Polycarbonate diol

Abstract

Provided is a polycarbonate diol that has excellent stability during high-temperature storage. [Solution] A polycarbonate diol containing a repeating unit represented by specific formula (A) and containing a terminal hydroxyl group, wherein the repeating units of specific formula (A) are repeating units represented by specific formulas (b) and (c), the amount of repeating units represented by specific formula (b) is 10 to 90 mol % based on the total number of repeating units represented by specific formula (A), and 90 mol % or more of the total number of terminal groups are terminal groups represented by specific formulas (be) and / or (ce), and the polycarbonate diol satisfies the following formula (i-2): (NMR calculation (ce) / (be))>(alkaline hydrolysis HMD / LMD) (i-2)

Description

[Technical Field]

[0001] The present invention relates to a polycarbonate diol. [Background technology]

[0002] Conventionally, it has been proposed to use polycarbonate diols, which can impart excellent heat resistance, weather resistance, hydrolysis resistance, oil resistance, and chemical resistance, as soft segments used in thermoplastic elastomers such as polyurethanes, urethane-based, ester-based, and amide-based elastomers.

[0003] As such polycarbonate diol, a polycarbonate diol using 1,6-hexanediol alone as the diol component is generally used, but such polycarbonate diol has a problem in that it is crystalline and therefore solid at room temperature, making it difficult to handle.

[0004] In order to solve these problems, it has been proposed to produce a polycarbonate diol using two or more types of diols. For example, Patent Document 1 discloses a polycarbonate diol using 1,4-butanediol and 1,6-hexanediol as diol components. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5123950 Summary of the Invention [Problem to be solved by the invention]

[0006] However, polycarbonate diols are often solids or viscous liquids at room temperature. Therefore, they are sometimes stored at high temperatures to improve their handling. In this case, there is a problem that the reactivity of the polycarbonate diol immediately after production changes over time when stored at high temperatures. Even with the polycarbonate diol described in Patent Document 1, there is still room for improvement in stability during high-temperature storage.

[0007] Therefore, an object of the present invention is to provide a polycarbonate diol that has excellent stability during high-temperature storage. [Means for solving the problem]

[0008] As a result of extensive research to solve the above problems, the present inventors have found that polycarbonate diols having a specific structure have excellent stability during high-temperature storage, leading to the completion of the present invention.

[0009] That is, the present invention is configured as follows. [1] A polycarbonate diol containing a repeating unit represented by the following formula (A) and having a terminal hydroxyl group: 90 to 100 mol % of the repeating units of formula (A) are repeating units represented by the following formula (B) and / or (C): the amount of the repeating unit represented by formula (B) is 10 to 90 mol % based on the total amount of the repeating unit represented by formula (A); 90 mol % or more of the total amount of terminal groups are terminal groups represented by the following formula (BE) and / or (CE), A polycarbonate diol that satisfies the following formula (i): [ka] (In formula (A), R represents a divalent aliphatic or alicyclic hydrocarbon having 2 to 15 carbon atoms.) [ka] [ka] [ka] (In formula (BE), A represents formula (A).) [ka] (In formula (CE), A represents formula (A).) (NMR calculation (CE) / (BE))>(alkaline hydrolyzed HDL / BDL) (i) (In formula (i), NMR calculated (CE) / (BE) is the molar ratio of the end group represented by formula (CE) to the end group represented by formula (BE) measured by nuclear magnetic resonance (NMR), and alkaline hydrolyzed HDL / BDL is the molar ratio of 1,6-hexanediol (HDL) to 1,4-butanediol (BDL) obtained by alkaline hydrolysis of polycarbonate diol.) [2] The polycarbonate diol according to [1], wherein the amount of the repeating unit represented by formula (B) is 30 to 80 mol % based on the total amount of the repeating unit represented by formula (A). [3] The polycarbonate diol according to [1], wherein the amount of the repeating unit represented by formula (B) is 30 to 70 mol % based on the total amount of the repeating unit represented by formula (A). [4] The polycarbonate diol according to [1], wherein the amount of the repeating unit represented by formula (B) is 40 to 60 mol % based on the total amount of the repeating unit represented by formula (A). [5] A polycarbonate diol containing a repeating unit represented by the following formula (A) and having a terminal hydroxyl group: The repeating units of formula (A) are repeating units represented by the following formulas (b) and (c): the amount of the repeating unit represented by formula (b) is 10 to 90 mol % based on the total amount of the repeating unit represented by formula (A); 90 mol % or more of the total amount of terminal groups are terminal groups represented by the following formula (be) and / or (ce), A polycarbonate diol satisfying the following formula (i-2): [ka] (In formula (A), R represents a divalent aliphatic or alicyclic hydrocarbon having 2 to 15 carbon atoms.) [ka] (In formula (b), R 1 represents a divalent aliphatic or alicyclic hydrocarbon having 2 to 4 carbon atoms. [ka] (In formula (c), R 2 represents a divalent aliphatic or alicyclic hydrocarbon having 5 to 15 carbon atoms. [ka] (In formula (be), A represents formula (A), and R 11 represents a divalent aliphatic or alicyclic hydrocarbon having 2 to 4 carbon atoms. [ka] (In formula (ce), A represents formula (A), and R 22 represents a divalent aliphatic or alicyclic hydrocarbon having 5 to 15 carbon atoms. (NMR calculation (ce) / (be))>(alkaline hydrolysis HMD / LMD) (i-2) (In formula (i-2), NMR calculated (ce) / (be) is the molar ratio of the end group represented by formula (ce) to the end group represented by formula (be) measured by nuclear magnetic resonance (NMR), and alkaline hydrolysis HMD / LMD is the molar ratio of the aliphatic or alicyclic diol (HMD) having 5 to 15 carbon atoms to the aliphatic or alicyclic diol (LMD) having 2 to 4 carbon atoms, both obtained by alkaline hydrolysis of polycarbonate diol.) [6] The polycarbonate diol according to [5], wherein the amount of the repeating unit represented by formula (b) is 30 to 80 mol % based on the total amount of the repeating unit represented by formula (A). [7] The polycarbonate diol according to [5], wherein the amount of the repeating unit represented by formula (b) is 30 to 70 mol % based on the total amount of the repeating unit represented by formula (A). [8] The polycarbonate diol according to [5], wherein the amount of the repeating unit represented by formula (b) is 40 to 60 mol % based on the total amount of the repeating unit represented by formula (A). [9] R in formula (b) 1 is a divalent aliphatic hydrocarbon group having 2 to 4 carbon atoms, and R in formula (be) 11 The polycarbonate diol according to any one of [5] to [8], wherein is a divalent aliphatic hydrocarbon group having 2 to 4 carbon atoms.

[10] R in formula (c) 2 is a divalent aliphatic hydrocarbon group having 6 to 10 carbon atoms, and R in formula (ce) 22 The polycarbonate diol according to any one of [5] to [9], wherein is a divalent aliphatic hydrocarbon group having 6 to 10 carbon atoms.

[11] A method for storing the polycarbonate diol according to any one of [1] to

[10] , wherein the polycarbonate is stored in a state where it has fluidity.

[12] The storage method according to

[11] , comprising a step of heating or maintaining the temperature of the polycarbonate at 50°C or higher during storage. [Effects of the Invention]

[0010] According to the present invention, a polycarbonate diol having excellent stability during high-temperature storage can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. Note that the present invention is not limited to the following description, and various modifications can be made within the scope of the gist of the present invention.

[0012] [Polycarbonate diol] The polycarbonate diol of this embodiment includes the polycarbonate diol of the first embodiment and the polycarbonate diol of the second embodiment.

