Polycarbonate diol composition

Abstract

To provide a polycarbonate diol composition that has excellent stability of quality, is less colored, and has excellent compatibility with other polyols, solvents and the like.SOLUTION: A polycarbonate diol composition comprises a repeating structural unit represented by the general formula (I) in the figure, and at least one further repeating structural unit selected from the group consisting of repeating structural units represented by the general formulas (II) to (IV) in the figure, and satisfies specific conditions.SELECTED DRAWING: None

Description

[Technical field]

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

[0002] Conventionally, polyurethane resins have been used in a wide range of applications, such as synthetic leather, artificial leather, adhesives, furniture paints, and automotive paints. Among the raw materials for polyurethane resins, polyethers, polyesters, and polycarbonates are used as polyol components to be reacted with isocyanates. However, in recent years, there has been an increasing demand for polyurethane resins with improved resistance, such as heat resistance, weather resistance, hydrolysis resistance, solvent resistance, sunscreen resistance, and scratch resistance.

[0003] According to Non-Patent Document 1, polyether polyols as polyol components generally have low viscosity. Therefore, polyurethanes using polyether polyols are said to have excellent flexibility and hydrolysis resistance, but poor heat resistance and weather resistance. Polyurethanes using polyester polyols have improved heat resistance and weather resistance, but poor hydrolysis resistance. In contrast, polyurethanes using polycarbonate polyols are said to have the best durability grade in terms of durability such as heat resistance, chemical resistance, and hydrolysis resistance, but have high viscosity and room for improvement in handling.

[0004] In order to solve the above problems, various proposals have been made to introduce ether bonds or ester bonds into polycarbonate polyols. For example, Patent Document 1 describes a production method for synthesizing a copolymerized polycarbonate diol by subjecting a polycarbonate diol to an ester exchange reaction, and Patent Document 2 describes a polyester polyol having a specific structure. Patent Document 3 discloses a coating composition that uses a specific polycarbonate diol composition. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 3-252420 [Patent Document 2] JP 2019-151813 A [Patent Document 3] International Publication No. 2019 / 131617 [Non-patent literature]

[0006] [Non-Patent Document 1] "Polyurethane Material Selection, Structure Control and Modification Case Studies" Items 51 to 62, Published by the Technical Information Association, December 2014, 1st Edition Summary of the Invention [Problem to be solved by the invention]

[0007] However, the techniques described in Patent Documents 1 and 2 leave room for improvement in the color tone of the copolymerized polycarbonate diol, and also leave problems in compatibility with other polyols and solvents. In addition, in the technique described in Patent Document 3, in the method for producing a polycarbonate diol composition, the progress and completion of the reaction are confirmed by GPC measurement, but there is still room for further improvement in the stability of quality.

[0008] Therefore, the present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a polycarbonate diol composition having excellent quality stability, little coloration, and excellent compatibility with other polyols, solvents, etc. [Means for solving the problem]

[0009] As a result of intensive research, the present inventors have found that a polycarbonate diol composition having a specific structure can solve the above problems by satisfying specific conditions, and have arrived at the present invention.

[0010] That is, the present invention relates to the following. [1] A polycarbonate diol composition comprising a repeating structural unit represented by the following general formula (I), and further comprising at least one repeating structural unit selected from the group consisting of a repeating structural unit represented by the following general formula (II), a repeating structural unit represented by the following general formula (III), and a repeating structural unit represented by the following general formula (IV), and satisfying the following formula (Formula 1): [ka] (I) (In general formula (I), R 11 is a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 15 carbon atoms, or an aromatic hydrocarbon group, which may have a heteroatom. 11 may be the same or different.) [ka] (II) (In general formula (II), R 21 is a divalent linear, branched or cyclic aliphatic hydrocarbon group having 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 21 may be the same or different. n21 is any integer.) [ka] (III) (In general formula (III), R 31 is a divalent linear, branched or cyclic aliphatic hydrocarbon group having 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 31 may be the same or different.) [ka] (IV) (In general formula (IV), R 41 and R 42are each independently a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 41 and R 42 may be the same or different.) xy≧3.7×α (α=22.4×Mn -0.41 )...(Formula 1) (In formula 1, x is the ratio of the content (mass%) of the repeating structural unit represented by the general formula (I) to the total mass (mass%) of the repeating structural units represented by the general formulas (I) to (IV), y is the titration amount (mL) of the polycarbonate diol composition by the cloud point titration method, and Mn is the number average molecular weight of the polycarbonate diol composition.) [2] A polycarbonate diol composition comprising a repeating structural unit represented by the following general formula (I), and further comprising at least one repeating structural unit selected from the group consisting of a repeating structural unit represented by the following general formula (II), a repeating structural unit represented by the following general formula (III), and a repeating structural unit represented by the following general formula (IV), wherein the content of the repeating structural unit represented by the general formula (I) is 40 mass% or more based on the total mass of the repeating structural units represented by the general formulas (I) to (IV), and the titration volume measured by a turbidity point titration method is 4.0 mL or more and 9.5 mL or less. [ka] (I) (In general formula (I), R 11 is a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 15 carbon atoms, or an aromatic hydrocarbon group, which may have a heteroatom. 11 may be the same or different.) [ka] (II) (In general formula (II), R 21is a divalent linear, branched or cyclic aliphatic hydrocarbon group having 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 21 may be the same or different. n21 is any integer.) [ka] (III) (In general formula (III), R 31 is a divalent linear, branched or cyclic aliphatic hydrocarbon group having 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 31 may be the same or different.) [ka] (IV) (In general formula (IV), R 41 and R 42 are each independently a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 41 and R 42 may be the same or different.) [3] The polycarbonate diol composition according to [1], wherein the content of the repeating structural unit represented by the general formula (I) is 5% by mass or more and 95% by mass or less based on the total mass of the repeating structural units represented by the general formulas (I) to (IV). [4] The polycarbonate diol composition according to any one of [1] to [3], wherein the content of the repeating structural unit represented by the general formula (I) is 40 mass% or more and 90 mass% or less based on the total mass of the repeating structural units represented by the general formulas (I) to (IV). [5] The polycarbonate diol composition according to any one of [1] to [4], having an acid value of 0.001 mg-KOH / g or more and 0.8 mg-KOH / g or less. [6] The polycarbonate diol composition according to any one of [1] to [5], having a peroxide content of 10 meq / kg or less. [7] The polycarbonate diol composition according to any one of [1] to [6], having a Hazen color number (APHA value) of 100 or less according to JIS K0071-1 (2017). [8] The polycarbonate diol composition according to any one of [1] to [7], wherein, among the repeating structural units represented by the general formulas (II) to (IV), the average repeat number n21 of the repeating structural units represented by the general formula (II) is 15 or more. [9] Among the repeating structural units represented by the general formulae (II) to (IV), any one of [1] to [8] containing at least a repeating structural unit represented by the general formula (II) or (IV). The polycarbonate diol composition according to any one of the preceding claims.

[10] The polycarbonate diol composition according to any one of [1] to [9], which contains at least a repeating structural unit represented by general formula (II) among the repeating structural units represented by general formulas (II) to (IV).

[11] A polyurethane obtained by using the polycarbonate diol composition according to any one of [1] to

[10] .

[12] The polyurethane according to

[11] , wherein a ΔM calculated by the following formula (B) for a stress at 100% elongation in a tensile test of the polyurethane is 1.0 or more and 19.0 or less. ΔM = M1 - M2 (B) (In formula (B), M1 represents the stress at 100% elongation in a tensile test at -20°C, and M2 represents the stress at 100% elongation in a tensile test at 23°C.)

