polyurethane resin. The thermoplastic polyurethane resin contains a reaction product of a polyisocyanate component and a polyol component. The polyisocyanate component contains 1,4-bis(isocyanatomethyl)cyclohexane. The polyol component contains an amorphous polycarbonate diol that is liquid at 25°C and a low-molecular-weight diol having 2 to 6 carbon atoms (see, for example, Patent Document 1).

[0004] Such a film has excellent elastic properties (recovery force) and heat resistance. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 069802 Summary of the Invention [Problem to be solved by the invention]

[0006] On the other hand, the film is also required to have the ability to recover from fingerprints (fingerprint recovery), and in this regard, the above-mentioned films may not have sufficient fingerprint recovery.

[0007] The present invention relates to a thermoplastic polyurethane resin that combines stretchability (recovery force), heat resistance, and finger mark recovery, and to a film and paint protection film that contain the thermoplastic polyurethane resin. [Means for solving the problem]

[0008] The present invention [1] is a thermoplastic polyurethane resin containing a reaction product of a polyisocyanate component and a polyol component, wherein the polyisocyanate component contains 1,4-bis(isocyanatomethyl)cyclohexane and 1,3-bis(isocyanatomethyl)cyclohexane, the polyol component contains a polycarbonate polyol and a low-molecular-weight polyol, the polycarbonate polyol contains a crystalline polycarbonate polyol that is solid at 25°C, and the proportion of 1,4-bis(isocyanatomethyl)cyclohexane relative to the total amount of 1,4-bis(isocyanatomethyl)cyclohexane and 1,3-bis(isocyanatomethyl)cyclohexane is 50 mol% or more and 90 mol% or less, and the proportion of 1,3-bis(isocyanatomethyl)cyclohexane is 10 mol% or more and 50 mol% or less.

[0009] The present invention [2] includes the thermoplastic polyurethane resin according to the above [1], in which the polycarbonate polyol is the crystalline polycarbonate polyol.

[0010] The present invention [3] includes the thermoplastic polyurethane resin according to the above [1] or [2], wherein the hard segment concentration of the thermoplastic polyurethane resin is 18% by mass or more and 35% by mass or less.

[0011] The present invention [4] comprises the thermoplastic polyurethane resin according to any one of the above [1] to [3], wherein the polycarbonate polyol comprises a first polycarbonate polyol having a number average molecular weight of 1,200 or less and a second polycarbonate polyol having a number average molecular weight of 1,800 or more.

[0012] The present invention [5] includes a film containing the thermoplastic polyurethane resin according to any one of the above [1] to [4].

[0013] The present invention [6] includes a paint protection film comprising a release layer, an adhesive layer disposed on at least one side of the release layer, and a base film layer disposed on at least one side of the adhesive layer, wherein the base film layer contains the film described in [5] above. [Effects of the Invention]

[0014] The raw material components of the thermoplastic polyurethane resin of the present invention contain a predetermined ratio of 1,4-bis(isocyanatomethyl)cyclohexane, a crystalline polycarbonate polyol, and a polyol component containing a low-molecular-weight polyol.

[0015] 1,4-bis(isocyanatomethyl)cyclohexane has relatively high crystallinity. Low-molecular-weight polyols form hard segments and improve crystallinity. Crystalline polycarbonate polyols have relatively high crystallinity.

[0016] The raw material components also contain 1,3-bis(isocyanatomethyl)cyclohexane, which has relatively low crystallinity.

[0017] In the raw material components, the ratio of 1,4-bis(isocyanatomethyl)cyclohexane to 1,3-bis(isocyanatomethyl)cyclohexane is adjusted to fall within a predetermined range.

[0018] In other words, the crystallinity of the polyurethane structure is adjusted by the raw material components, which gives the thermoplastic polyurethane resin a good balance of elasticity (rebound force), heat resistance, and finger print recovery.

[0019] Furthermore, since the film and paint protection film of the present invention contain the above-mentioned thermoplastic polyurethane resin, they have a good balance of finger mark recovery, stretchability (recovery force), and heat resistance. DETAILED DESCRIPTION OF THE INVENTION

[0020] The thermoplastic polyurethane resin of the present invention is obtained by reacting a polyisocyanate component with a polyol component. In other words, the thermoplastic polyurethane resin is a reaction product of a polyisocyanate component and a polyol component.

[0021] 1. Polyisocyanate component (1) Bis(isocyanatomethyl)cyclohexane The polyisocyanate component contains bis(isocyanatomethyl)cyclohexane (H6XDI) as an essential component. Bis(isocyanatomethyl)cyclohexane includes 1,4-bis(isocyanatomethyl)cyclohexane and 1,3-bis(isocyanatomethyl)cyclohexane.

[0022] 1,4-bis(isocyanatomethyl)cyclohexane (1,4-H6XDI) has stereoisomers, including cis-1,4-bis(isocyanatomethyl)cyclohexane (hereinafter referred to as cis 1,4 isomer) and trans-1,4-bis(isocyanatomethyl)cyclohexane (hereinafter referred to as trans 1,4 isomer).

[0023] 1,4-bis(isocyanatomethyl)cyclohexane contains, for example, a trans-1,4 isomer (trans isomer) and a cis-1,4 isomer (cis isomer), with the total amount of the trans-1,4 isomer and the cis-1,4 isomer being 100 mol %.

[0024] The content of the trans-1,4 isomer (trans isomer) relative to the total moles of 1,4-bis(isocyanatomethyl)cyclohexane is, for example, 60 mol% or more, preferably 70 mol% or more, more preferably 75 mol% or more, and even more preferably 80 mol% or more. The content of the trans-1,4 isomer (trans isomer) relative to the total moles of 1,4-bis(isocyanatomethyl)cyclohexane is, for example, 99.5 mol% or less, preferably 99 mol% or less, more preferably 96 mol% or less, and even more preferably 90 mol% or less.

[0025] In other words, the content of cis-1,4 isomer (cis isomer) relative to the total moles of 1,4-bis(isocyanatomethyl)cyclohexane is, for example, 0.5 mol% or more, preferably 1 mol% or more, more preferably 4 mol% or more, and even more preferably 10 mol% or more. Also, the content of cis-1,4 isomer (cis isomer) relative to the total moles of 1,4-bis(isocyanatomethyl)cyclohexane is, for example, 40 mol% or less, preferably 30 mol% or less, more preferably 25 mol% or less, and even more preferably 20 mol% or less.