[0013] [Polycarbonate diol of the first embodiment] The polycarbonate diol of the first embodiment is a polycarbonate diol containing a repeating unit represented by the following formula (A) and containing a terminal hydroxyl group, in which 90 to 100 mol % of the repeating units of formula (A) are repeating units represented by the following formula (B) and / or (C), the amount of repeating units represented by formula (B) is 10 to 90 mol % relative to the total repeating units represented by formula (A), and 90 mol % or more of the total number of terminal groups are terminal groups represented by the following formula (BE) and / or (CE), and satisfies the following formula (i). [ka] (R in formula (A) represents a divalent aliphatic or alicyclic hydrocarbon having 2 to 15 carbon atoms.) [ka] [ka] [ka] (A in formula (BE) means formula (A).) [ka] (A in formula (CE) means formula (A).)

[0014] (NMR calculation (CE) / (BE))>(alkaline hydrolyzed HDL / BDL) (i) (In formula (i), NMR calculated (CE) / (BE) is the molar ratio of the end group represented by formula (CE) to the end group represented by formula (BE) measured by nuclear magnetic resonance (NMR), and alkaline hydrolyzed HDL / BDL is the molar ratio of 1,6-hexanediol (HDL) to 1,4-butanediol (BDL) obtained by alkaline hydrolysis of polycarbonate diol.)

[0015] In this embodiment, the amounts of terminal groups represented by formula (CE) and formula (BE), and the amounts of 1,6-hexanediol (HDL) and 1,4-butanediol (BDL) in the alkaline hydrolysate can be measured by the method described in the Examples below.

[0016] In the polycarbonate diol of the first embodiment, the amount of repeating units represented by formula (B) is 10 to 90 mol%, preferably 30 to 80 mol%, more preferably 30 to 70 mol%, and even more preferably 40 to 60 mol%, based on the total amount of repeating units represented by formula (A). When the ratio is 10 mol% or more and 90 mol% or less, the resulting polycarbonate diol becomes liquid and is easy to handle. Furthermore, in the polycarbonate diol of the first embodiment, 90 mol% or more of the total number of terminal groups are terminal groups represented by formula (BE) and / or (CE), and by satisfying formula (i), the polycarbonate diol has excellent stability during high-temperature storage.

[0017] (Alkaline hydrolyzed HDL / BDL) Alkaline hydrolysis HDL / BDL refers to the molar ratio (HDL / BDL) of 1,6-hexanediol (HDL) to 1,4-butanediol (BDL) obtained by alkaline hydrolysis of polycarbonate diol. The range of alkaline hydrolysis HDL / BDL is preferably 1 / 9 to 9 / 1, more preferably 2 / 8 to 7 / 3, even more preferably 2 / 8 to 6 / 4, and particularly preferably 4 / 6 to 6 / 4.

[0018] (NMR calculation (CE) / (BE)) The NMR calculated (CE) / (BE) is the molar ratio ((CE) / (BE)) of the terminal group represented by formula (CE) to the terminal group represented by formula (BE) measured by nuclear magnetic resonance (NMR). The NMR calculated (CE) / (BE) is preferably in the range of 9.00 to 0.10, more preferably 2.50 to 0.20, still more preferably 2.0 to 0.20, and particularly preferably 2.0 to 0.5.

[0019] The formula (i) satisfies (NMR calculated (CE) / (BE))>(alkali hydrolyzed HDL / BDL), but it is more preferable that the following formula (ii) is satisfied. (NMR calculated (CE) / (BE)) - (alkaline hydrolyzed HDL / BDL) ≥ 0.001 (ii)

[0020] In formula (ii), "(NMR calculated (CE) / (BE)) - (alkali hydrolyzed HDL / BDL)" is preferably 0.005 or more, more preferably 0.01 or more, and even more preferably 0.15 or more. The upper limit of "(NMR calculated (CE) / (BE)) - (alkali hydrolyzed HDL / BDL)" in formula (ii) is not particularly limited, but is, for example, 9 or less.

[0021] [Polycarbonate diol of second embodiment] The polycarbonate diol of the second embodiment will be described below. The polycarbonate diol of the second embodiment is a generalized version of the polycarbonate diol of the first embodiment described above.

[0022] That is, the polycarbonate diol of the second embodiment is a polycarbonate diol containing a repeating unit represented by the following formula (A) and containing a terminal hydroxyl group, wherein the repeating units of formula (A) are repeating units represented by the following formulas (b) and (c), the amount of repeating units represented by formula (b) is 10 to 90 mol % based on the total repeating units represented by formula (A), 90 mol % or more of the total number of terminal groups are terminal groups represented by the following formula (be) and / or (ce), and satisfies the following formula (i-2). [ka] (In formula (A), R represents a divalent aliphatic or alicyclic hydrocarbon having 2 to 15 carbon atoms.) [ka] (In formula (b), R 1 represents a divalent aliphatic or alicyclic hydrocarbon having 2 to 4 carbon atoms. [ka] (In formula (c), R 2 represents a divalent aliphatic or alicyclic hydrocarbon having 5 to 15 carbon atoms. [ka] (In formula (be), A represents formula (A), and R 11 represents a divalent aliphatic or alicyclic hydrocarbon having 2 to 4 carbon atoms. [ka] (In formula (ce), A represents formula (A), and R 22 represents a divalent aliphatic or alicyclic hydrocarbon having 5 to 15 carbon atoms.

[0023] (NMR calculation (ce) / (be))>(alkaline hydrolysis HMD / LMD) (i-2) (In formula (i-2), NMR calculated (ce) / (be) is the molar ratio of the end group represented by formula (ce) to the end group represented by formula (be) measured by nuclear magnetic resonance (NMR), and alkaline hydrolysis HMD / LMD is the molar ratio of the aliphatic or alicyclic diol (HMD) having 5 to 15 carbon atoms to the aliphatic or alicyclic diol (LMD) having 2 to 4 carbon atoms, both obtained by alkaline hydrolysis of polycarbonate diol.)

[0024] R in formula (b) 1 is preferably a divalent aliphatic hydrocarbon group having 2 to 4 carbon atoms, and R 11 is preferably a divalent aliphatic hydrocarbon group having 2 to 4 carbon atoms. 2 is preferably a divalent aliphatic hydrocarbon group having 6 to 10 carbon atoms, and R 22 is preferably a divalent aliphatic hydrocarbon group having 6 to 10 carbon atoms.

[0025] In formula (i-2), the aliphatic or alicyclic diol (HMD) having 5 to 15 carbon atoms is not particularly limited, and examples thereof include 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nanodiol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 2-methyl-1,8-octanediol, 2-ethyl-1,6-hexanediol, 3-methyl-1,5-pentanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and 2-bis(4-hydroxycyclohexyl)-propane.

[0026] In formula (i-2), the aliphatic or alicyclic diol (LMD) having 2 to 4 carbon atoms is not particularly limited, but examples thereof include ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 2-methyl-1,3-propanediol.

[0027] In this embodiment, the amounts of terminal groups represented by formula (ce) and formula (be), and the amounts of HMD and LMD in the alkaline hydrolysate can be measured by the method described in the examples below.

[0028] In the polycarbonate diol of this embodiment, the amount of repeating units represented by formula (b) is 10 to 90 mol%, preferably 30 to 80 mol%, more preferably 30 to 70 mol%, and even more preferably 40 to 60 mol%, based on the total amount of repeating units represented by formula (A). When this ratio is 10 mol% or more and 90 mol% or less, the resulting polycarbonate diol becomes liquid and is easy to handle. Furthermore, in the polycarbonate diol of this embodiment, 90 mol% or more of the total number of terminal groups are terminal groups represented by formula (be) and / or (ce), and by satisfying formula (i-2), the polycarbonate diol has excellent stability during high-temperature storage.