[13]

[11] or

[12] . Synthetic leather comprising the polyurethane according to the present invention. Effect of the Invention

[0011] The polycarbonate diol composition of the present invention has excellent quality stability, is less colored, and has excellent compatibility with solvents and other polyols. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] 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 can be modified in various ways within the scope of the gist of the present invention.

[0013] [Polycarbonate diol composition] The first polycarbonate diol composition of the present embodiment contains a repeating structural unit represented by the following general formula (I) (hereinafter also simply referred to as "structural unit (I)"), and further contains at least one repeating structural unit selected from the group consisting of a repeating structural unit represented by the following general formula (II) (hereinafter also simply referred to as "structural unit (II)"), a repeating structural unit represented by the following general formula (III) (hereinafter also simply referred to as "structural unit (III)"), and a repeating structural unit represented by the following general formula (IV) (hereinafter also simply referred to as "structural unit (IV)"), and satisfies the following formula (Formula 1). [ka] (I) (In general formula (I), R 11 is a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 15 carbon atoms, or an aromatic hydrocarbon group, which may have a heteroatom. 11 may be the same or different.) [ka] (II) (In general formula (II), R 21 is a divalent linear, branched or cyclic aliphatic hydrocarbon group having 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 21may be the same or different. n21 is any integer.) [ka] (III) (In general formula (III), R 31 is a divalent linear, branched or cyclic aliphatic hydrocarbon group having 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 31 may be the same or different.) [ka] (IV) (In general formula (IV), R 41 and R 42 are each independently a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 41 and R 42 may be the same or different.) xy≧3.7×α (α=22.4×Mn -0.41 )...(Formula 1) (In formula 1, x is the ratio of the content (mass%) of the repeating structural unit represented by the general formula (I) to the total mass (mass%) of the repeating structural units represented by the general formulas (I) to (IV), y is the titration amount (mL) of the polycarbonate diol composition in a turbidity point titration method, and Mn is the number average molecular weight of the polycarbonate diol composition.)

[0014] The polycarbonate diol composition of the present embodiment has such characteristics, and therefore has excellent stability of quality and excellent compatibility with solvents and other polyols.

[0015] The second polycarbonate diol composition of the present embodiment contains a repeating structural unit represented by the following general formula (I) (hereinafter, also simply referred to as "structural unit (I)"), and further contains at least one repeating structural unit selected from the group consisting of a repeating structural unit represented by the following general formula (II) (hereinafter, also simply referred to as "structural unit (II)"), a repeating structural unit represented by the following general formula (III) (hereinafter, also simply referred to as "structural unit (III)"), and a repeating structural unit represented by the following general formula (IV) (hereinafter, also simply referred to as "structural unit (IV)"), and the content of the repeating structural unit represented by the general formula (I) is 40 mass% or more with respect to the total mass of the repeating structural units represented by the general formulas (I) to (IV), and the titration amount by a turbidity point titration method is 4.0 mL or more and 9.5 mL or less. [ka] (I) (In general formula (I), R 11 is a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 15 carbon atoms, or an aromatic hydrocarbon group, which may have a heteroatom. 11 may be the same or different.) [ka] (II) (In general formula (II), R 21 is a divalent linear, branched or cyclic aliphatic hydrocarbon group having 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 21 may be the same or different. n21 is any integer.) [ka] (III) (In general formula (III), R 31 is a divalent linear, branched or cyclic aliphatic hydrocarbon group having 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 31may be the same or different.) [ka] (IV) (In general formula (IV), R 41 and R 42 are each independently a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 41 and R 42 may be the same or different.)

[0016] The polycarbonate diol composition of the present embodiment has such characteristics, and therefore has excellent compatibility with solvents and other polyols.

[0017] The polycarbonate diol composition of the present embodiment is not particularly limited in the production method, and may be a copolymer of the structural unit (I) and at least one of the structural units (II) to (IV), or each of the structural units may exist independently.

[0018] Structural Units In the polycarbonate diol composition of this embodiment, the structural unit (I) will be described in detail below.

[0019] (R 11 ) In general formula (I), R 11 is a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 15 carbon atoms, or an aromatic hydrocarbon group, which may have a heteroatom. 11 may be the same as or different from each other.

[0020] R 11 The divalent linear aliphatic hydrocarbon group in has 2 or more and 15 or less carbon atoms, preferably 3 or more and 12 or less carbon atoms, and more preferably 3 or more and 10 or less carbon atoms.

[0021] R 11 Specific examples of the divalent linear aliphatic hydrocarbon group in are not particularly limited, but include, for example, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptylene group, an octylene group, etc. From the viewpoint of versatility, a trimethylene group, a butylene group, a pentylene group, a hexylene group, and a decamethylene group are preferred.

[0022] R 11 The divalent branched aliphatic hydrocarbon group in has 3 or more and 15 or less carbon atoms, preferably 3 or more and 12 or less carbon atoms, and more preferably 3 or more and 10 or less carbon atoms.

[0023] R 11 Specific examples of the divalent branched aliphatic hydrocarbon group in the formula (I) are not particularly limited, but include, for example, 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, from the viewpoint of versatility, an isobutylene group, an isopentylene group, or an isohexylene group is preferred.

[0024] R 11 The divalent cyclic aliphatic hydrocarbon group in 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.

[0025] R 11 Specific examples of the divalent cyclic aliphatic hydrocarbon group in the formula (I) are not particularly limited, but include, for example, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, etc. Among these, from the viewpoint of versatility, a cyclohexylene group is preferred.

[0026] R 11 The divalent aromatic hydrocarbon group in has 6 or more and 15 or less carbon atoms, preferably 6 or more and 12 or less carbon atoms, and more preferably 6 or more and 10 or less carbon atoms.

[0027] R11 Specific examples of the divalent aromatic hydrocarbon group in the formula (I) include, but are not limited to, a phenylene group, a naphthylene group, and the like.

[0028] R 11 Specific examples of the heteroatom in are not particularly limited, but include, for example, boron, oxygen, nitrogen, phosphorus, and sulfur. The heteroatom may have a five-membered heterocyclic structure such as oxolane, thiolane, and azolidine, or a six-membered heterocyclic structure such as oxane and pyridine.

[0029] Among them, R 11 As the divalent linear aliphatic hydrocarbon group, a divalent branched aliphatic hydrocarbon group having 3 to 10 carbon atoms is preferable, a divalent linear aliphatic hydrocarbon group having 4 to 6 carbon atoms is more preferable, and a butylene group, a pentylene group, or a hexylene group is even more preferable.

[0030] In the polycarbonate diol composition of the present embodiment, at least a part of the polycarbonate diol is represented by R 11 is preferably at least two or more selected from the group consisting of divalent linear and branched aliphatic hydrocarbon groups having from 2 to 15 carbon atoms. In this case, there is a tendency that a polycarbonate diol composition that is liquid at room temperature is obtained.

[0031] Furthermore, when the polycarbonate diol composition of the present embodiment contains a molecule having a structural unit represented by general formula (I), both ends of the molecule are preferably hydroxyl groups.

[0032] The molecule having a polycarbonate structure contained in the polycarbonate diol composition of this embodiment is preferably a polycarbonate diol having both ends thereof. That is, the molecule having a polycarbonate structure contained in the polycarbonate diol composition of this embodiment is preferably a polycarbonate diol. Due to impurities in various raw materials used in the production of the polycarbonate diol composition, terminal structures by-produced during the production of the polycarbonate diol composition, or due to the urethane reaction rate and state control in the use of the polycarbonate diol composition, some of the terminal hydroxyl groups may be converted to alkyl groups or aryl groups that do not react with isocyanate groups. In this embodiment, such cases are also taken into consideration, and the terminal groups of the polycarbonate diol include cases where 100 mol% of both ends are not strictly hydroxyl groups. From this viewpoint, the ratio of hydroxyl groups to the total molar amount of terminal groups is preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 98 mol% or more.