[0026] 1,4-bis(isocyanatomethyl)cyclohexane is produced by a known method. Methods for producing 1,4-bis(isocyanatomethyl)cyclohexane are described in, for example, WO 2009 / 051114 and WO 2019 / 069802.

[0027] 1,4-bis(isocyanatomethyl)cyclohexane may be a monomer or a modified product. Examples of modified products include uretdione modified products, isocyanurate modified products, iminooxadiazinedione, biuret modified products, allophanate modified products, polyol adducts, oxadiazinetrione modified products, and carbodiimide modified products. These may be used alone or in combination of two or more types. 1,4-bis(isocyanatomethyl)cyclohexane is preferably a monomer.

[0028] The 1,3-bis(isocyanatomethyl)cyclohexane (1,3-H6XDI) is not particularly limited, and known 1,3-bis(isocyanatomethyl)cyclohexane may be used.

[0029] 1,3-bis(isocyanatomethyl)cyclohexane may be a monomer or a modified product. Examples of modified products include uretdione modified products, isocyanurate modified products, iminooxadiazinedione, biuret modified products, allophanate modified products, polyol adducts, oxadiazinetrione modified products, and carbodiimide modified products. These may be used alone or in combination of two or more types. 1,3-bis(isocyanatomethyl)cyclohexane is preferably a monomer.

[0030] In order to achieve a balanced improvement in the stretch properties (rebound force), heat resistance, and finger print recovery of thermoplastic polyurethane resin, 1,4-bis(isocyanatomethyl)cyclohexane and 1,3-bis(isocyanatomethyl)cyclohexane are used in combination in a specified ratio.

[0031] More specifically, the proportion of 1,4-bis(isocyanatomethyl)cyclohexane relative to the total amount of 1,4-bis(isocyanatomethyl)cyclohexane and 1,3-bis(isocyanatomethyl)cyclohexane is 50 mol% or more, preferably 55 mol% or more, more preferably 60 mol% or more, and even more preferably 65 mol% or more. Also, the proportion of 1,4-bis(isocyanatomethyl)cyclohexane relative to the total amount of 1,4-bis(isocyanatomethyl)cyclohexane and 1,3-bis(isocyanatomethyl)cyclohexane is 90 mol% or less, preferably 85 mol% or less, more preferably 80 mol% or less, and even more preferably 75 mol% or less.

[0032] The proportion of 1,3-bis(isocyanatomethyl)cyclohexane relative to the total amount of 1,4-bis(isocyanatomethyl)cyclohexane and 1,3-bis(isocyanatomethyl)cyclohexane is 10 mol% or more, preferably 15 mol% or more, more preferably 20 mol% or more, and even more preferably 25 mol% or more. The proportion of 1,3-bis(isocyanatomethyl)cyclohexane relative to the total amount of 1,4-bis(isocyanatomethyl)cyclohexane and 1,3-bis(isocyanatomethyl)cyclohexane is 50 mol% or less, preferably 45 mol% or less, more preferably 40 mol% or less, and even more preferably 35 mol% or less.

[0033] (2) Other polyisocyanates The polyisocyanate component may optionally contain other polyisocyanates, which are polyisocyanates other than bis(isocyanatomethyl)cyclohexane.

[0034] Examples of other polyisocyanates include aliphatic polyisocyanates, alicyclic polyisocyanates (excluding bis(isocyanatomethyl)cyclohexane), aromatic polyisocyanates, and araliphatic polyisocyanates.

[0035] Examples of aliphatic polyisocyanates include pentamethylene diisocyanate (PDI) and hexamethylene diisocyanate (HDI). Examples of alicyclic polyisocyanates include isophorone diisocyanate (IPDI), norbornene diisocyanate (NBDI), and methylenebis(cyclohexyl isocyanate) (HDI). 12Examples of aromatic polyisocyanates include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), toluidine diisocyanate (TODI), and naphthalene diisocyanate (NDI). Examples of aralkyl polyisocyanates include xylylene diisocyanate (XDI) and tetramethylxylylene diisocyanate (TMXDI). The other polyisocyanates may be monomers or modified products as described above. These may be used alone or in combination of two or more.

[0036] The content of the other polyisocyanates relative to the total amount of the polyisocyanate components is, for example, 50 mass % or less, preferably 30 mass % or less, more preferably 10 mass % or less, and particularly preferably 0 mass %.

[0037] That is, the content of bis(isocyanatomethyl)cyclohexane is, for example, 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass, relative to the total amount of the polyisocyanate component. In other words, the polyisocyanate component preferably comprises bis(isocyanatomethyl)cyclohexane, and more preferably comprises 1,3-bis(isocyanatomethyl)cyclohexane and 1,4-bis(isocyanatomethyl)cyclohexane.

[0038] 2. Polyol component The polyol component includes a macropolyol and a low molecular weight polyol, and preferably consists of a macropolyol and a low molecular weight polyol.

[0039] (1) Macropolyol Macropolyols are organic compounds with two or more hydroxyl groups in the molecule and a relatively high molecular weight. A relatively high molecular weight means that the number average molecular weight exceeds 400.

[0040] The macropolyol contains a polycarbonate polyol as an essential component, and the polycarbonate polyol contains a crystalline polycarbonate polyol as an essential component.

[0041] Crystalline polycarbonate polyol is a polycarbonate polyol that is solid at 25°C. A solid state refers to a state in which the viscosity at 25°C measured with an E-type viscometer exceeds 500,000 mPa·s.

[0042] Examples of crystalline polycarbonate polyols include ring-opening polymerization products of ethylene carbonate using a polyhydric alcohol as an initiator. Examples of polyhydric alcohols that can be used as initiators include dihydric alcohols having 2 to 8 carbon atoms and trihydric alcohols having 2 to 8 carbon atoms. Examples of dihydric alcohols having 2 to 8 carbon atoms include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, diethylene glycol, and triethylene glycol. Examples of trihydric alcohols having 2 to 8 carbon atoms include glycerin, trimethylolethane, and trimethylolpropane. These can be used alone or in combination of two or more. Preferably, the polyhydric alcohol is a dihydric alcohol.

[0043] The method for ring-opening polymerization of ethylene carbonate with a polyhydric alcohol is not particularly limited, and any known method can be used.