[0029] (Alkaline hydrolysis HMD / LMD) Alkaline hydrolysis HMD / LMD refers to the molar ratio (HMD / LMD) of a divalent aliphatic or alicyclic diol (HMD) having 5 to 15 carbon atoms to a divalent aliphatic or alicyclic diol (LMD) having 2 to 4 carbon atoms, obtained by alkaline hydrolysis of a polycarbonate diol. The range of alkaline hydrolysis HMD / LMD is preferably 1 / 9 to 9 / 1, more preferably 2 / 8 to 7 / 3, even more preferably 2 / 8 to 6 / 4, and particularly preferably 4 / 6 to 6 / 4.

[0030] (NMR calculation (ce) / (be)) The NMR calculated (ce) / (be) is the molar ratio ((ce) / (be)) of the terminal group represented by formula (ce) to the terminal group represented by formula (be) measured by nuclear magnetic resonance (NMR). The NMR calculated (ce) / (be) is preferably in the range of 9.00 to 0.10, more preferably 2.50 to 0.20, still more preferably 2.0 to 0.20, and particularly preferably 2.0 to 0.5.

[0031] The formula (i-2) satisfies (NMR calculation (ce) / (be))>(alkali hydrolysis HMD / LMD), but more preferably satisfies the following formula (ii-2). (NMR calculation (ce) / (be)) - (HMD / LMD of alkaline hydrolysis) ≥ 0.001 (ii-2)

[0032] In formula (ii-2), "(NMR calculated (ce) / (be)) - (HMD / LMD due to alkaline hydrolysis)" is preferably 0.005 or more, more preferably 0.01 or more, and even more preferably 0.15 or more. The upper limit of "(NMR calculated (ce) / (be)) - (HMD / LMD due to alkaline hydrolysis)" in formula (ii-2) is not particularly limited, but is, for example, 9 or less.

[0033] [Number average molecular weight] The number average molecular weight of the polycarbonate diol of the present embodiment is preferably 300 or more and 10,000 or less, more preferably 400 or more and 5,000 or less, and even more preferably 500 or more and 3,000 or less.

[0034] When the number average molecular weight is equal to or greater than the lower limit, the flexibility and low-temperature properties of the thermoplastic urethane obtained from the polycarbonate diol tend to be better, whereas when the number average molecular weight is equal to or less than the upper limit, the molding processability of the thermoplastic urethane obtained from the polycarbonate diol tends to be better.

[0035] In the present embodiment, the number average molecular weight of the polycarbonate diol can be calculated from the hydroxyl value of the polycarbonate diol using the method described in the examples below.

[0036] Next, the repeating unit represented by formula (A) (also referred to as "polycarbonate structure") will be described in detail below.

[0037] In the polycarbonate structure represented by formula (A), R is a divalent aliphatic or alicyclic hydrocarbon having a carbon number of 2 to 15. Multiple Rs may be the same or different.

[0038] The divalent linear aliphatic hydrocarbon group for R has 2 to 15 carbon atoms, preferably 3 to 12 carbon atoms, and more preferably 4 to 10 carbon atoms.

[0039] Specific examples of the divalent linear aliphatic hydrocarbon group having 2 to 15 carbon atoms represented by R are not particularly limited, and include, for example, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptylene group, and an octylene group. Among these, from the viewpoint of versatility, a trimethylene group, a butylene group, a pentylene group, or a hexylene group is preferred.

[0040] The divalent branched aliphatic hydrocarbon group for R has 3 to 15 carbon atoms, preferably 3 to 12 carbon atoms, and more preferably 3 to 10 carbon atoms.

[0041] Specific examples of the divalent branched aliphatic hydrocarbon group for R include, but are not limited to, an isopropylene group, an isobutylene group, a tert-butylene group, an isopentylene group, a 2,2-dimethyltrimethylene group, an isohexylene group, an isoheptylene group, an isooctylene group, etc. Among these, an isopentylene group or an isohexylene group is preferred from the viewpoint of versatility.

[0042] The divalent alicyclic hydrocarbon group for R has 3 or more and 15 or less carbon atoms, preferably 6 or more and 15 or less carbon atoms, and more preferably 6 or more and 10 or less carbon atoms.

[0043] Specific examples of the divalent cyclic aliphatic hydrocarbon group for R include, but are not limited to, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, etc. Among these, from the viewpoint of versatility, a cyclopentylene group or a cyclohexylene group is preferred.

[0044] Among these, R is preferably a divalent linear aliphatic hydrocarbon group having from 2 to 10 carbon atoms, or a divalent branched aliphatic hydrocarbon group having from 3 to 10 carbon atoms, and more preferably a divalent linear aliphatic hydrocarbon group having from 3 to 10 carbon atoms.

[0045] [Method for producing polycarbonate diol] The polycarbonate diol of the present embodiment can be obtained, for example, by reacting a carbonate compound with a diol compound in the presence of a transesterification catalyst.

[0046] (carbonate compounds) The carbonate compound used in the production of the polycarbonate diol of the present embodiment is not limited to the following, but examples thereof include alkylene carbonate, dialkyl carbonate, diaryl carbonate, etc.

[0047] The alkylene carbonate is not particularly limited, but examples thereof include ethylene carbonate, trimethylene carbonate, 1,2-propylene carbonate, 1,2-butylene carbonate, 1,3-butylene carbonate, and 1,2-pentylene carbonate.

[0048] The dialkyl carbonate is not particularly limited, but examples thereof include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and dibutyl carbonate.

[0049] The diaryl carbonate is not particularly limited, but examples thereof include diphenyl carbonate.

[0050] Among these, the carbonate compound used in the production of polycarbonate diol is preferably alkylene carbonate, and more preferably dimethyl carbonate or ethylene carbonate.

[0051] (Diol compounds) The diol compound used in the production of the polycarbonate diol is not limited to the following, but examples thereof include linear diols, branched diols, cyclic diols, and diols having an aromatic ring.

[0052] The linear diol is not particularly limited, but examples thereof include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nanodiol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol.

[0053] The branched diol is not particularly limited, but examples thereof include 2-methyl-1,8-octanediol, neopentyl glycol, 2-ethyl-1,6-hexanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,4-dimethyl-1,5-pentanediol, and 2,4-diethyl-1,5-pentanediol.

[0054] The cyclic diol is not particularly limited, but examples thereof include 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and 2-bis(4-hydroxycyclohexyl)-propane.

[0055] [Production conditions for polycarbonate diol] When producing the polycarbonate diol of this embodiment, a transesterification catalyst can be used.

[0056] The transesterification catalyst is not particularly limited, but examples thereof include alkali metals and alkaline earth metals, as well as their alcoholates, hydrides, oxides, amides, hydroxides and salts.

[0057] The salts of alkali metals and alkaline earth metals are not particularly limited, but examples thereof include carbonates, nitrogen-containing borates, and basic salts with organic acids.

[0058] The alkali metal is not particularly limited, but examples thereof include lithium, sodium, and potassium.

[0059] The alkaline earth metal is not particularly limited, but examples thereof include magnesium, calcium, strontium, and barium.

[0060] Furthermore, the transesterification catalyst using a metal other than an alkali metal or an alkaline earth metal is not particularly limited, but examples thereof include metals other than alkali metals and alkaline earth metals, as well as salts thereof, alcoholates thereof, and organic compounds containing such metals.

[0061] Specific examples of metals other than alkali metals and alkaline earth metals include, but are not limited to, aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, silver, indium, tin, antimony, tungsten, rhenium, osmium, iridium, platinum, gold, thallium, lead, bismuth, and ytterbium.