[0033] In this embodiment, the both terminal structures of the polycarbonate diol contained in the polycarbonate diol composition can be confirmed, for example, in accordance with the method for measuring the primary terminal OH ratio described in Japanese Patent No. 3874664 (Reference 1). However, as a solvent for recovering the fraction, in addition to ethanol, solvents such as tetrahydrofuran, acetone, and methanol can be used.

[0034] [Structural unit (II)] Next, the structural unit (II) will be described in detail below.

[0035] (R 21 ) In general formula (II), R 21 is a divalent linear, branched or cyclic aliphatic hydrocarbon group having 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 21 may be the same as or different from each other.

[0036] R 21The divalent linear aliphatic hydrocarbon group in has 2 or more and 20 or less carbon atoms, preferably 2 or more and 12 or less carbon atoms, and more preferably 2 or more and 6 or less carbon atoms.

[0037] R 21 Specific examples of the divalent linear aliphatic hydrocarbon group in the formula (I) include, but are not limited to, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptylene group, and an octylene group.

[0038] R 21 The divalent branched aliphatic hydrocarbon group in has 3 or more and 20 or less carbon atoms, preferably 3 or more and 12 or less carbon atoms, and more preferably 3 or more and 6 or less carbon atoms.

[0039] R 21 Specific examples of the divalent branched aliphatic hydrocarbon group in the formula (I) 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, and an isooctylene group.

[0040] R 21 The divalent cyclic aliphatic hydrocarbon group in has 6 or more and 20 or less carbon atoms, preferably 6 or more and 12 or less carbon atoms, and more preferably 6 or more and 8 or less carbon atoms.

[0041] R 21 Specific examples of the divalent cyclic aliphatic hydrocarbon group in the formula (I) include, but are not limited to, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, and a cycloheptylene group.

[0042] R 21 The divalent aromatic hydrocarbon group in has 6 or more and 15 or less carbon atoms, preferably 6 or more and 12 or less carbon atoms, and more preferably 6 or more and 10 or less carbon atoms.

[0043] R 21Specific examples of the divalent aromatic hydrocarbon group in the formula (I) include, but are not limited to, a phenylene group, a naphthylene group, and the like.

[0044] Among them, R 21 As the alkyl group, a divalent linear, branched or cyclic aliphatic hydrocarbon group having 2 to 20 carbon atoms (i.e., an alkylene group) is preferable, and a divalent linear aliphatic hydrocarbon group having 2 to 6 carbon atoms and / or a divalent branched aliphatic hydrocarbon group having 3 to 6 carbon atoms is more preferable.

[0045] (n21) In the general formula (II), n21 represents the structure (-R 21 In general formula (II), n21 represents the number of repetitions of -O-). In general formula (II), n21 is any integer, but the average value of n21 in the entire polycarbonate diol composition of this embodiment is preferably 12 or more, more preferably in the range of 12 to 70, even more preferably in the range of 12 to 60, even more preferably in the range of 15 or more, and particularly preferably in the range of 15 to 50.

[0046] When the average value of n21 in the entire polycarbonate diol composition of this embodiment is equal to or greater than the above lower limit, polyurethane with better flexibility and low-temperature flexibility tends to be obtained. Also, when the average value of n21 in the entire polycarbonate diol composition of this embodiment is equal to or less than the above upper limit, the viscosity of the polycarbonate diol composition tends to be lower.

[0047] The n21 can be determined by alkaline decomposition of the polycarbonate diol composition to extract the raw material diol component, and subjecting the component to GC-MS measurement, LC-MS measurement, and gel permeation chromatography (GPC) measurement. Specifically, it can be determined by the method described in the examples below.

[0048] Among these, the structural unit (II) is preferably a polyoxyalkylene structure.

[0049] Specific examples of preferred oxyalkylene groups contained in the structural unit (II) are not particularly limited, and include, for example, an oxyethylene group, an oxy1-methylethylene group, an oxytetramethylene group, an oxy2,2-dimethyltrimethylene group, etc. Among these, a structure containing an oxy1-methylethylene group is preferred, and an oxy1-methylethylene group and an oxyethylene group are particularly preferred.

[0050] [Structural unit (III)] Next, the structural unit (III) will be described in detail below.

[0051] (R 31 ) In general formula (III), R 31 is a divalent linear, branched or cyclic aliphatic hydrocarbon group having 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 31 may be the same as or different from each other.

[0052] R in general formula (III) 31 Although not particularly limited, examples of R include linear or branched alkylene groups having 2 to 20 carbon atoms. Specific examples of R include, but are not particularly limited to, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, propylene, isobutylene, 2-methyltetramethylene, 2-methylpentamethylene, 3-methylpentamethylene, isononamethylene, and 2-methylnonamethylene. In addition, R in the general formula (III) 31Although not particularly limited, examples of R include substituted or unsubstituted cycloalkylene groups having 3 to 20 carbon atoms. Specific examples include, but are not particularly limited to, a cyclopentylene group, a cyclohexylene group, a 1,2-dimethylenecyclopentane group, a 1,3-dimethylenecyclopentane group, a 1,2-dimethylenecyclohexane group, a 1,3-dimethylenecyclohexane group, a 1,4-dimethylenecyclohexane group, a 4,4'-methylenedicyclohexylene group, and a 2,2-dicyclohexylenepropane group. 31 Examples of the aryl group include, but are not limited to, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms. Specific examples of the aryl group include, but are not limited to, a phenylene group, a 1,2-dimethylenebenzene group, a 1,3-dimethylenebenzene group, a 1,4-dimethylenebenzene group, a naphthylene group, a 4,4'-methylenediphenylene group, and a 2,2-diphenylenepropane group.

[0053] Among these, from the viewpoints of improving the stain resistance and solvent resistance when made into polyurethane, and of the ease of obtaining the raw material, the cyclic ester compound, R 31 is preferably a pentamethylene group.

[0054] Structural Units (IV) Next, the structural unit (IV) will be described in detail below.

[0055] (R 41 ) In general formula (IV), R 41 are each independently a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 41 may be the same as or different from each other.

[0056] R in general formula (IV) 41Although not particularly limited, examples of R include linear or branched alkylene groups having 2 to 20 carbon atoms. Specific examples of R include, but are not particularly limited to, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, propylene, isobutylene, 2-methyltetramethylene, 2-methylpentamethylene, 3-methylpentamethylene, isononamethylene, and 2-methylnonamethylene. In addition, R in the general formula (IV) 41 Although not particularly limited, examples of R include substituted or unsubstituted cycloalkylene groups having 3 to 20 carbon atoms. Specific examples include, but are not particularly limited to, a cyclopentylene group, a cyclohexylene group, a 1,2-dimethylenecyclopentane group, a 1,3-dimethylenecyclopentane group, a 1,2-dimethylenecyclohexane group, a 1,3-dimethylenecyclohexane group, a 1,4-dimethylenecyclohexane group, a 4,4'-methylenedicyclohexylene group, and a 2,2-dicyclohexylenepropane group. 41 Examples of the aryl group include, but are not limited to, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms. Specific examples of the aryl group include, but are not limited to, a phenylene group, a 1,2-dimethylenebenzene group, a 1,3-dimethylenebenzene group, a 1,4-dimethylenebenzene group, a naphthylene group, a 4,4'-methylenediphenylene group, and a 2,2-diphenylenepropane group.