[0044] The number average molecular weight (polystyrene equivalent molecular weight) of the crystalline polycarbonate polyol exceeds 400, preferably is 500 or more, more preferably is 1000 or more. The number average molecular weight (polystyrene equivalent molecular weight) of the crystalline polycarbonate polyol is, for example, 10000 or less, preferably 8000 or less, more preferably 5000 or less, even more preferably 3000 or less, and particularly preferably 2000 or less.

[0045] The average number of hydroxyl groups in the crystalline polycarbonate polyol is, for example, 1.8 or more, preferably 2 or more. The average number of hydroxyl groups in the crystalline polycarbonate polyol is, for example, 4 or less, preferably 3 or less, more preferably 2 or less. The average number of hydroxyl groups in the crystalline polycarbonate polyol is particularly preferably 2. In other words, particularly preferred examples of the crystalline polycarbonate polyol include crystalline polycarbonate diols.

[0046] The polycarbonate polyol may contain an amorphous polycarbonate polyol as an optional component.

[0047] Amorphous polycarbonate polyol is a polycarbonate polyol that is liquid at 25°C. The term "liquid" refers to a state in which the viscosity at 25°C measured with an E-type viscometer is 500,000 mPa·s or less.

[0048] Amorphous polycarbonate polyols can be obtained, for example, by modifying the above-mentioned crystalline polycarbonate polyol with a polyhydric alcohol as a modifying agent. Examples of polyhydric alcohols as modifying agents include dihydric alcohols having 4 to 10 carbon atoms. Examples of dihydric alcohols having 4 to 10 carbon atoms include 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, and 2,2-dimethyl-1,3-propanediol. These can be used alone or in combination of two or more.

[0049] The method for modifying the ring-opening polymer of ethylene carbonate with a dihydric alcohol is not particularly limited, and any known method can be used. For example, ethylene carbonate is ring-opening polymerized by a known method using a dihydric alcohol as an initiator, and then the resulting ring-opening polymer is copolymerized with the dihydric alcohol as a modifying agent.

[0050] The number average molecular weight (polystyrene equivalent molecular weight) of the amorphous polycarbonate polyol exceeds 400, preferably is 500 or more, and more preferably is 1000 or more. The number average molecular weight (polystyrene equivalent molecular weight) of the amorphous polycarbonate polyol is, for example, 10000 or less, preferably 8000 or less, more preferably 5000 or less, even more preferably 3000 or less, and particularly preferably 2000 or less.

[0051] The average number of hydroxyl groups in the amorphous polycarbonate polyol is, for example, 1.8 or more, preferably 2 or more. The average number of hydroxyl groups in the amorphous polycarbonate polyol is, for example, 4 or less, preferably 3 or less, more preferably 2 or less. The average number of hydroxyl groups in the amorphous polycarbonate polyol is particularly preferably 2. In other words, particularly preferred examples of the amorphous polycarbonate polyol include amorphous polycarbonate diols.

[0052] The content of the amorphous polycarbonate polyol relative to the total amount of polycarbonate polyols (total amount of crystalline polycarbonate polyol and amorphous polycarbonate polyol) is, for example, 50 mol% or less, preferably 40 mol% or less, more preferably 30 mol% or less, even more preferably 20 mol% or less, still more preferably 10 mol% or less, and particularly preferably 0 mol%.

[0053] In other words, the content of the crystalline polycarbonate polyol relative to the total amount of polycarbonate polyol (total amount of crystalline polycarbonate polyol and amorphous polycarbonate polyol) is, for example, 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, still more preferably 90 mol% or more, and particularly preferably 100 mol%. That is, the polycarbonate polyol preferably consists of a crystalline polycarbonate polyol.

[0054] The number average molecular weight (polystyrene equivalent molecular weight) of the polycarbonate polyol exceeds 400, preferably is 500 or more, and more preferably is 1000 or more. The number average molecular weight (polystyrene equivalent molecular weight) of the polycarbonate polyol is, for example, 10000 or less, preferably 8000 or less, more preferably 5000 or less, even more preferably 3000 or less, and particularly preferably 2000 or less.

[0055] The average number of hydroxyl groups in the polycarbonate polyol is, for example, 1.8 or more, preferably 2 or more. The average number of hydroxyl groups in the polycarbonate polyol is, for example, 4 or less, preferably 3 or less, more preferably 2 or less. The average number of hydroxyl groups in the polycarbonate polyol is particularly preferably 2. In other words, particularly preferred examples of the polycarbonate polyol include polycarbonate diols.

[0056] The polycarbonate polyols can be used alone or in combination of two or more. Preferably, two or more polycarbonate polyols are used in combination. That is, from the viewpoint of improving the stretching properties (recovery force), heat resistance, and finger mark recovery properties of the thermoplastic polyurethane resin in a well-balanced manner, preferably, two or more polycarbonate polyols are used in combination.

[0057] More specifically, the polycarbonate polyol contains a first polycarbonate polyol having a number average molecular weight of 1,200 or less and a second polycarbonate polyol having a number average molecular weight of 1,800 or more.

[0058] Examples of the first polycarbonate polyol include the above-mentioned crystalline polycarbonate polyol and the above-mentioned amorphous polycarbonate polyol. From the viewpoint of improving the stretchability (recovery force), heat resistance, and finger print recovery of the thermoplastic polyurethane resin in a well-balanced manner, the first polycarbonate polyol is preferably the above-mentioned crystalline polycarbonate polyol.

[0059] The number average molecular weight of the first polycarbonate polyol exceeds 400, preferably is 500 or more, more preferably is 1000 or more, and is 1200 or less, preferably is 1150 or less, more preferably is 1100 or less, and even more preferably is 1050 or less.

[0060] Examples of the second polycarbonate polyol include the above-mentioned crystalline polycarbonate polyol and the above-mentioned amorphous polycarbonate polyol. From the viewpoint of improving the stretchability (recovery force), heat resistance, and finger print recovery of the thermoplastic polyurethane resin in a balanced manner, the above-mentioned crystalline polycarbonate polyol is preferably used as the second polycarbonate polyol.

[0061] The number average molecular weight of the second polycarbonate polyol is 1800 or more, preferably 1850 or more, more preferably 1900 or more, and even more preferably 1950 or more. The number average molecular weight (polystyrene equivalent molecular weight) of the second polycarbonate polyol is, for example, 10000 or less, preferably 8000 or less, more preferably 5000 or less, even more preferably 3000 or less, and particularly preferably 2000 or less.