[0062] These transesterification catalysts can be used alone or in combination of two or more.

[0063] Among these, the transesterification catalyst is preferably one or more metals selected from the group consisting of sodium, potassium, magnesium, potassium, titanium, zirconium, tin, lead, and ytterbium, or salts thereof, alkoxides thereof, or organic compounds containing these metals, because the transesterification reaction to obtain a polycarbonate diol proceeds more smoothly and the use of the obtained polycarbonate diol has less effect on the urethane reaction.

[0064] The transesterification catalyst is more preferably one or more metals selected from the group consisting of magnesium, titanium, ytterbium, tin, and zirconium.

[0065] Specific examples of preferred transesterification catalysts include organic lead compounds and organic titanium compounds.

[0066] The organic lead compound is not particularly limited, but examples thereof include lead acetate trihydrate, tetraphenyl lead, and lead stearate.

[0067] The organic titanium compound is not particularly limited, but examples thereof include titanium tetra-n-butoxide, titanium tetra-n-propoxide, and titanium tetraisopropoxide.

[0068] The amount of the transesterification catalyst used is preferably 0.00001% by mass or more and 0.1% by mass or less, and more preferably 0.0001% by mass or more and 0.05% by mass or less, based on the total mass of the raw materials.

[0069] When heat treatment is performed following the production of polycarbonate diol, the transesterification catalyst used in the transesterification reaction is not consumed in the transesterification reaction, and therefore the amount can be calculated based on the amount of the transesterification catalyst used. When a commercially available polycarbonate diol is used, the amount of metal in the transesterification catalyst contained in the polycarbonate diol can be determined by measuring it by ICP (Inductively Coupled Plasma) emission spectroscopy.

[0070] The polycarbonate diol of the present embodiment can also be produced by a transesterification reaction between a polycarbonate diol and a diol compound, or between two or more types of polycarbonate diols.

[0071] When the polycarbonate diol raw material contains a catalyst poison or the like of the transesterification catalyst used in its production, the transesterification reaction usually tends to proceed less easily. Therefore, when producing the polycarbonate diol, a necessary amount of the above-mentioned transesterification catalyst can be newly added.

[0072] On the other hand, when the polycarbonate diol raw material does not contain any catalyst poison for the transesterification catalyst, the transesterification reaction in this embodiment usually tends to proceed easily. However, when it is desired to lower the reaction temperature or shorten the reaction time in the production process of the polycarbonate diol, a necessary amount of a new transesterification catalyst can be added. In this case, the same transesterification catalyst as that used in the production of the polycarbonate diol raw material can be used.

[0073] Specifically, the transesterification reaction can be carried out by mixing the raw materials and stirring them while heating.

[0074] The temperature of the transesterification reaction is not particularly limited, but is preferably 120°C or higher and 250°C or lower, more preferably 140°C or higher and 200°C or lower.

[0075] By setting the reaction temperature to the above lower limit or more, the transesterification reaction can be carried out in a shorter time, which is economically advantageous. By setting the reaction temperature to the above upper limit or less, coloration of the resulting polycarbonate diol can be more effectively prevented.

[0076] The reaction pressure of the transesterification reaction is not particularly limited, but is preferably from atmospheric pressure to 1 MPa. By setting the reaction pressure within the above range, the reaction can be carried out more easily. Furthermore, when using auxiliary materials, the transesterification reaction can be promoted more efficiently by applying a certain amount of pressure in consideration of the vapor pressure of these materials.

[0077] The progress and completion of the transesterification reaction can be confirmed by GPC measurement. As the transesterification reaction progresses, the peak derived from the raw material becomes smaller over time, and can be confirmed by the disappearance of the peak.

[0078] In the method for producing polycarbonate diol, a step of dehydrating the raw materials to be used may be carried out as a pretreatment before the above-mentioned transesterification reaction.

[0079] In the method for producing polycarbonate diol, after the above-mentioned transesterification reaction, a step of adding the above-mentioned catalyst poison to the transesterification catalyst may be carried out as a post-treatment.

[0080] (Method for producing polycarbonate diol of the first embodiment) The method for producing a polycarbonate diol of the present embodiment includes a step of adjusting the terminal structure of the polycarbonate diol.

[0081] When producing the polycarbonate diol of the first embodiment, this step may be either step (X) of decreasing the terminal groups represented by formula (BE) or step (Y) of increasing the terminal groups represented by formula (CE). Specific adjustment methods include the following methods, which may be used alone or in combination of two or more. This allows the preparation of a polycarbonate diol that satisfies formula (i).

[0082] Step (X): A method of reducing the number of terminal groups represented by formula (BE) by preferentially extracting 1,4-butanediol from the terminals of the carbonate diol by subjecting the obtained polycarbonate diol to condensation polymerization at 180°C or higher and 250°C or lower under reduced pressure.

[0083] Step (Y): A method of increasing the number of terminal groups represented by formula (CE) by transesterifying the obtained polycarbonate diol with 1,6-hexanediol or a polycarbonate diol prepared using 1,6-hexanediol alone.

[0084] In addition to the steps (X) and (Y), a polycarbonate diol satisfying the formula (i) can also be prepared by appropriately adjusting the type of raw material, reaction temperature, reaction pressure and reaction time.

[0085] The ratio of the terminal groups represented by formula (BE) and formula (CE) to the total amount of terminal groups is 1 It can be calculated by H-NMR. More specifically, it can be measured by the method described in the Examples below.

[0086] (Method for producing polycarbonate diol according to the second embodiment) The method for producing a polycarbonate diol of the present embodiment includes a step of adjusting the terminal structure of the polycarbonate diol.

[0087] When producing the polycarbonate diol of the second embodiment, this step may be either step (x) of decreasing the terminal groups represented by formula (be) or step (y) of increasing the terminal groups represented by formula (ce). Specific adjustment methods include the following methods, which may be used alone or in combination of two or more. This allows the preparation of a polycarbonate diol that satisfies formula (i-2).

[0088] Step (x): A method of reducing the number of end groups represented by formula (be) by preferentially extracting a divalent aliphatic or alicyclic diol having 2 to 4 carbon atoms (hereinafter also referred to as "LMD") from the terminal of the carbonate diol by condensation polymerizing the obtained polycarbonate diol under reduced pressure at 180°C or higher and 250°C or lower. The method of preferentially extracting LMD from the terminal of the carbonate diol is not particularly limited, but examples include a method of carrying out a polymerization reaction at a temperature 80°C or higher than the boiling point of LMD under reduced pressure.

[0089] Step (y): A method of increasing the number of terminal groups represented by formula (ce) by transesterifying the obtained polycarbonate diol with a divalent aliphatic or alicyclic diol (HMD) having 5 to 15 carbon atoms, or a polycarbonate diol prepared by homopolymerizing or copolymerizing a divalent aliphatic or alicyclic diol (HMD) having 5 to 15 carbon atoms.

[0090] In addition to the steps (x) and (y), a polycarbonate diol satisfying the formula (i-2) can also be prepared by appropriately adjusting the type of raw material, reaction temperature, reaction pressure and reaction time.

[0091] The ratio of the terminal groups represented by formula (be) and formula (ce) to the total amount of terminal groups is 1 It can be calculated by H-NMR. More specifically, it can be measured by the method described in the Examples below.