[0057] (R 42 ) In general formula (IV), R 42 is a divalent linear, branched or cyclic aliphatic hydrocarbon group having 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 42 may be the same as or different from each other.

[0058] R in general formula (IV) 42Although not particularly limited, examples of R include linear or branched alkylene groups having 2 to 20 carbon atoms. Specific examples of R include, but are not particularly limited to, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, propylene, isobutylene, 2-methyltetramethylene, 2-methylpentamethylene, 3-methylpentamethylene, isononamethylene, and 2-methylnonamethylene. In addition, R in the general formula (IV) 42 Although not particularly limited, examples of R include substituted or unsubstituted cycloalkylene groups having 3 to 20 carbon atoms. Specific examples include, but are not particularly limited to, a cyclopentylene group, a cyclohexylene group, a 1,2-dimethylenecyclopentane group, a 1,3-dimethylenecyclopentane group, a 1,2-dimethylenecyclohexane group, a 1,3-dimethylenecyclohexane group, a 1,4-dimethylenecyclohexane group, a 4,4'-methylenedicyclohexylene group, and a 2,2-dicyclohexylenepropane group. 42 Examples of the aryl group include, but are not limited to, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms. Specific examples of the aryl group include, but are not limited to, a phenylene group, a 1,2-dimethylenebenzene group, a 1,3-dimethylenebenzene group, a 1,4-dimethylenebenzene group, a naphthylene group, a 4,4'-methylenediphenylene group, and a 2,2-diphenylenepropane group.

[0059] [Structural unit (II)~Structural unit (IV)] The polycarbonate diol composition of the present embodiment contains at least one repeating structural unit selected from the group consisting of a repeating structural unit represented by the following general formula (II), a repeating structural unit represented by the following general formula (III), and a repeating structural unit represented by the following general formula (IV). [ka] (II) (In general formula (II), R 21is a divalent linear, branched or cyclic aliphatic hydrocarbon group having 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 21 may be the same or different. n21 is any integer.) [ka] (III) (In general formula (III), R 31 is a divalent linear, branched or cyclic aliphatic hydrocarbon group having 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 31 may be the same or different.) [ka] (IV) (In general formula (IV), R 41 and R 42 are each independently a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 41 and R 42 may be the same or different.)

[0060] In the polycarbonate diol composition of the present embodiment, the terminal structures of the structural units (II) to (IV) may be terminal structures in which one terminal is bonded to a carbonate group and the other terminal is bonded to a hydroxyl group, or both terminals are bonded to carbonate groups, or both terminals are bonded to hydroxyl groups.

[0061] In the polycarbonate diol composition of the present embodiment, the terminal structures of the structural units (II) to (IV) may be a mixture of an terminal structure in which one terminal is bonded to a carbonate group and the other terminal is bonded to a hydroxyl group, an terminal structure in which both terminals are bonded to carbonate groups, and an terminal structure in which both terminals are bonded to hydroxyl groups.

[0062] Among these, from the viewpoints of flexibility, low-temperature characteristics, and moist heat resistance, the polycarbonate diol composition of the present embodiment preferably contains the structural unit (II) or (IV) among the structural units (II) to (IV), and more preferably contains the structural unit (II).

[0063] [Cloudy point titration] The second polycarbonate diol composition of the present embodiment has a titration amount measured by a cloudy point titration method of 4.0 mL or more and 9.5 mL or less, and preferably 4.0 mL or more and 8.5 mL or less.

[0064] In this embodiment, the titration amount in the cloudy point titration method is the titration amount at the point when the polycarbonate diol composition starts to become cloudy when the polycarbonate diol composition is dissolved in butyl acetate, which is a good solvent, and the obtained solution is titrated with hexane, which is a poor solvent. If the polycarbonate diol composition is insoluble in butyl acetate, it may be dissolved in acetone. Specifically, it can be determined by the method described in the examples below.

[0065] This turbidity point titration evaluates the solubility in a solvent, and the results vary depending on the type, molecular weight, and structure of the polyol. In general, the smaller the molecular weight, the higher the solubility in the solvent, and the solubility also varies depending on the functional groups contained. Therefore, when it comes to polyols, there will be differences in solubility when two or more types of polyols are blended, and when the structure is changed by reacting them.

[0066] The second polycarbonate diol composition of the present embodiment has a titration amount by a turbidity point titration method of 4.0 mL or more and 9.5 mL or less, preferably 4.0 mL or more and 8.5 mL or less, more preferably 4.0 mL or more and 7.6 mL or less, and further preferably 4.1 mL or more and 7.4 mL or less.

[0067] When the titration amount in the turbidity point titration method is the above lower limit or more, the compatibility of the polycarbonate diol composition with the solvent and the raw materials used in synthesizing the polyurethane is improved, and when the titration amount in the turbidity point titration method is the above upper limit or less, a polyurethane having an excellent balance of low-temperature flexibility and durability such as chemical resistance and moist heat resistance is obtained, which is preferable.

[0068] In the polycarbonate diol composition, the method for controlling the titration amount in the turbidity point titration method within the above range is not particularly limited, but for example, a method of adjusting the charging ratio of the structural unit (I) and the structural units (II) to (IV) can be mentioned. In the method for producing the polycarbonate diol, a method of adjusting the reaction time or a method of appropriately adjusting the oxygen concentration during mixing and stirring can be mentioned.

[0069] In addition, by using this turbidity point titration method, the progress of the transesterification reaction can be evaluated, and by setting a target value for the titration amount in the turbidity point titration method, the variation in the transesterification reaction due to production lots can be reduced, and a polycarbonate diol composition with excellent quality stabilization tends to be obtained.

[0070] [Relationship formula (Equation 1)] The first polycarbonate diol composition of the present embodiment satisfies the following formula (Formula 1). xy≧3.7×α (α=22.4×Mn -0.41 )...(Formula 1) (In formula 1, x is the content (mass%) of the repeating structural unit represented by the general formula (I) relative to the total mass (mass%) of the repeating structural units represented by the general formulas (I) to (IV), y is the titration amount (mL) of the polycarbonate diol composition in a turbidity point titration method, and Mn is the number average molecular weight of the polycarbonate diol composition.)

[0071] Here, the number average molecular weight can be calculated from the hydroxyl value of the polycarbonate diol composition using the method described in the Examples below.

[0072] In turbidity point titration, compounds with smaller molecular weights generally have higher solubility in solvents, so the titration volume of the poor solvent tends to be higher. α is a factor that offsets the difference due to molecular weight.

[0073] Generally, polycarbonate diol has low solubility in solvent, so that when x is large, y tends to be small. It is presumed that the more the repeating structural units represented by the general formulas (I) to (IV) and the repeating structural unit represented by the general formula (I) are randomly present, the more the titration amount of the turbidity point titration becomes. In addition, the method of obtaining the polycarbonate diol composition satisfying the above formula (Formula 1) is not particularly limited, but for example, a method of appropriately setting the reaction time until the modification is sufficiently progressed can be mentioned.

[0074] [Content of structural unit (I)] In the polycarbonate diol composition of the present embodiment, the content of the structural unit (I) is preferably 5% by mass or more and 95% by mass or less, more preferably 20% by mass or more and 90% by mass or less, and even more preferably 40% by mass or more and 90% by mass or less, based on the total mass of the structural units (I) to (IV). The content of the structural unit (I) is preferably equal to or more than the above lower limit, since it is possible to obtain a polyurethane having better durability such as chemical resistance and wet heat resistance. In addition, the content of the structural unit (I) is preferably equal to or less than the above upper limit, so that the viscosity of the polycarbonate diol composition tends to be lower. The content of the structural unit (I) can be measured by the method described in the Examples below.