[0062] The polycarbonate polyol may contain, for example, only the first polycarbonate polyol. Alternatively, the polycarbonate polyol may contain, for example, only the second polycarbonate polyol. Preferably, the polycarbonate polyol contains the first polycarbonate polyol and the second polycarbonate polyol. When the polycarbonate polyol contains the first polycarbonate polyol and the second polycarbonate polyol, the content ratio thereof is appropriately set depending on the purpose and application.

[0063] For example, the first polycarbonate polyol may account for more than 0 mol%, preferably 40 mol% or more, of the total moles of the first polycarbonate polyol and the second polycarbonate polyol, and may account for less than 100 mol%, preferably 60 mol% or less, of the total moles of the first polycarbonate polyol and the second polycarbonate polyol.

[0064] Furthermore, the second polycarbonate polyol accounts for, for example, more than 0 mol%, preferably 40 mol% or more, based on the total moles of the first polycarbonate polyol and the second polycarbonate polyol, and for example, less than 100 mol%, preferably 60 mol% or less, based on the total moles of the first polycarbonate polyol and the second polycarbonate polyol.

[0065] The macropolyol may contain other macropolyols as optional components. The other macropolyols are macropolyols other than polycarbonate polyols.

[0066] Other macropolyols include, for example, polyether polyols, polyester polyols, polyurethane polyols, epoxy polyols, vegetable oil polyols, polyolefin polyols, acrylic polyols, and vinyl monomer-modified polyols. These can be used alone or in combination of two or more.

[0067] The content of the other macropolyols relative to the total amount of macropolyols is, for example, 50% by mass or less, preferably 30% by mass or less, more preferably 10% by mass or less, and particularly preferably 0% by mass.

[0068] That is, the content of the polycarbonate polyol is, for example, 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass, based on the total amount of the macropolyol. In other words, the macropolyol is particularly preferably composed of a polycarbonate polyol.

[0069] The number average molecular weight (polystyrene equivalent molecular weight) of the macropolyol exceeds 400, preferably 500 or more, more preferably 1000 or more. The number average molecular weight (polystyrene equivalent molecular weight) of the macropolyol is, for example, 10000 or less, preferably 8000 or less, more preferably 5000 or less, even more preferably 3000 or less, and particularly preferably 2000 or less.

[0070] The content of the macropolyol is, for example, 10 mol% or more, preferably 20 mol% or more, more preferably 30 mol% or more, based on the total amount of the macropolyol and the low molecular weight polyol. The content of the macropolyol is, for example, 95 mol% or less, preferably 70 mol% or less, more preferably 50 mol% or less, based on the total amount of the macropolyol and the low molecular weight polyol.

[0071] (2) Low molecular weight polyol Low-molecular-weight polyols are organic compounds that have two or more hydroxyl groups in the molecule and have a relatively low molecular weight. The term "relatively low molecular weight" refers to a number-average molecular weight of 400 or less.

[0072] The low-molecular-weight polyol includes, for example, a low-molecular-weight diol having 2 to 6 carbon atoms. The low-molecular-weight diol having 2 to 6 carbon atoms is a compound having 2 to 6 carbon atoms per molecule, two hydroxyl groups per molecule, and a molecular weight of 400 or less.

[0073] Examples of low-molecular-weight diols having 2 to 6 carbon atoms include alkanediols having 2 to 6 carbon atoms, etherdiols having 2 to 6 carbon atoms, and alkenediols having 2 to 6 carbon atoms. Examples of alkanediols having 2 to 6 carbon atoms include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol (1,4-BD), 1,3-butanediol, 1,2-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, and 2,2-dimethyl-1,3-propanediol. Examples of etherdiols having 2 to 6 carbon atoms include diethylene glycol, triethylene glycol, and dipropylene glycol. Examples of alkenediols having 2 to 6 carbon atoms include 1,4-dihydroxy-2-butene. These can be used alone or in combination.

[0074] The carbon number of the low molecular weight diol having 2 to 6 carbon atoms is 2 or more, preferably 3 or more. The carbon number of the low molecular weight diol having 2 to 6 carbon atoms is 6 or less, preferably 5 or less. The low molecular weight diol having 2 to 6 carbon atoms particularly preferably has 4 carbon atoms.

[0075] As the low molecular weight diol having 2 to 6 carbon atoms, preferably, an alkanediol having 2 to 6 carbon atoms is used, and more preferably, 1,4-butanediol is used.

[0076] The low-molecular-weight polyol may contain other low-molecular-weight polyols as needed. The other low-molecular-weight polyols are low-molecular-weight polyols other than low-molecular-weight diols having 2 to 6 carbon atoms. Examples of other low-molecular-weight polyols include low-molecular-weight diols having 7 or more carbon atoms and low-molecular-weight polyols having a valence of 3 or more. These may be used alone or in combination of two or more.

[0077] The content of the other low molecular weight polyols is, for example, 50% by mass or less, preferably 30% by mass or less, more preferably 10% by mass or less, and particularly preferably 0% by mass, relative to the total amount of low molecular weight polyols.

[0078] That is, the content of the low-molecular-weight diol having 2 to 6 carbon atoms is, for example, 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass, relative to the total amount of the low-molecular-weight polyol. In other words, the low-molecular-weight polyol particularly preferably consists of a low-molecular-weight diol having 2 to 6 carbon atoms.

[0079] The low-molecular-weight polyol has a molecular weight of, for example, 30 or more, or preferably 70 or more. The low-molecular-weight polyol has a molecular weight of 400 or less, or preferably 300 or less.

[0080] The content ratio of the low-molecular-weight polyol is appropriately set depending on the purpose and application, and preferably, the content ratio of the low-molecular-weight polyol is appropriately set so that the hard segment concentration described below falls within a desired range.

[0081] For example, the content of the low molecular weight polyol is, for example, 5 mol% or more, preferably 30 mol% or more, more preferably 50 mol% or more, based on the total amount of the macropolyol and the low molecular weight polyol. The content of the low molecular weight polyol is, for example, 90 mol% or less, preferably 80 mol% or less, more preferably 70 mol% or less, based on the total amount of the macropolyol and the low molecular weight polyol.

[0082] 3. Thermoplastic polyurethane resin As described above, the thermoplastic polyurethane resin is a reaction product of the raw material components, that is, the polyisocyanate component and the polyol component. In other words, the thermoplastic polyurethane resin is produced by reacting the polyisocyanate component and the polyol component (reaction step).