[0092] [Storage method for polycarbonate diol] The storage method of this embodiment is a method for storing the above-mentioned polycarbonate diol, in which the polycarbonate is stored in a state where it has fluidity. Storing the polycarbonate in a state where it has fluidity results in excellent handleability of the polycarbonate. The method of "storing the polycarbonate in a state where it has fluidity" is not particularly limited, but examples include storing the polycarbonate by heating it to or maintaining it at a temperature where the polycarbonate becomes fluid. The heating or storage temperature of the polycarbonate is preferably 50°C or higher, more preferably 55°C or higher, and even more preferably 60°C or higher. The upper limit of the temperature is not particularly limited, but from the viewpoint of suppressing decomposition of the polycarbonate diol, it is preferably 180°C or lower, more preferably 150°C or lower, and even more preferably 120°C or lower. [Example]

[0093] The present embodiment will be described in more detail below with reference to specific examples and comparative examples, but the present embodiment is not limited to these examples and comparative examples as long as it does not deviate from the gist of the present invention. The evaluations and physical properties in the examples and comparative examples described below were evaluated and measured by the following methods. In the examples, "parts" and "%" are based on mass unless otherwise specified.

[0094] (Measurement of number average molecular weight) The number average molecular weight was determined from the hydroxyl value as described below.

[0095] (Measurement of hydroxyl value) The hydroxyl value was measured by the following method. An acetylation reagent was prepared by adding pyridine to 12.5 g of acetic anhydride in a volumetric flask to make a 50 mL solution. 2.5 to 5.0 g of sample was precisely weighed and placed in a 100 mL recovery flask. 5 mL of acetylation reagent and 10 mL of toluene were added to the recovery flask using a volumetric pipette, and then a condenser was attached and the mixture was heated and stirred at 100°C for 1 hour. 2.5 mL of distilled water was added to the recovery flask using a volumetric pipette and heated and stirred for an additional 10 minutes. After cooling for 2 to 3 minutes, 12.5 mL of ethanol was added to the recovery flask. After adding 2 to 3 drops of phenolphthalein as an indicator, the mixture was titrated with 0.5 mol / L ethanolic potassium hydroxide. 5 mL of acetylation reagent, 10 mL of toluene, and 2.5 mL of distilled water were placed in a 100 mL recovery flask and heated and stirred for 10 minutes. Titration was then performed in the same manner (blank test). Based on these results, the hydroxyl value was calculated using the following formula (I): Hydroxyl value (mg-KOH / g) = {(ba) × 28.05 × f} / e (I) a represents the titer (mL) of the sample, b represents the titer (mL) of the blank, e represents the sample volume (g), and f represents the titrant factor. The number average molecular weight of the polycarbonate diol was calculated using the following formula (II). Number average molecular weight = 2 / (OH value × 10 -3 / 56.11)···(II) The OH value represents the hydroxyl value (mg-KOH / g).

[0096] (Alkaline hydrolyzed HDL / BDL) Alkaline hydrolysis HDL / BDL was determined as follows. One gram of sample was placed in a 100 mL recovery flask, and 30 g of ethanol and 4 g of potassium hydroxide were added. The mixture was then incubated at 100°C for 1 hour. After cooling to room temperature, 2–3 drops of phenolphthalein were added as an indicator and neutralized with hydrochloric acid. The recovery flask was then cooled in a refrigerator for 1 hour, after which the precipitated salt was removed by filtration and analyzed by gas chromatography. The concentration of each dihydroxy compound was calculated by calculating the weight percentage from the area ratio obtained by gas chromatography (GC) using a calibration curve prepared in advance using known dihydroxy compounds as standard substances. The analysis was performed using a gas chromatograph GC-14B (Shimadzu Corporation) equipped with a DB-WAX (J&W) column and a flame ionization detector (FID). The column temperature profile was as follows: 60°C for 5 minutes, followed by a 10°C / min increase to 250°C. The molar ratio of 1,6-hexanediol to 1,4-butanediol was calculated from the obtained area value to determine the alkaline hydrolyzed HDL / BDL. For example, when the diols obtained as a result of alkaline hydrolysis are 1,6-hexanediol (52 mol %) and 1,4-butanediol (48 mol %), the alkaline hydrolysis HDL / BDL is 52 / 48=1.08.

[0097] (NMR calculation (CE) / (BE)) In the polycarbonate diol of this embodiment, the molar ratio (CE) / (BE) of the terminal group represented by formula (CE) to the terminal group represented by formula (BE) was measured by nuclear magnetic resonance (NMR) as follows. 1 H-NMR device: ECS400 (manufactured by JEOL RESONANCE) Observation nucleus (frequency): 1H (400MHz) Solvent: CDCl3 Concentration: 5wt / vol% Shift standard: TMS (0.00 ppm) Number of times accumulated: 256 In the above measurement, the integral values ​​of the following signals were divided by the number of hydrogen atoms, and the molar ratios were calculated from the values ​​obtained. The specific calculation method is as follows: Amount of terminal groups represented by formula (BE): The integral value of the vicinity of 3.65 to 3.70 ppm (peak bb in formula B-1 below) divided by 2 Amount of terminal groups represented by formula (CE): integral value of around 3.60 to 3.65 ppm (peak cc in formula C-1 below) divided by 2 [ka] (A in formula (B-1) means formula (A).) [ka] (A in formula (C-1) means formula (A).) For example, if the NMR measurement results show that the amount of terminal groups represented by formula (BE) is 1.00 and the amount of terminal groups represented by formula (CE) is 0.87, the NMR calculation (CE) / (BE) is 0.87÷1.00=0.87.

[0098] (Alkaline hydrolysis HMD / LMD) Gas chromatography analysis was performed under the same conditions as for the measurement of alkaline hydrolyzed HDL / BDL described above to obtain peak area values ​​for HMD and LMD. The molar ratio of HMD to LMD was calculated from the obtained area values ​​to determine alkaline hydrolyzed HMD / LMD.

[0099] (NMR calculation (ce) / (be)) NMR measurements were carried out under the same conditions as in the measurement of the NMR calculation (CE) / (BE) described above. The integral value of the peak derived from the hydrogen bonded to the carbon adjacent to the terminal OH group was read from the obtained NMR chart, and the amount of the terminal group represented by formula (ce) and the amount of the terminal group represented by formula (be) was calculated by dividing the amount of the terminal group represented by formula (ce) by the amount of the terminal group represented by formula (be). The NMR calculated value (ce) / (be) was calculated by dividing the amount of the terminal group represented by formula (ce) by the amount of the terminal group represented by formula (be).

[0100] (High temperature storage stability) Using the polycarbonate diols obtained in the Examples and Comparative Examples as samples, the reaction rates of the polycarbonate diols before the high-temperature storage stability test were determined as shown below (measurement of reaction rate). Furthermore, the reaction rates of the samples were measured again after storing them at 60°C for 1 to 5 months. The absolute value of the change in reaction rate was evaluated as follows: less than 1.0%: ◎; 1.0% or more but less than 2.0%: ○; 2.0% or more but less than 3.0%: △; and 3.0% or more: ×. For example, if the reaction rate before the test is 35.2% and the reaction rate after storage at 60°C for one month is 35.4%, the absolute value of the change in reaction rate is |35.4-35.2|÷35.2=0.57%.