[0075] [Number average molecular weight] The number average molecular weight of the polycarbonate diol composition of this embodiment is preferably 250 to 10,000, more preferably 400 to 8,000, even more preferably 500 to 5,000, and particularly preferably 500 to 3,000. The number average molecular weight of the polycarbonate diol composition of this embodiment is the upper limit or less, so that the viscosity is reduced and the handling property during polyurethane production tends to be improved. In addition, the number average molecular weight is the lower limit or more, so that the polyurethane produced using the polycarbonate diol composition of this embodiment tends to have excellent flexibility.

[0076] The method for controlling the number average molecular weight of the polycarbonate diol composition of the present embodiment within the above range is not particularly limited, and examples thereof include a method using a structural unit (I) whose number average molecular weight is controlled within the above range and at least one of the structural units (II) to (IV) whose number average molecular weight is controlled within the above range, a method using a structural unit (I) whose number average molecular weight is larger than the above range and at least one of the structural units (II) to (IV) whose number average molecular weight is smaller than the above range, a method in which a reaction is carried out while checking the number average molecular weight, and the reaction is stopped when the number average molecular weight reaches within the above range, and the like.

[0077] In this embodiment, the number average molecular weight of the polycarbonate diol composition can be measured by the method described in the Examples below.

[0078] [Acid value] The acid value of the polycarbonate diol composition of the present embodiment is preferably 0.001 mg-KOH / g or more and 0.8 mg-KOH / g or less, more preferably 0.005 mg-KOH / g or more and 0.6 mg-KOH / g or less, and even more preferably 0.01 mg-KOH / g or more and 0.6 mg-KOH / g or less. Since it is difficult to remove all acidic compounds derived from raw materials, catalysts, additives, etc., it is preferable from the viewpoint of productivity of the polycarbonate diol composition to have an acid value of the above lower limit value or more, and the occurrence of coloring tends to be reduced by having an acid value of the above upper limit value or less.

[0079] The method for controlling the acid value of the polycarbonate diol composition within the above range is not particularly limited, but examples thereof include a method of adjusting the acid value of the raw material during the production of the polycarbonate diol composition and a method of appropriately selecting the addition of a catalyst poison to deactivate the catalyst.

[0080] In this embodiment, the acid value of the polycarbonate diol composition can be measured by the method described in the Examples below.

[0081] [Peroxide value] The peroxide content (hereinafter also referred to as "peroxide value") of the polycarbonate diol composition of this embodiment is preferably 10 meq / kg or less, more preferably 3 meq / kg or less. When the polycarbonate diol composition of this embodiment has a peroxide value of 10 meq / kg or less, coloration tends to be suppressed. The lower limit of the peroxide value of the polycarbonate diol composition of this embodiment is not particularly limited, but is, for example, 0.01 meq / kg. The peroxide value can be measured by a sodium thiosulfate titration method in which potassium iodide is reacted with oxidized fats and oils in an acidic state, and the liberated iodine is measured by a titration method, but it can be easily measured by using a test paper for measuring peroxide value (product name: "POV test paper", manufactured by Shibata Chemical Co., Ltd.). Specifically, it can be measured by the method described in the examples below.

[0082] The method for controlling the peroxide value of the polycarbonate diol composition within the above range is not particularly limited, but examples thereof include a method of setting the reaction temperature to 200° C. or lower to reduce oxidative cleavage due to thermal decomposition, a method of setting the oxygen concentration to 0.5% or lower during the production of the polycarbonate diol composition, and a method of setting the nitrogen flow rate to 0.1 L / min or more and 50 L / min or less during the production, and the above methods may be combined.

[0083] [APHA] The Hazen color number (hereinafter also referred to as "APHA") value of the polycarbonate diol composition of this embodiment (APHA value: JIS K0071-1 (2017)) is preferably 100 or less, more preferably 60 or less, and even more preferably 50 or less. The lower the APHA value, the better the color tone of the polycarbonate diol composition itself and the polyurethane obtained using this polycarbonate diol composition. The lower limit of the APHA value is not particularly limited, but is, for example, 0.

[0084] A polycarbonate diol composition satisfying such an APHA value can be produced by making the APHA of the raw material used 100 or less, and in the production method of the polycarbonate diol used in the present embodiment described later, it becomes more effective to make the oxygen concentration during mixing and stirring 0.5% or less.

[0085] In this embodiment, the APHA value can be measured by the method described in the Examples below.

[0086] <Method for producing polycarbonate diol composition> The method for producing the polycarbonate diol composition of the present embodiment is not particularly limited as long as it satisfies the above characteristics. For example, a method of carrying out an ester exchange reaction using a polycarbonate diol represented by the following general formula (I-1) (hereinafter, may be referred to as "polycarbonate diol (I-1)") and at least one selected from the group consisting of an ether diol represented by the following general formula (II-1) (hereinafter, may be referred to as "ether diol (II-1)"), a polycaprolactone diol represented by the following general formula (III-1) (hereinafter, may be referred to as "lactone diol (III-1)"), and a polyester diol represented by the following general formula (IV-1) (hereinafter, may be referred to as "ester diol (IV-1)"), or a method of reacting a polycarbonate diol (I-1) with a cyclic ester compound. [ka] (I-1) (In general formula (I-1), R 111 and R 112 are the above R 11 where n11 is an arbitrary integer.) [ka] (II-1) (In general formula (II-1), R 211 is the above R 21 (n211 is the same as n21 above.) [ka] (III-1) (In general formula (III-1), R 311 is the above R 31 (n311 is an arbitrary integer) [ka] (IV-1) (In general formula (IV-1), R 411 and R 421 are the above R 41 and R 42 where n411 is an arbitrary integer.)

[0087] [Polycarbonate diol (I-1)] The polycarbonate diol (I-1) used in the production of the polycarbonate diol composition of the present embodiment may have a structure represented by the above general formula (I-1). The method for producing the polycarbonate diol (I-1) is not particularly limited, and a known method can be adopted. For example, the polycarbonate diol (I-1) can be obtained by reacting a carbonate compound with a diol compound in the presence of an ester exchange catalyst.

[0088] (Carbonate compounds) The carbonate compound used in the production of the polycarbonate diol (I-1) is not limited to the following, but examples thereof include alkylene carbonates, dialkyl carbonates, diaryl carbonates, and the like.

[0089] 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.

[0090] The dialkyl carbonate is not particularly limited, but examples thereof include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and dibutyl carbonate.

[0091] The diaryl carbonate is not particularly limited, but examples thereof include diphenyl carbonate.

[0092] Among these, the carbonate compound used in the production of the polycarbonate diol (I-1) is preferably ethylene carbonate, dimethyl carbonate, diethyl carbonate, or diphenyl carbonate, and more preferably ethylene carbonate.

[0093] (Diol Compound) The diol compound used in the production of the polycarbonate diol (I-1) is not limited to the following, but examples thereof include linear diols, branched diols, cyclic diols, and diols having an aromatic ring.

[0094] 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.

[0095] 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.

[0096] The cyclic diol is not particularly limited, but examples thereof include 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2-bis(4-hydroxycyclohexyl)-propane, and the like.

[0097] The diol having an aromatic ring is not particularly limited, but examples thereof include p-xylenediol, p-tetrachloroxylenediol, 1,4-bis(hydroxyethoxy)benzene, and 2,2-bis[(4-hydroxyethoxy)phenyl]propane.