[0083] In the reaction step, the polyisocyanate component and the polyol component can be reacted by a known method, such as a one-shot method or a prepolymer method.

[0084] In the one-shot method, for example, a polyisocyanate component and a polyol component are reacted at once. In the prepolymer method, for example, a polyisocyanate component and a macropolyol are first reacted to synthesize an isocyanate-terminated prepolymer. Then, the isocyanate-terminated prepolymer is reacted with a low-molecular-weight polyol. From the viewpoint of improving various physical properties, the prepolymer method is preferred.

[0085] In the prepolymer method, first, a polyisocyanate component and a macropolyol are reacted to synthesize an isocyanate group-terminated prepolymer (prepolymer synthesis step).

[0086] In the prepolymer synthesis process, the polyisocyanate component and the macropolyol are mixed in a predetermined ratio, which is adjusted based on the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate group in the polyisocyanate component to the hydroxyl group in the macropolyol.

[0087] That is, the equivalent ratio of the isocyanate groups in the polyisocyanate component to the hydroxyl groups in the macropolyol (isocyanate groups / hydroxyl groups) is, for example, 1.3 or more, preferably 1.5 or more. Also, the equivalent ratio of the isocyanate groups in the polyisocyanate component to the hydroxyl groups in the chloropolyol (isocyanate groups / hydroxyl groups) is, for example, 20 or less, preferably 15 or less, more preferably 10 or less, and even more preferably 8 or less.

[0088] In terms of mass, the polyisocyanate component is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, more preferably 15 parts by mass or more, per 100 parts by mass of the macropolyol. Also, the polyisocyanate component is, for example, 150 parts by mass or less, preferably 100 parts by mass or less, more preferably 90 parts by mass or less, per 100 parts by mass of the macropolyol.

[0089] In the prepolymer synthesis step, the method for reacting the polyisocyanate component with the macropolyol is not particularly limited. Examples of the reaction method include bulk polymerization and solution polymerization.

[0090] In bulk polymerization, for example, a polyisocyanate component and a macropolyol are reacted under a nitrogen stream. The reaction temperature is, for example, 50°C or higher. The reaction temperature is, for example, 250°C or lower, preferably 200°C or lower. The reaction time is, for example, 0.5 hours or higher, preferably 1 hour or higher. The reaction time is, for example, 48 hours or lower, preferably 24 hours or lower.

[0091] In solution polymerization, the polyisocyanate component and the macropolyol are reacted in the presence of a known organic solvent. The reaction temperature is, for example, 50°C or higher. The reaction temperature is, for example, 120°C or lower, preferably 100°C or lower. The reaction time is, for example, 0.5 hours or higher, preferably 1 hour or higher. The reaction time is, for example, 48 hours or lower, preferably 24 hours or lower.

[0092] As a result, an isocyanate group-terminated prepolymer is obtained as a reaction product liquid of the polyisocyanate component and the macropolyol.

[0093] In the prepolymer synthesis step, a known urethanization catalyst may be added as needed. The amount of the urethanization catalyst added is appropriately determined depending on the purpose and application.

[0094] In the prepolymer synthesis step, the isocyanate-terminated prepolymer may be purified by a known method, such as distillation or extraction, if necessary.

[0095] Next, in this method, the isocyanate group-terminated prepolymer is reacted with a low-molecular-weight polyol to obtain a thermoplastic polyurethane resin (chain extension step).

[0096] In the chain extension step, the isocyanate-terminated prepolymer and the low-molecular-weight polyol are mixed in a predetermined ratio, which is adjusted based on the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate groups in the isocyanate-terminated prepolymer to the hydroxyl groups in the low-molecular-weight polyol.

[0097] That is, the equivalent ratio of the isocyanate groups in the isocyanate-terminated prepolymer to the hydroxyl groups in the low-molecular-weight polyol (isocyanate groups / hydroxyl groups) is, for example, 0.75 or more, preferably 0.9 or more.Further, the equivalent ratio of the isocyanate groups in the isocyanate-terminated prepolymer to the hydroxyl groups in the low-molecular-weight polyol (isocyanate groups / hydroxyl groups) is, for example, 1.3 or less, preferably 1.1 or less.

[0098] In terms of mass, the amount of the low-molecular-weight polyol relative to 100 parts by mass of the isocyanate group-terminated prepolymer is, for example, 1.0 part by mass or more, preferably 2.5 parts by mass or more, more preferably 3.5 parts by mass or more, even more preferably 4.5 parts by mass or more, and particularly preferably 5.5 parts by mass or more, and for example, 15.0 parts by mass or less, preferably 10.0 parts by mass or less, more preferably 9.0 parts by mass or less.

[0099] In the chain extension step, the method for reacting the isocyanate-terminated prepolymer with the low-molecular-weight polyol is not particularly limited, and examples of the reaction method include the above-mentioned bulk polymerization and solution polymerization.

[0100] As a result, a thermoplastic polyurethane resin is obtained as a reaction product of the isocyanate group-terminated prepolymer and the low-molecular-weight polyol.

[0101] In the chain extension step, a known urethanization catalyst may be added as needed. The amount of the urethanization catalyst added is appropriately determined depending on the purpose and application.

[0102] The thermoplastic polyurethane resin may contain known additives as needed. Examples of additives include antioxidants, heat stabilizers, UV absorbers, light stabilizers, hydrolysis inhibitors, dyes, plasticizers, antiblocking agents, surface modifiers, lubricants, mold release agents, pigments, fillers, rust inhibitors, and bulking agents. These may be used alone or in combination of two or more. The amount and timing of addition of the additives are appropriately determined depending on the purpose and application.

[0103] The thermoplastic polyurethane resin is subjected to an aging treatment as needed (aging step). In the aging step, the above-mentioned thermoplastic polyurethane resin (unaged product) is subjected to an aging treatment. As a result, an aged product of the thermoplastic polyurethane resin is obtained.

[0104] The aging temperature is, for example, 50°C or higher, preferably 60°C or higher, and more preferably 70°C or higher. The aging temperature is, for example, 100°C or lower, and preferably 90°C or lower. The aging time is, for example, 3 days or longer, preferably 4 days or longer, more preferably 5 days or longer, and even more preferably 6 days or longer. The aging time is, for example, 10 days or shorter, preferably 9 days or shorter, and more preferably 8 days or shorter.