[0101] (Measurement of reaction rate) [Preparation of amine solution] A 0.2N dibutylamine solution was prepared using 25.85 g of dibutylamine and 865 g of toluene. Next, 10 mL of the 0.2N dibutylamine solution was added to 10 g of dimethylformamide (DMF) and stirred until homogenous, thereby preparing an amine solution. [Blank titration] The above amine solution was titrated with 0.1 mol / L 2-propanol hydrochloric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) using bromocresol green as an indicator. [Reaction rate evaluation] 20 g of sample and toluene were added to a 200 mL four-necked recovery flask to a solids content of 30%, and the mixture was heated and stirred at 80°C with a condenser attached. Next, 4,4-diphenylmethane diisocyanate, which had been preheated to 80°C, was added to the recovery flask to achieve an NCO / OH ratio of 2.00, to initiate the reaction. Approximately 5 mL of the reaction solution was sampled 40 minutes after the start of the reaction and quickly poured into the amine solution, followed by stirring for 3 minutes. The reaction solution was then titrated with 0.1 mol / L 2-propanol hydrochloric acid (Fujifilm Wako Pure Chemical Industries, Ltd.) using bromocresol green as an indicator. Based on these results, the OH reaction rate, calculated using the following formula, was calculated as the reaction rate: Residual NCO (mol / g) = (HJ) / 1000 × 0.1 × F × / W H: Blank titration volume (mL) J: Titration volume of reaction solution (mL) W: Sampling amount (g) F: Factor of titrant OH reaction rate (%) = ((N1-Ns) / O1) × 100 N1: NCO groups of the charged 4,4-diphenylmethane diisocyanate (mol / g) Ns: Residual NCO (mol / g) calculated by the above formula O1: Hydroxyl value of the polycarbonate diol

[0102] [Example 1] A 1-L glass flask (reactor) equipped with a rectification column filled with structured packing and a stirrer was charged with 245 g of 1,4-butanediol, 240 g of 1,6-hexanediol, and 420 g of ethylene carbonate, followed by 0.11 g of titanium tetra-n-butoxide as a catalyst. The reactor was immersed in a 165°C oil bath, and the reaction was carried out for 18 hours at a reaction temperature of 140-150°C while a portion of the distillate was withdrawn. The reactor was then directly connected to a condenser, the reaction temperature was increased to 185°C, and the pressure was gradually reduced to 0.6 kPa, and the reaction was carried out for an additional 5 hours. Next, dibutyl phosphate was added in an amount 2.0 times the molar ratio of titanium tetra-n-butoxide, and the mixture was heated at 115°C for 3 hours to obtain polycarbonate diol PC-1 (431 g), which is liquid at room temperature. The obtained polycarbonate diol PC-1 had a hydroxyl value of 53.6 mg KOH / g and a number average molecular weight of 2094. In addition, in the obtained PC-1, the amount of repeating units represented by formula (B) was 48.9 mol% and the amount of repeating units represented by formula (C) was 51.1 mol% relative to the total amount of repeating units represented by formula (A). In addition, in the obtained PC-1, the amount of terminal groups represented by formula (BE) was 47.6 mol% and the amount of terminal groups represented by formula (CE) was 52.4 mol% relative to the total amount of terminal groups. The obtained PC-1 was evaluated according to the above-mentioned method, and the evaluation results are shown in Table 1.

[0103] [Comparative Example 1] A 1-L glass flask (reactor) equipped with a rectification column filled with structured packing and a stirrer was charged with 245 g of 1,4-butanediol, 240 g of 1,6-hexanediol, and 420 g of ethylene carbonate, followed by 0.13 g of titanium tetra-n-butoxide as a catalyst. The reactor was immersed in a 165°C oil bath, and the reaction was carried out at a reaction temperature of 140-150°C for 18 hours while a portion of the distillate was withdrawn. The reactor was then directly connected to a condenser, the reaction temperature was raised to 170°C, and the pressure was gradually reduced to 1.0 kPa, and the reaction was carried out for an additional 10 hours. Next, dibutyl phosphate was added in an amount 2.0 times the molar ratio of titanium tetra-n-butoxide, and the mixture was heated at 115°C for 3 hours to obtain polycarbonate diol PC-2 (422 g), which is liquid at room temperature. The hydroxyl value of the obtained polycarbonate diol PC-2 was 54.3 mg KOH / g. The number average molecular weight was 2067. In the obtained PC-2, the amount of repeating units represented by formula (B) was 49.3 mol% and the amount of repeating units represented by formula (C) was 50.7 mol% relative to the total amount of repeating units represented by formula (A). In the obtained PC-2, the amount of terminal groups represented by formula (BE) was 53.8 mol% and the amount of terminal groups represented by formula (CE) was 46.2 mol% relative to the total amount of terminal groups. The obtained PC-2 was evaluated according to the above-mentioned method, and the evaluation results are shown in Table 1.

[0104] [Example 2] A 3.0 L glass flask (reactor) equipped with a stirrer was charged with 1,487 g of Duranol T4692 (manufactured by Asahi Kasei Corporation; a copolymer polycarbonate diol using 1,4-butanediol and 1,6-hexanediol as diols and having a number average molecular weight of approximately 2,000; diol composition ratio: 1,4-butanediol / 1,6-hexanediol = 90 mol% / 10 mol%) and 513 g of Duranol T6002 (manufactured by Asahi Kasei Corporation; a polycarbonate diol using 1,6-hexanediol as the diol and having a number average molecular weight of approximately 2,000). Then, 0.13 g of titanium tetra-n-butoxide was added as a catalyst. The contents were then heated with stirring, and the temperature inside the reactor was maintained at approximately 145°C for 3 hours. Next, dibutyl phosphate was added in an amount 2.0 times the molar ratio of titanium tetra-n-butoxide, and the mixture was heated at a reactor temperature of 115°C for 3 hours to obtain polycarbonate diol PC-3. Regarding the transesterification reaction, the reaction solution was subjected to GPC measurement over time to confirm the disappearance of peaks derived from the raw materials and the appearance of peaks derived from the product over time, thereby confirming the progress of the reaction. The obtained polycarbonate diol PC-3 had a hydroxyl value of 55.7 mg KOH / g and a number average molecular weight of 2015. In addition, in the obtained PC-3, the amount of repeating units represented by formula (B) was 68.0 mol% and the amount of repeating units represented by formula (C) was 32.0 mol% relative to the total amount of repeating units represented by formula (A). In addition, in the obtained PC-3, the amount of terminal groups represented by formula (BE) was 63.2 mol% and the amount of terminal groups represented by formula (CE) was 36.8 mol% relative to the total amount of terminal groups. The obtained PC-3 was evaluated according to the above-mentioned method, and the evaluation results are shown in Table 1.

[0105] Comparative Example 2 A 1-L glass flask (reactor) equipped with a rectification column filled with structured packing and a stirrer was charged with 330 g of 1,4-butanediol, 142 g of 1,6-hexanediol, and 430 g of ethylene carbonate, followed by 0.13 g of titanium tetra-n-butoxide as a catalyst. The reactor was immersed in a 165°C oil bath, and the reaction was carried out at a reaction temperature of 140-150°C for 18 hours while a portion of the distillate was withdrawn. The reactor was then directly connected to a condenser, the reaction temperature was raised to 170°C, and the pressure was gradually reduced to 1.0 kPa, and the reaction was carried out for an additional 10 hours. Next, dibutyl phosphate was added in an amount 2.0 times the molar ratio of titanium tetra-n-butoxide, and the mixture was heated at 115°C for 3 hours to obtain polycarbonate diol PC-4 (412 g), which is liquid at room temperature. The obtained polycarbonate diol PC-4 had a hydroxyl value of 55.8 mg KOH / g and a number average molecular weight of 2011. In addition, in the obtained PC-4, the amount of repeating units represented by formula (B) was 68.2 mol% and the amount of repeating units represented by formula (C) was 31.8 mol% relative to the total amount of repeating units represented by formula (A). In addition, in the obtained PC-4, the amount of terminal groups represented by formula (BE) was 71.4 mol% and the amount of terminal groups represented by formula (CE) was 28.6 mol% relative to the total amount of terminal groups. The obtained PC-4 was evaluated according to the above-mentioned methods. The evaluation results are shown in Table 1.