[0098] Among these, linear or branched diols having 3 to 10 carbon atoms are preferred, and 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nanodiol, 1,10-decanediol, 2-methyl-1,3-propanediol, and 3-methyl-1,5-pentanediol are preferred, with 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol being more preferred.

[0099] [Production conditions of polycarbonate diol composition and polycarbonate diol (I-1)] In producing the raw material polycarbonate diol (I-1), a transesterification catalyst can be used. The catalyst can be selected from ordinary transesterification catalysts.

[0100] 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.

[0101] 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.

[0102] The alkali metal is not particularly limited, but examples thereof include lithium, sodium, and potassium.

[0103] The alkaline earth metal is not particularly limited, but examples thereof include magnesium, calcium, strontium, barium, and the like.

[0104] In addition, 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 an alkali metal or an alkaline earth metal, as well as salts thereof, alcoholates thereof, and organic compounds containing the metals.

[0105] 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.

[0106] These transesterification catalysts can be used alone or in combination of two or more.

[0107] Among them, as the transesterification reaction catalyst, 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 are preferred, because the transesterification reaction to obtain a polycarbonate diol is carried out more satisfactorily and the effect on the urethane reaction is smaller when the obtained polycarbonate diol is used.

[0108] The transesterification catalyst is more preferably one or more metals selected from the group consisting of magnesium, titanium, ytterbium, tin and zirconium.

[0109] Specific examples of preferred transesterification catalysts include, but are not limited to, organic compounds of magnesium, organic compounds of lead, and organic compounds of titanium.

[0110] The organic compound of magnesium is not particularly limited, but examples thereof include magnesium acetate tetrahydrate, magnesium acetate anhydrate, and the like.

[0111] The organic lead compound is not particularly limited, but examples thereof include lead acetate trihydrate, tetraphenyl lead, and lead stearate.

[0112] The organic titanium compound is not particularly limited, but examples thereof include titanium tetra-n-butoxide, titanium tetra-n-propoxide, titanium tetraisopropoxide, and the like.

[0113] The amount of the transesterification catalyst used is preferably from 0.00001% by mass to 0.1% by mass, and more preferably from 0.0001% by mass to 0.05% by mass, based on the total mass of the raw materials.

[0114] When the 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, so 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 measured by ICP (Inductively Coupled Plasma) emission spectroscopy.

[0115] The polycarbonate diol (I-1) used in the production of the polycarbonate diol composition of the present embodiment may contain a catalyst poison such as a phosphoric acid ester compound in order to deactivate the transesterification catalyst used in the production.

[0116] When the raw material polycarbonate diol (I-1) contains a catalyst poison of the transesterification catalyst used in its production, the transesterification reaction between the ether diol (II-1) or the ester diol (IV-1) and the polycarbonate diol (I-1) tends to be difficult to proceed. Therefore, when producing the polycarbonate diol composition of this embodiment, the above-mentioned transesterification catalyst can be newly added in a required amount.

[0117] On the other hand, when the raw material polycarbonate diol (I-1) does not contain the catalytic poison of the transesterification catalyst, the transesterification reaction in this embodiment tends to proceed easily. However, when the reaction temperature in the production process of the polycarbonate diol composition of this embodiment is to be lowered or the reaction time is to be shortened, 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 raw material polycarbonate diol (I-1) can be used.

[0118] The polycarbonate diol (I-1) used in the production of the polycarbonate diol composition of the present embodiment may be a homopolycarbonate diol obtained from one kind of diol compound, or a copolymer polycarbonate diol obtained from two or more kinds of diol compounds.

[0119] Any of the above-listed polycarbonate diols (I-1) can be used to obtain a polycarbonate diol composition by transesterification.

[0120] However, for example, homo-polycarbonate diol obtained by using 1,6-hexanediol, which is widely used in the market, is usually solid at room temperature, and therefore, the polycarbonate diol composition obtained by transesterification with the homo-polycarbonate diol also tends to be solid at room temperature.

[0121] On the other hand, for example, a copolymer polycarbonate diol obtained by using any two of 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol is liquid at room temperature, and therefore, a polycarbonate diol composition obtained by transesterification with the copolymer polycarbonate diol also tends to be liquid at room temperature.

[0122] (n11) In the general formula (I-1), n11 represents a carbonate structure (-R 111 n11 represents the number of repetitions of the formula (-O-CO-O-). n11 is an arbitrary integer, but the average value of n11 is preferably in the range of 1 to 50, more preferably in the range of 2 to 50, even more preferably in the range of 3 to 30, and particularly preferably in the range of 4 to 20.

[0123] The number average molecular weight of the polycarbonate diol (I-1) used in the production of the polycarbonate diol composition of the present embodiment is not particularly limited, but is preferably 500 or more and 5,000 or less, and more preferably 1,000 or more and 3,000 or less.

[0124] By the number average molecular weight of the polycarbonate diol (I-1) being the above lower limit or more, the performance expected of the polycarbonate diol composition tends to be improved. On the other hand, by the number average molecular weight of the polycarbonate diol (I-1) being the above upper limit or less, it is preferable in terms of handling during the production of the polycarbonate diol composition.

[0125] [Ether diol (II-1)] The ether diol (II-1) used in the production of the polycarbonate diol composition of this embodiment may have a structure represented by the above general formula (II-1). Among them, the ether diol (II-1) is preferably a polyoxyalkylene diol having primary hydroxyl groups at both ends. As the ether diol (II-1), products of various molecular weights are commercially available, and such commercially available products can also be used. The commercially available ether diol (II-1) is not particularly limited, but examples thereof include polyoxyalkylene diols such as the "Newpol" series, "Primepol" series, and "Sunnix" series manufactured by Sanyo Chemical Industries, Ltd., the "Pronon" series manufactured by NOF Corporation, the "Preminol" and "Exenol" series manufactured by AGC Inc., and the "PTMG" series manufactured by Mitsubishi Chemical Corporation, and polyether glycols such as PTXG manufactured by Asahi Kasei Corporation.

[0126] The number average molecular weight of the ether diol (II-1) is not particularly limited, but is preferably 400 to 3000, more preferably 600 to 2500. When the number average molecular weight of the ether diol (II-1) used in the production is the above lower limit or more, the flexibility tends to be improved when used in polyurethane, and when the number average molecular weight of the ether diol (II-1) is the above upper limit or less, the crystallinity of the polycarbonate diol composition of the present embodiment tends to be suppressed.

[0127] [Polycaprolactone diol (III-1) and cyclic ester compound] The polycaprolactone diol (III-1) used in the production of the polycarbonate diol composition of the present embodiment may have a structure represented by the above general formula (III-1). Among them, the polycaprolactone diol (III-1) is commercially available in various molecular weights, and such commercially available products can also be used. The commercially available products are not particularly limited, but include, for example, the "Placcel" series manufactured by Daicel Organic Synthesis Company, Ltd., and the "Polylite" series manufactured by DIC Corporation.

[0128] (n311) In the general formula (III-1), n311 represents the structure (-R 311 In general formula (III-1), n311 is any integer, but the average value of n311 is 1 or more, preferably in the range of 1 to 50, more preferably in the range of 1 to 30, and particularly preferably in the range of 1 to 20.

[0129] The number average molecular weight of the polycaprolactone diol (III-1) is not particularly limited, but is preferably from 400 to 3000, more preferably from 600 to 2000. When the number average molecular weight of the lactone diol (III-1) used in the production is equal to or more than the above lower limit, the flexibility of the polyurethane obtained from the polycarbonate diol composition of this embodiment tends to be improved, and when the number average molecular weight of the lactone diol (III-1) is equal to or less than the above upper limit, the viscosity of the polycarbonate diol composition of this embodiment tends to be lower.