[0105] In view of heat resistance, the hard segment concentration of the thermoplastic polyurethane resin is, for example, 18 mass % or more, preferably 20 mass % or more, and more preferably 22 mass % or more. Furthermore, from the viewpoint of elasticity properties, the hard segment concentration of the thermoplastic polyurethane resin is, for example, 35% by mass or less, preferably 30% by mass or less, and more preferably 25% by mass or less.

[0106] When the hard segment concentration of the thermoplastic polyurethane resin is within the above range, both finger print recovery property and heat resistance can be achieved particularly well.

[0107] Specifically, in the thermoplastic polyurethane resin described above, the polyisocyanate component contains 1,4-bis(isocyanatomethyl)cyclohexane and 1,3-bis(isocyanatomethyl)cyclohexane. The crystallinity of 1,3-bis(isocyanatomethyl)cyclohexane is lower than that of 1,4-bis(isocyanatomethyl)cyclohexane. Therefore, when the polyisocyanate component contains 1,4-bis(isocyanatomethyl)cyclohexane and 1,3-bis(isocyanatomethyl)cyclohexane, the crystallinity of the thermoplastic polyurethane resin is relatively lower than when the polyisocyanate component contains only 1,4-bis(isocyanatomethyl)cyclohexane. As a result, the thermoplastic polyurethane resin exhibits excellent fingerprint recovery. On the other hand, when the crystallinity of the thermoplastic polyurethane resin is relatively low, the heat resistance of the thermoplastic polyurethane resin may be reduced. In such cases, adjusting the hard segment concentration within a predetermined range prevents a decrease in the heat resistance of the thermoplastic polyurethane resin. That is, when the hard segment concentration is within the above range, the thermoplastic polyurethane resin can achieve both excellent fingertip recovery and heat resistance.

[0108] The concentration of the hard segment (the hard segment formed by the reaction of the polyisocyanate component with the low-molecular-weight polyol) of the thermoplastic polyurethane resin can be calculated by a known method, for example, from the blending ratio (charge) of each component.

[0109] More specifically, when a prepolymer method is used, the hard segment concentration can be calculated from the formulation (charge) of each component using the following formula:

[0110] [Low molecular weight polyol (g) + (Low molecular weight polyol (g) / Molecular weight of low molecular weight polyol (g / mol)) × Average molecular weight of polyisocyanate component (g / mol)] ÷ (Polyisocyanate component (g) + Total mass of polyol component (g)) × 100

[0111] The raw material components of the thermoplastic polyurethane resin contain a predetermined ratio of 1,4-bis(isocyanatomethyl)cyclohexane, a crystalline polycarbonate polyol, and a polyol component containing a low-molecular-weight polyol.

[0112] 1,4-bis(isocyanatomethyl)cyclohexane has relatively high crystallinity. Low-molecular-weight polyols form hard segments and improve crystallinity. Crystalline polycarbonate polyols have relatively high crystallinity.

[0113] The raw material components also contain 1,3-bis(isocyanatomethyl)cyclohexane, which has relatively low crystallinity.

[0114] In the raw material components, the ratio of 1,4-bis(isocyanatomethyl)cyclohexane to 1,3-bis(isocyanatomethyl)cyclohexane is adjusted to fall within a predetermined range.

[0115] In other words, the crystallinity of the polyurethane structure is adjusted by the raw material components, which gives the thermoplastic polyurethane resin a good balance of elasticity (rebound force), heat resistance, and finger print recovery.

[0116] Furthermore, if the crystallinity of the polyurethane structure is adjusted as described above, the thermoplastic polyurethane resin also has excellent bloom resistance and melting properties.

[0117] Therefore, the thermoplastic polyurethane resin can be suitably used in the production of various molded articles. That is, the thermoplastic polyurethane resin can be molded by a known molding method to obtain a molded article containing the thermoplastic polyurethane resin.

[0118] Examples of molding methods include thermal compression molding, injection molding, extrusion molding, cut molding, melt spinning molding, and 3D printer molding. These can be used alone or in combination of two or more.

[0119] A preferred molding method is extrusion molding. In extrusion molding, for example, a thermoplastic polyurethane resin is first molded into pellets of the thermoplastic polyurethane resin. The thermoplastic polyurethane resin pellets are then subjected to secondary molding to obtain a molded product of a desired shape.

[0120] Examples of the shape of the molded product include film, sheet, plate, fiber, strand, pipe, hollow, and box shapes. These may be used alone or in combination of two or more. A preferred shape of the molded product is film.

[0121] In other words, a preferable example of the molded article is a film containing a thermoplastic polyurethane resin. Because such a film contains the above-mentioned thermoplastic polyurethane resin, it has a good balance of fingertip recovery, stretchability (recovery force), and heat resistance.

[0122] Therefore, the above film can be suitably used in fields where the various physical properties mentioned above are required. More specifically, the above film can be suitably used, for example, as a base film for various protective films. The protective film is not particularly limited, but examples thereof include a paint protection film (PPF), a protective film for automotive interior materials, a protective film for wind power generator blades, and a protective film for glass. A paint protection film is preferred. Paint protection films are used to protect the painted surfaces of various products in various industrial fields such as the automotive industry.

[0123] More specifically, paint protection films (PPF) are applied to the painted surfaces of various products (e.g., automobiles and motorcycles), thereby protecting the surfaces of the various products.

[0124] The paint protection film (PPF) comprises at least a film containing the above-mentioned thermoplastic polyurethane resin. For example, the paint protection film (PPF) is a laminated film comprising a release layer, an adhesive layer disposed on at least one side of the release layer, and a base film layer disposed on at least one side of the adhesive layer. More specifically, the paint protection film (PPF) comprises, for example, a release layer containing a polyester resin, an acrylic adhesive layer disposed on the release layer, and a base film layer disposed on the acrylic adhesive layer. The paint protection film (PPF) may also further comprise a surface protection layer disposed on the base film layer.

[0125] The base film layer contains the above-mentioned film. That is, a film containing the above-mentioned thermoplastic polyurethane resin is used as the base film layer of the paint protection film (PPF). This gives the paint protection film (PPF) excellent stretchability (recovery force), heat resistance, and finger print recovery. Therefore, the paint protection film (PPF) can provide excellent protection for various products (automobiles, motorcycles, etc.).