[0106] [Example 3] A 1.0 L glass flask (reactor) equipped with a stirrer was charged with 358 g of Duranol T4692 (manufactured by Asahi Kasei Corporation; a copolymer polycarbonate diol using 1,4-butanediol and 1,6-hexanediol as diols and having a number average molecular weight of approximately 2000; diol composition ratio: 1,4-butanediol / 1,6-hexanediol = 90 mol% / 10 mol%) and 542 g of Duranol T6002 (manufactured by Asahi Kasei Corporation; a polycarbonate diol using 1,6-hexanediol as the diol and having a number average molecular weight of approximately 2000). Then, 0.10 g of titanium tetra-n-butoxide was added as a catalyst. The contents were then heated with stirring, and the temperature inside the reactor was maintained at approximately 145°C for 3 hours. Next, dibutyl phosphate was added in an amount 2.0 times the molar ratio of titanium tetra-n-butoxide, and the mixture was heated at a reactor temperature of 115°C for 3 hours to obtain polycarbonate diol PC-5. Regarding the transesterification reaction, the reaction solution was subjected to GPC measurement over time to confirm the disappearance of peaks derived from the raw materials and the appearance of peaks derived from the product over time, thereby confirming the progress of the reaction. The obtained polycarbonate diol PC-5 had a hydroxyl value of 55.9 mg KOH / g and a number average molecular weight of 2007. In addition, in the obtained PC-5, the amount of repeating units represented by formula (B) was 39.8 mol% and the amount of repeating units represented by formula (C) was 60.2 mol% relative to the total amount of repeating units represented by formula (A). In addition, in the obtained PC-5, the amount of terminal groups represented by formula (BE) was 37.7 mol% and the amount of terminal groups represented by formula (CE) was 62.3 mol% relative to the total amount of terminal groups. The obtained PC-5 was evaluated according to the above-mentioned methods. The evaluation results are shown in Table 1.

[0107] [Example 4] A 1.0 L glass flask (reactor) equipped with a stirrer was charged with 561 g of Duranol T4692 (manufactured by Asahi Kasei Corporation; a copolymer polycarbonate diol using 1,4-butanediol and 1,6-hexanediol as diols and having a number average molecular weight of approximately 2000; diol composition ratio: 1,4-butanediol / 1,6-hexanediol = 90 mol% / 10 mol%) and 339 g of Duranol T6002 (manufactured by Asahi Kasei Corporation; a polycarbonate diol using 1,6-hexanediol as the diol and having a number average molecular weight of approximately 2000). Then, 0.11 g of titanium tetra-n-butoxide was added as a catalyst. The contents were then heated with stirring, and the temperature inside the reactor was maintained at approximately 145°C for 3 hours. Next, dibutyl phosphate was added in an amount 2.0 times the molar ratio of titanium tetra-n-butoxide, and the mixture was heated at a reactor temperature of 115°C for 3 hours to obtain polycarbonate diol PC-6. Regarding the transesterification reaction, the reaction solution was subjected to GPC measurement over time to confirm the disappearance of peaks derived from the raw materials and the appearance of peaks derived from the product over time, thereby confirming the progress of the reaction. The obtained polycarbonate diol PC-6 had a hydroxyl value of 55.5 mgKOH / g and a number average molecular weight of 2022. In the obtained PC-6, the amount of repeating units represented by formula (B) was 60.0 mol% and the amount of repeating units represented by formula (C) was 40.0 mol% relative to the total amount of repeating units represented by formula (A). In the obtained PC-6, the amount of terminal groups represented by formula (BE) was 55.0 mol% and the amount of terminal groups represented by formula (CE) was 45.0 mol% relative to the total amount of terminal groups. The obtained PC-6 was evaluated according to the above-mentioned methods. The evaluation results are shown in Table 1.

[0108] [Example 5] A 1-L glass flask (reactor) equipped with a rectification column filled with structured packing and a stirrer was charged with 200 g of 1,3-propanediol, 230 g of 1,10-decanediol, and 380 g of ethylene carbonate, followed by 0.18 g of titanium tetra-n-butoxide as a catalyst. The reactor was immersed in a 165°C oil bath, and the reaction was carried out for 18 hours at a reaction temperature of 140-150°C while a portion of the distillate was withdrawn. The reactor was then directly connected to a condenser, the reaction temperature was increased to 185°C, and the pressure was gradually reduced to 0.6 kPa, and the reaction was carried out for an additional 5 hours. Next, dibutyl phosphate was added in an amount 2.0 times the molar ratio of titanium tetra-n-butoxide, and the mixture was heated at 115°C for 3 hours to obtain polycarbonate diol PC-7 (388 g), which is liquid at room temperature. The obtained polycarbonate diol PC-7 had a hydroxyl value of 54.8 mg KOH / g and a number average molecular weight of 2048. In addition, in the obtained PC-7, the amount of repeating units represented by formula (b) was 45.7 mol% and the amount of repeating units represented by formula (c) was 54.3 mol% relative to the total amount of repeating units represented by formula (A). In addition, in the obtained PC-7, the amount of terminal groups represented by formula (be) was 43.3 mol% and the amount of terminal groups represented by formula (ce) was 56.7 mol% relative to the total amount of terminal groups. The obtained PC-7 was evaluated according to the above-mentioned methods. The evaluation results are shown in Table 1.

[0109] Comparative Example 3 A 3-L glass flask (reactor) equipped with a rectification column packed with structured packing and a stirrer was charged with 550 g of 1,4-butanediol, 650 g of 1,6-hexanediol, and 970 g of ethylene carbonate, followed by the addition of 0.10 g of titanium tetra-n-butoxide as a catalyst. The reaction temperature was adjusted to 150°C under a reduced pressure of 20 torr (approximately 2.67 kPa), and the reaction was carried out for 20 hours while withdrawing a portion of the distillate. The reactor was then directly connected to a condenser, the reaction temperature was increased to 190°C, and the pressure was gradually reduced to 7 torr (approximately 0.93 kPa), and the reaction was carried out for an additional 4 hours. Next, dibutyl phosphate was added in an amount 2.0 times the molar ratio of titanium tetra-n-butoxide, and the mixture was heated at 115°C for 3 hours to obtain polycarbonate diol PC-8 (684 g), which is liquid at room temperature. The obtained polycarbonate diol PC-8 had a hydroxyl value of 55.4 mg KOH / g and a number average molecular weight of 2025. In addition, in the obtained PC-8, the amount of repeating units represented by formula (B) was 46.6 mol% and the amount of repeating units represented by formula (C) was 53.4 mol% relative to the total amount of repeating units represented by formula (A). In addition, in the obtained PC-8, the amount of terminal groups represented by formula (BE) was 47.9 mol% and the amount of terminal groups represented by formula (CE) was 52.1 mol% relative to the total amount of terminal groups. The obtained PC-8 was evaluated according to the above-mentioned methods. The evaluation results are shown in Table 1.

[0110] [Table 1]

[0111] From the above, it was confirmed that the polycarbonate diol of this example has excellent high-temperature storage stability. [Industrial Applicability]

[0112] The polycarbonate diol of the present invention can be suitably used in a wide range of fields, such as automobiles, buses, railway vehicles, construction machinery, agricultural machinery, floors, walls and roofs of buildings, metal products, mortar and concrete products, woodworking products, plastic products, and coating materials for ceramic building materials such as calcium silicate boards and gypsum boards.