[0130] Furthermore, a cyclic ester compound may be subjected to ring-opening polymerization.

[0131] The cyclic ester compound is not particularly limited, and examples thereof include cyclic ester compounds having 3 to 12 carbon atoms, such as β-propiolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, β-butyrolactone, γ-valerolactone, α-methyl-ε-caprolactone, β-methyl-ε-caprolactone, γ-methyl-ε-caprolactone, β,δ-dimethyl-ε-caprolactone, 3,3,5-trimethyl-ε-caprolactone, and enantholactone (7-heptalidone). 31 It is preferable to use ε-caprolactone which gives the structural unit (III) in which is a linear alkylene group having 5 carbon atoms.

[0132] [Ester diol (IV-1)] The ester diol (IV-1) used in the production of the polycarbonate diol composition of this embodiment may have a structure represented by the above general formula (IV-1). Among them, the ester diol (IV-1) is commercially available in various molecular weights, and such commercially available products can also be used. The commercially available ether diol (II-1) is not particularly limited, but examples thereof include the "Polylite" series manufactured by DIC Corporation, the "Kuraray Polyol" series manufactured by Kuraray Co., Ltd., the "Nipporun" series manufactured by Tosoh Corporation, and the "Adekanyu Ace" series manufactured by ADEKA Corporation.

[0133] (n411) In the general formula (IV-1), n411 represents the structure (-CO-R 411 -CO-OR 421 In general formula (IV-1), n411 is any integer, but the average value of n411 is 1 or more, preferably in the range of 1 to 50, more preferably in the range of 2 to 30, and particularly preferably in the range of 4 to 20.

[0134] The number average molecular weight of the ester diol (IV-1) is not particularly limited, but is preferably 400 to 3000, more preferably 600 to 2000. When the number average molecular weight of the ester diol (IV-1) used in the production is the above lower limit or more, the flexibility of the polyurethane obtained from the polycarbonate diol composition of this embodiment tends to be improved, and when the number average molecular weight of the ester diol (IV-1) is the above upper limit or less, the viscosity of the polycarbonate diol composition of this embodiment tends to be lower.

[0135] The method for producing the polycarbonate diol composition of the present embodiment is not particularly limited, but it is preferable to produce the composition by mixing the polycarbonate diol (I-1) with at least one compound selected from the group consisting of the ether diol (II-1), the ester diol (IV-1) and a cyclic ester compound, and stirring the mixture while heating.

[0136] The temperature during the reaction is not particularly limited, but is preferably 120° C. or higher and 200° C. or lower, more preferably 140° C. or higher and 180° C. or lower.

[0137] By setting the reaction temperature to the above lower limit or more, the transesterification reaction can be carried out in a shorter time, which tends to be economically advantageous. By setting the reaction temperature to the above upper limit or less, the acid value of the resulting polycarbonate diol composition can be controlled within a specific range, and coloration can be more effectively prevented.

[0138] In addition, during production, the oxygen concentration is preferably 0.5% or less. The method for reducing the oxygen concentration to 0.5% or less is not particularly limited, but examples include replacing the atmosphere of the reaction apparatus with nitrogen by 1.5 times or more, and then reacting while flowing nitrogen, or reducing the pressure to 0.1 kPa.s or less, replacing with nitrogen, and reacting under slightly reduced pressure. By reducing the oxygen concentration to 0.5% or less, the generation of peroxides is suppressed, and coloring of the resulting polycarbonate diol composition tends to be prevented.

[0139] In order to keep the oxygen concentration at 0.5% or less, it is preferable to flow nitrogen at a flow rate of 0.1 L / min to 50 L / min, and more preferably at a flow rate of 0.2 L / min to 30 L / min. By having the nitrogen flow rate be equal to or more than the lower limit, it is possible to prevent oxygen from being mixed in, and by having the nitrogen flow rate be equal to or less than the upper limit, it is possible to prevent the volatilization of the raw material diol, and it tends to be possible to keep the hydroxyl value of the obtained polycarbonate diol composition constant.

[0140] [Application] The polycarbonate diol composition of the present embodiment can be used as a raw material for polyurethane to be reacted with polyisocyanate. The polyurethane obtained by using the polycarbonate diol composition of the present embodiment has excellent chemical resistance, heat resistance, and weather resistance, and can be widely used in foams, elastomers, paints, coating agents, adhesives, adhesives, artificial leather, synthetic leather, water-based polyurethane paints, etc. Furthermore, it can be used as a modifier for polyesters and polyimides, etc.

[0141] [Polyurethane] The polyurethane of the present embodiment is formed using the above-mentioned polycarbonate diol composition.

[0142] [ΔStress at 100% elongation] For the polyurethane of this embodiment, for the stress at 100% elongation in a tensile test, ΔM calculated by the following formula (B) is preferably 1.0 or more and 19.0 or less, more preferably 3.5 or more and 18.5 or less, and even more preferably 5.0 or more and 17.0 or less. ΔM = M1 - M2 (B) (In formula (B), M1 represents the stress at 100% elongation in a tensile test at -20°C, and M2 represents the stress at 100% elongation in a tensile test at 23°C.)

[0143] The polyurethane of the present embodiment, since ΔM is equal to or greater than the above lower limit, tends to have an excellent balance between flexibility and durability. Also, since ΔM is equal to or less than the above upper limit, the polyurethane of the present embodiment tends to have excellent mechanical properties at low temperatures because the difference in elastic modulus due to temperature is small.

[0144] The method for producing the polyurethane of the present embodiment uses known polyurethane reaction conditions for producing ordinary polyurethanes, and can be carried out in the absence of a solvent or in the presence of a solvent.

[0145] Examples of the method include, but are not limited to, a method in which the above-mentioned polycarbonate diol composition, other polyol, polyisocyanate and chain extender are mixed together and reacted (hereinafter, may be referred to as a "one-shot method"), a method in which the above-mentioned polycarbonate diol composition, other polyol and polyisocyanate are reacted to prepare a prepolymer having isocyanate groups at both ends, and then the prepolymer is reacted with a chain extender (hereinafter, may be referred to as a "prepolymer method").

[0146] The isocyanate compound contained in the polyurethane of the present embodiment is not particularly limited as long as it acts as a curing agent, and one having two or more isocyanate groups at its terminals is used.

[0147] Such an isocyanate compound is not particularly limited, but examples thereof include linear aliphatic diisocyanates, cyclic aliphatic diisocyanates, aromatic diisocyanates, and isocyanate compounds having three or more isocyanate groups, as well as isocyanurate-modified products and biuret-modified products of these isocyanate compounds.

[0148] The chain aliphatic diisocyanate is not particularly limited, but examples thereof include hexamethylene diisocyanate and trimethylhexamethylene diisocyanate.

[0149] The cyclic aliphatic diisocyanate is not particularly limited, but examples thereof include isophorone diisocyanate, 1,4-cyclohexane diisocyanate, 1-methyl-2,4-cyclohexane diisocyanate, 1-methyl-2,6-cyclohexane diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate.

[0150] The aromatic diisocyanate is not particularly limited, but examples thereof include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate (hereinafter sometimes abbreviated as "MDI"), xylylene diisocyanate, and naphthylene diisocyanate.

[0151] The isocyanate compound having three or more isocyanate groups is not particularly limited, but examples thereof include triphenylmethane-4,4'-4''-triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatobenzene, and 4,4'-dimethyldiphenylmethane-2,2',5,5'-tetraisocyanate.