[0126] Furthermore, the above-mentioned film (e.g., base film layer) may be colored by any method. That is, the above-mentioned film (e.g., base film layer) may be a color film. For example, when the base film layer of the protective film is a color film, the protective film can protect various products as described above and can also color various products. More specifically, for example, when the base film of a paint protection film used on an automobile is a color film, the paint protection film can protect the painted surface of the automobile and can easily change the body color of the automobile.

[0127] The thermoplastic polyurethane resin, film, and paint protection film described above can be suitably used in various industrial fields where stretchability (recovery force), heat resistance, and finger mark recovery are required. In particular, the thermoplastic polyurethane resin, film, and paint protection film described above are suitably used in the paint protection field for protecting the painted surfaces of vehicles (e.g., automobiles and motorcycles). [Example]

[0128] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited thereto. Note that "parts" and "%" are by mass unless otherwise specified. Furthermore, specific numerical values ​​such as blending ratios (content ratios), physical property values, and parameters used in the following description can be substituted with the corresponding upper limit values ​​(numeric values ​​defined as "equal to or less than") or lower limit values ​​(numeric values ​​defined as "equal to or more than" or "exceeding") of the blending ratios (content ratios), physical property values, and parameters described in the above "Modes for Carrying Out the Invention."

[0129] 1) Raw materials <Polyisocyanate component (a)> 1,4-H6XDI: 1,4-bis(isocyanatomethyl)cyclohexane obtained in accordance with the description of Production Example 3 of WO 2019 / 069802. Trans isomer: 86 mol %; cis isomer: 14 mol %. 1,3-H6XDI: 1,3-bis(isocyanatomethyl)cyclohexane, trade name Takenate 600, manufactured by Mitsui Chemicals, Inc.

[0130] <Macropolyol (b)> b-1) PCD1000: Number average molecular weight (Mn) 1000, crystalline polycarbonate diol, product name ETERNACOLL UH-100W, average number of hydroxyl groups 2, manufactured by Ube Industries b-2) PCD2000: Number average molecular weight (Mn) 2000, crystalline polycarbonate diol, product name ETERNACOLL UH-200W, average number of hydroxyl groups 2, manufactured by Ube Industries b-3) Liquid PCD1000: number average molecular weight (Mn) 1000, amorphous polycarbonate diol, trade name ETERNACOLL UP-100, average number of hydroxyl groups 2, manufactured by Ube Industries, Ltd. b-4) Liquid PCD2000: number average molecular weight (Mn) 2000, amorphous polycarbonate diol, trade name ETERNACOLL UP-200, average number of hydroxyl groups 2, manufactured by Ube Industries, Ltd. b-5) PCL1000: number average molecular weight (Mn) 1000, polycaprolactone diol, trade name PLACCEL 210N, average number of hydroxyl groups 2, manufactured by Daicel Corporation. b-6) PCL2000: Polycaprolactone diol, number average molecular weight (Mn) 2000, trade name PLACCEL 220N, average number of hydroxyl groups 2, manufactured by Daicel Corporation

[0131] <Low molecular weight polyol (c)> 1,4-BD: 1,4-butanediol, manufactured by Mitsubishi Chemical Corporation

[0132] 2) Thermoplastic polyurethane resin Example 1 10, Reference Examples 11-12, Examples 13- 14 and Comparative Examples 1 to 14 According to the formulations shown in Tables 1 to 4, thermoplastic polyurethane resins and sheets were obtained.

[0133] More specifically, first, macropolyol (b) whose temperature had been adjusted to 80°C in advance was weighed. Macropolyol (b) was stirred in an oil bath at 80°C under a nitrogen atmosphere for 1 hour. Next, the following additives were added to macropolyol (b), and the mixture was stirred in an oil bath at 80°C under a nitrogen atmosphere for 1 hour.

[0134] Irganox 245 (BASF heat stabilizer) 0.3 parts by mass Tinuvin 571 (UV absorber manufactured by BASF) 0.4 parts by mass 0.1 parts by weight of Adeka Stab LA-72 (HALS manufactured by ADEKA Corporation) (The above figures are based on 100 parts by mass of the total amount of polyisocyanate component, macropolyol, and low molecular weight polyol.)

[0135] Next, polyisocyanate component (a) was added to the mixture of macropolyol (b) and additives in the proportions shown in Tables 1 to 4. Furthermore, a solution of stannous octoate (solvent: diisononyl adipate, concentration: 4% by mass) as a urethane-forming catalyst was added at a ratio of 5 ppm to the mixture. Next, the mixture was stirred and mixed in an oil bath at 80°C for 5 minutes to allow the reaction to occur. This resulted in an isocyanate-terminated prepolymer (prepolymer synthesis step).

[0136] Next, the low-molecular-weight polyol (c) adjusted to a temperature of 80°C was added to the isocyanate-terminated prepolymer, and the mixture was stirred and mixed for 3 to 20 minutes.

[0137] The amount of low-molecular-weight polyol (c) added was adjusted so that the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate group in the isocyanate-terminated prepolymer to the hydroxyl group in the low-molecular-weight polyol (c) was 1.00. The tin octoate solution was added appropriately while monitoring the heat generation rate.

[0138] The reaction product liquid was then poured into a Teflon (registered trademark) tray whose temperature had been adjusted to 150°C, and reacted at 150°C for 2 hours, and then further reacted at 100°C for 20 hours (chain extension step), thereby obtaining a thermoplastic polyurethane resin.

[0139] Next, the thermoplastic polyurethane resin (unaged product) was taken out and cut into cubes using a bale cutter. The cube-shaped thermoplastic polyurethane resin was then pulverized using a pulverizer. This resulted in pulverized pellets.

[0140] The crushed pellets were then aged in an oven at 80° C. for 7 days and dried under reduced pressure in vacuum at 23° C. for 12 hours, thereby obtaining an aged thermoplastic polyurethane resin.

[0141] The aged thermoplastic polyurethane resin was then molded using a single-screw extruder (model: SZW40-28MG, manufactured by Technobel Co., Ltd.) to obtain pellets (primary molded product). The extruder screw rotation speed was 30 rpm, and the cylinder temperature was 150°C to 250°C. The thermoplastic polyurethane resin pellets were dried under reduced pressure at 80°C for 12 hours.