Claims

1. A polycarbonate diol containing a repeating unit represented by the following formula (A) and having a terminal hydroxyl group: 90 to 100 mol % of the repeating units of formula (A) are repeating units represented by the following formulas (B) and (C): the amount of the repeating unit represented by formula (B) is 10 to 90 mol % based on the total amount of the repeating unit represented by formula (A); 90 mol % or more of the total amount of terminal groups are terminal groups represented by the following formula (B-E) and / or (C-E), A polycarbonate diol that satisfies the following formula (i): 【Chemistry 1】 (In formula (A), R represents a divalent aliphatic hydrocarbon having 2 to 15 carbon atoms or a divalent alicyclic hydrocarbon having 3 to 15 carbon atoms.) 【Chemistry 2】 【Transformation 3】 【Chemistry 4】 (In formula (B-E), A means formula (A).) 【Transformation 5】 (In formula (C-E), A represents formula (A).) (NMR calculation (C−E) / (B−E))>(alkali hydrolyzed HDL / BDL) (i) (In formula (i), NMR calculated (C-E) / (B-E) is the molar ratio of the end group represented by formula (C-E) to the end group represented by formula (B-E) measured by nuclear magnetic resonance (NMR), and alkaline hydrolyzed HDL / BDL is the molar ratio of 1,6-hexanediol (HDL) to 1,4-butanediol (BDL) obtained by alkaline hydrolysis of polycarbonate diol, and is calculated based on the measurement method described below.) (Method for measuring alkaline hydrolyzed HDL / BDL) 1 g of the sample is placed in a 100 mL recovery flask, and then 30 g of ethanol and 4 g of potassium hydroxide are added, followed by reaction at 100°C for 1 hour. After cooling to room temperature, 2-3 drops of phenolphthalein were added to the recovery flask as an indicator and the mixture was neutralized with hydrochloric acid. The recovery flask was then cooled in a refrigerator for 1 hour, after which the precipitated salt was removed by filtration and analyzed by gas chromatography. The concentration of each dihydroxy compound was determined by preparing a calibration curve using known dihydroxy compounds as standard substances, and calculating the weight percentage from the area ratio obtained by gas chromatography (GC). The analysis was performed using a gas chromatograph GC-14B (Shimadzu Corporation) equipped with a DB-WAX (J&W) column and a flame ionization detector (FID). The column temperature profile was as follows: 60°C for 5 minutes, followed by a 10°C / min increase to 250°C. The molar ratio of 1,6-hexanediol to 1,4-butanediol was calculated from the obtained area values ​​to determine the alkaline hydrolysis HDL / BDL.

2. The polycarbonate diol according to claim 1, wherein the amount of the repeating unit represented by formula (B) is 30 to 80 mol % based on the total amount of the repeating unit represented by formula (A).

3. The polycarbonate diol according to claim 1, wherein the amount of the repeating unit represented by formula (B) is 30 to 70 mol % based on the total amount of the repeating unit represented by formula (A).

4. The polycarbonate diol according to claim 1, wherein the amount of the repeating unit represented by formula (B) is 40 to 60 mol % based on the total amount of the repeating unit represented by formula (A).

5. A polycarbonate diol containing a repeating unit represented by the following formula (A) and having a terminal hydroxyl group: The repeating units of formula (A) are repeating units represented by the following formulas (b) and (c): the amount of the repeating unit represented by formula (b) is 10 to 60 mol % based on the total amount of the repeating unit represented by formula (A); 90 mol % or more of the total amount of terminal groups are terminal groups represented by the following formula (be) and / or (ce), A polycarbonate diol satisfying the following formula (i-2) (excluding those containing a repeating unit represented by the following formula (A')). 【Transformation 6】 (In formula (A), R represents a divalent aliphatic hydrocarbon having 2 to 15 carbon atoms or a divalent alicyclic hydrocarbon having 3 to 15 carbon atoms.) 【Transformation 7】 (In formula (b), R 1 represents a divalent aliphatic hydrocarbon having 2 to 4 carbon atoms. 【Transformation 8】 (In formula (c), R 2 represents a divalent aliphatic hydrocarbon having 5 to 15 carbon atoms or a divalent alicyclic hydrocarbon having 5 to 15 carbon atoms. 【Chemistry 9】 (In formula (b-e), A represents formula (A), and R 11 represents a divalent aliphatic hydrocarbon having 2 to 4 carbon atoms. 【Chemistry 10】 (In formula (ce), A represents formula (A), and R 22 represents a divalent aliphatic hydrocarbon having 5 to 15 carbon atoms or a divalent alicyclic hydrocarbon having 5 to 15 carbon atoms. (NMR calculation (ce) / (be))>(alkali hydrolyzed HMD / LMD) (i-2) (In formula (i-2), NMR calculated (c-e) / (b-e) is the molar ratio of the terminal group represented by formula (c-e) to the terminal group represented by formula (b-e) measured by nuclear magnetic resonance (NMR), and alkaline hydrolyzed HMD / LMD is the molar ratio of the aliphatic diol having 5 to 15 carbon atoms or the alicyclic diol having 5 to 15 carbon atoms (HMD) to the aliphatic diol having 2 to 4 carbon atoms (LMD), which are obtained by alkaline hydrolysis of polycarbonate diol, and is calculated based on the measurement method described below.) (Method for measuring alkaline hydrolysis HMD / LMD) 1 g of the sample is placed in a 100 mL recovery flask, and 30 g of ethanol and 4 g of potassium hydroxide are added, followed by reaction at 100°C for 1 hour. After cooling to room temperature, 2-3 drops of phenolphthalein were added to the recovery flask as an indicator and the mixture was neutralized with hydrochloric acid. The recovery flask was then cooled in a refrigerator for 1 hour, after which the precipitated salt was removed by filtration and analyzed by gas chromatography. The concentration of each dihydroxy compound was determined by preparing a calibration curve using known dihydroxy compounds as standard substances, and calculating the weight percentage from the area ratio obtained by gas chromatography (GC). The analysis was performed using a gas chromatograph GC-14B (Shimadzu Corporation) equipped with a DB-WAX (J&W) column and a flame ionization detector (FID). The column temperature profile was maintained at 60°C for 5 minutes, followed by a 10°C / min increase to 250°C. The molar ratio of HMD to LMD was calculated from the obtained area values ​​to determine the alkaline hydrolysis HMD / LMD. 【Chemistry 11】 (In formula (A'), n is 0 or 1, R 1 and R 2 are each independently a group selected from the group consisting of an alkyl group, aryl group, alkenyl group, alkynyl group, and alkoxy group having 1 to 15 carbon atoms, and may have an oxygen atom, sulfur atom, nitrogen atom, or halogen atom, or a substituent containing any of these, within the carbon number range. X each independently represents a divalent group having 1 to 15 carbon atoms which may contain a heteroatom.

6. The polycarbonate diol according to claim 5, wherein the amount of the repeating unit represented by formula (b) is 30 to 60 mol % based on the total amount of the repeating unit represented by formula (A).

7. The polycarbonate diol according to claim 5, wherein the amount of the repeating unit represented by formula (b) is 40 to 60 mol % based on the total amount of the repeating unit represented by formula (A).

8. R in formula (c) 2 is a divalent aliphatic hydrocarbon group having 6 to 10 carbon atoms, and R in formula (ce) 22 The polycarbonate diol according to any one of claims 5 to 7, wherein is a divalent aliphatic hydrocarbon group having 6 to 10 carbon atoms.

9. A method for storing the polycarbonate diol according to any one of claims 1 to 8, wherein the polycarbonate diol is stored in a fluid state.

10. The storage method according to claim 9, comprising a step of heating or maintaining the temperature of the polycarbonate diol at 50°C or higher during storage.

11. A polyurethane obtained by using the polycarbonate diol according to any one of claims 1 to 8.

12. A coating material comprising the polycarbonate diol according to any one of claims 1 to 8.

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