[0142] The pellets were then molded using a single-screw extruder (model: SZW40-28MG, manufactured by Technobel Co., Ltd.) to obtain a film (secondary molded product). The screw rotation speed of the extruder was 20 rpm, and the cylinder temperature was 150°C to 250°C. The thermoplastic polyurethane resin film was used in the following evaluation tests.

[0143] The hard segment concentration of the thermoplastic polyurethane resin was calculated using the following formula: [Low-molecular-weight polyol (g) + (Low-molecular-weight polyol (g) / Molecular weight of low-molecular-weight polyol (g / mol)) × Average molecular weight of polyisocyanate component (g / mol)] ÷ (Polyisocyanate component (g) + Total mass of polyol component (g)) × 100

[0144] 4) Evaluation <Hardness (shoreA)> The Shore A hardness of the thermoplastic polyurethane resin film was measured in accordance with JIS K 7312 (1996).

[0145] <Stretchability: Return rate (shape recovery rate)> The thermoplastic polyurethane resin film was set in a universal testing machine Model 205N (manufactured by Intesco, gauge length 80 mm, tensile speed 500 ml / min), stretched to 60% (48 mm) of the gauge length, and then released.

[0146] 15 seconds after release, the gauge length was measured and the film's return rate was determined. The film's return rate is the ratio (%) of the film's length before stretching to the film's length after stretching. A higher film return rate (closer to 100%) indicates a higher return rate (shape recovery rate).

[0147] The criteria for determining the stretchability properties are as follows: ◎: Return rate 98.5% or more 〇: Return rate is 97.5% or more but less than 98.5% △: Return rate 97.0% or more but less than 97.5% ×: Return rate less than 97.0%

[0148] <Fingerprint Recovery> A 20 mm diameter center punch was placed on the surface of a thermoplastic polyurethane resin film, and the punch was pushed 14 mm toward the film, causing a convex deformation. The film was then released from the punch. After 10 minutes, the height of the convex part (punch mark) on the film was measured.

[0149] The convex portion remaining rate of the film was also calculated. The convex portion remaining rate is the ratio (%) of the height of the convex portion after release to the height of the convex portion before release. A lower convex portion remaining rate (closer to 0%) indicates a higher finger mark recovery rate.

[0150] The criteria for determining finger print recovery are as follows: ◎: Less than 10% of the convex parts remain ○: Remaining convex parts are 10% or more and less than 17% △: Remaining convex portion rate is 17% or more and less than 19% ×: Remaining convex portion rate 19% or more

[0151] <Heat resistance: storage modulus (E')> The dynamic viscoelasticity spectrum of the thermoplastic polyurethane resin film was measured using a dynamic viscoelasticity measuring device (IT Measurement Control, Model: DVA-220) under the following conditions: measurement temperature -100°C to 250°C, heating rate 5°C / min, tensile mode, gauge length 20 mm, static / dynamic stress ratio 1.8, and measurement frequency 10 Hz.

[0152] Then, the storage modulus E' at 80° C. was measured. It is considered that the higher the E', the better the heat resistance.

[0153] The criteria for judging heat resistance are as follows. ◎: Storage modulus E' (80℃) 20 × 10 6 MPa or more ○: Storage modulus E' (80℃) 10 × 10 6 MPa or more 20 x 10 6 Less than MPa ×: Storage modulus E' (80°C) 10 × 10 6 Less than MPa

[0154] <Bloom resistance> The thermoplastic polyurethane resin film was stored at 30°C and a relative humidity of 80% for 35 days, after which the haze of the film was measured using a HAZE METER NDH-5000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

[0155] <Melting enthalpy (unit: J / g)> Measurements were carried out using a differential scanning calorimeter (DSC7000X, manufactured by Hitachi High-Tech Science) as follows.

[0156] That is, about 10 mg of thermoplastic polyurethane resin was placed in an aluminum pan. This aluminum pan was covered with a cover and crimped to prepare a measurement sample. Similarly, alumina was collected and used as a reference sample.

[0157] After setting the sample and reference in their designated positions in the cell, the sample was cooled from 20°C to -100°C at a rate of 10°C / min under a nitrogen flow of 30 NmL / min, held at that temperature for 5 minutes, then heated to 270°C at a rate of 10°C / min, and then cooled to -70°C at a rate of 10°C / min.

[0158] Among the peaks appearing during the temperature rise from -100°C to 270°C, the peak temperature of the endothermic peak (melting peak) at 160°C or higher and the heat quantity (enthalpy change) (J / g) of that peak were measured.

[0159] [Table 1]

[0160] [Table 2]

[0161] [Table 3]

[0162] [Table 4]

[0163] The above invention is provided as an exemplary embodiment of the present invention, but it is merely an example and should not be interpreted as being limiting. Modifications of the present invention that are obvious to those skilled in the art are intended to be included in the scope of the following claims. [Industrial Applicability]

[0164] The thermoplastic polyurethane resin, film and paint protection film of the present invention are suitably used in the field of paint protection for protecting the painted surfaces of vehicles.

Claims

1. a thermoplastic polyurethane resin containing a reaction product of a polyisocyanate component and a polyol component, The polyisocyanate component is 1,4-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane and Including, the polyol component includes a polycarbonate polyol and a low molecular weight polyol; The polycarbonate polyol comprises a crystalline polycarbonate polyol that is solid at 25°C, Relative to the total amount of 1,4-bis(isocyanatomethyl)cyclohexane and 1,3-bis(isocyanatomethyl)cyclohexane, The proportion of 1,4-bis(isocyanatomethyl)cyclohexane is 50 mol % or more and 90 mol % or less, the proportion of 1,3-bis(isocyanatomethyl)cyclohexane is 10 mol % or more and 50 mol % or less, The polycarbonate polyol is a first polycarbonate polyol having a number average molecular weight of 1,200 or less; a second polycarbonate polyol having a number average molecular weight of 1800 or more; A thermoplastic polyurethane resin comprising:

2. The thermoplastic polyurethane resin according to claim 1 , wherein the polycarbonate polyol consists of the crystalline polycarbonate polyol.

3. 2. The thermoplastic polyurethane resin according to claim 1, wherein the hard segment concentration of the thermoplastic polyurethane resin is 18% by mass or more and 35% by mass or less.

4. The thermoplastic polyurethane resin according to claim 1 A film characterized by:

5. a release layer; an adhesive layer disposed on at least one surface of the release layer; a base film layer disposed on at least one surface of the adhesive layer; A paint protection film, wherein the base film layer comprises the film of claim 4.

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