[0152] The isocyanate compound may be a commercially available product or may be synthesized by a known method.

[0153] The content of the isocyanate compound may be adjusted appropriately according to the molar amount of the hydroxyl group of the polyol, which is the main component. Specifically, the molar ratio (NCO / OH) of the isocyanate group of the isocyanate compound to the hydroxyl group of the polycarbonate diol can be, for example, 0.2 or more and 5.0 or less, for example, 0.4 or more and 3.0 or more, for example, 0.5 or more and 2.0 or less. When NCO / OH is equal to or more than the lower limit, a tougher coating film tends to be obtained. On the other hand, when NCO / OH is equal to or less than the upper limit, the smoothness of the coating film tends to be improved.

[0154] The chain extender used in producing the polyurethane of the present embodiment is not particularly limited, but examples thereof include ordinary polyols and polyamines.

[0155] The polyol is not particularly limited, but examples thereof include linear diols, branched diols, cyclic diols, and diols having an aromatic ring.

[0156] The linear diol is not particularly limited, but examples thereof include ethylene glycol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nanonediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol.

[0157] 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.

[0158] The cyclic diol is not particularly limited, but examples thereof include 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2-bis(4-hydroxycyclohexyl)-propane, and the like.

[0159] The diol having an aromatic ring is not particularly limited, but examples thereof include p-xylenediol, p-tetrachloroxylenediol, 1,4-bis(hydroxyethoxy)benzene, and 2,2-bis[(4-hydroxyethoxy)phenyl]propane.

[0160] The polyamine is not particularly limited, but examples thereof include hydroxyamines and polyamines.

[0161] The hydroxyamines are not particularly limited, but examples thereof include N-methylethanolamine, N-ethylethanolamine, and the like.

[0162] Examples of polyamines include, but are not limited to, ethylenediamine, 1,3-diaminopropane, hexamethylenediamine, triethylenetetramine, diethylenetriamine, isophoronediamine, 4,4'-diaminodicyclohexylmethane, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, 4,4'-diphenylmethanediamine, methylenebis(o-chloroaniline), xylylenediamine, diphenyldiamine, tolylenediamine, hydrazine, piperazine, and N,N'-diaminopiperazine.

[0163] These chain extenders may be used alone or in combination of two or more kinds.

[0164] [Synthetic leather] The synthetic leather of the present embodiment contains the above-mentioned polyurethane.

[0165] The synthetic leather of the present embodiment is not particularly limited, but may be, for example, a synthetic leather in which a base fabric, an adhesive layer, an intermediate layer, and a skin layer are laminated in this order. In such synthetic leather, it is preferable that at least one selected from the group consisting of the base fabric, the adhesive layer, the intermediate layer, and the skin layer contains the above-mentioned polyurethane.

[0166] As the base fabric (substrate), various materials can be used, and examples thereof include, but are not limited to, fibrous substrates. As the fibrous substrate, examples include, but are not limited to, fiber aggregates in which fibers are shaped into nonwoven fabrics, woven fabrics, net fabrics, etc., or fiber aggregates in which each fiber is bonded with an elastic polymer. As the fibers used in this fiber aggregate, examples include, but are not limited to, natural fibers such as cotton, hemp, and wool, regenerated or semi-synthetic fibers such as rayon and acetate, and synthetic fibers such as polyamide, polyester, polyacrylonitrile, polyvinyl alcohol, and polyolefin. These fibers may be single spun fibers or mixed spun fibers. As other substrates, examples include, but are not limited to, paper, release paper, plastic films of polyester or polyolefin, metal plates such as aluminum, glass plates, etc.

[0167] In the synthetic leather of this embodiment, it is preferable to use the above-mentioned polyurethane in the adhesive layer, intermediate layer, and surface layer. When forming each layer, crosslinking agents, other resins, antioxidants, ultraviolet absorbers, hydrolysis inhibitors, pigments, dyes, colorants, flame retardants, organic solvents, etc. can be added as necessary.

[0168] The method for producing the synthetic leather of the present embodiment is not particularly limited as long as the above-mentioned polyurethane is used, and any known method for producing synthetic leather can be used.

[0169] [Paint or coating composition] The paint or coating composition (paint) of the present embodiment is formed using the polycarbonate diol composition described above.

[0170] The method for producing the paint or coating composition (paint) using the above-mentioned polycarbonate diol composition can be a known production method in the industry.For example, the following can be produced: a two-liquid type solvent-based coating composition, which is obtained by mixing the paint base material obtained from the above-mentioned polycarbonate diol composition with a curing agent made of polyisocyanate just before coating; a one-liquid type solvent-based coating composition, which is made of a urethane prepolymer having an isocyanate terminal group obtained by reacting the above-mentioned polycarbonate diol with polyisocyanate; a one-liquid type solvent-based coating composition, which is made of a polyurethane resin obtained by reacting the above-mentioned polycarbonate diol, organic polyisocyanate and chain extender.

[0171] To the paint or coating composition (paint) of this embodiment, for example, other additives such as a curing accelerator (catalyst), a leveling agent, a filler, a dispersant, a flame retardant, a dye, an organic or inorganic pigment, a release agent, a flowability modifier, a plasticizer, an antioxidant, an ultraviolet absorber, a light stabilizer, an antifoaming agent, a colorant, a solvent, etc. can be added depending on various applications. By appropriately adding these other additives, paint compositions with different properties such as a soft-feel paint and a clear paint can be obtained.

[0172] The curing accelerator (catalyst) is not particularly limited, but examples thereof include commonly used ones such as monoamines, diamines, other triamines, cyclic amines, alcohol amines, ether amines, and metal catalysts.

[0173] The monoamine is not particularly limited, but examples thereof include triethylamine, N,N-dimethylcyclohexylamine, etc. The diamine is not particularly limited, but examples thereof include tetramethylethylenediamine, etc.

[0174] The alcohol amine is not particularly limited, but examples thereof include dimethylethanolamine.

[0175] The metal catalyst is not particularly limited, but examples thereof include potassium acetate, potassium 2-ethylhexanoate, calcium acetate, lead octoate, dibutyltin dilaurate, tin octoate, bismuth neodecanoate, bismuth oxycarbonate, bismuth 2-ethylhexanoate, zinc octoate, zinc neodecanoate, phosphine, and phospholine.

[0176] Specific examples of the organic solvent include, but are not limited to, amide-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, carbonate-based solvents, and aromatic hydrocarbon-based solvents.

[0177] These organic solvents may be used alone or as a mixed solvent of two or more kinds. EXAMPLES

[0178] Hereinafter, the present embodiment will be described in more detail with reference to specific examples and comparative examples, but the present embodiment is not limited by these examples and comparative examples as long as the gist of the present embodiment is not exceeded. In the present examples, "parts" and "%" are based on mass unless otherwise specified.

[0179] The physical properties and evaluations in the examples and comparative examples described later were measured and evaluated by the methods shown below.

[0180] [Physical Property 1] Hydroxyl value The hydroxyl value of the polycarbonate diol (composition) was measured by the following method. First, an acetylation reagent was prepared by adding pyridine to 12.5 g of acetic anhydride in a measuring flask to make 50 mL. Then, 2.5 g of sample was precisely weighed into a 100 mL eggplant flask. Then, 5 mL of acetylation reagent and 10 mL of toluene were added to the eggplant flask using a volumetric pipette, and a cooling tube was attached and the solution in the eggplant flask was stirred and heated at 100°C for 1 hour. Then, 2.5 mL of distilled water was added to the eggplant flask using a volumetric pipette, and the solution in the eggplant flask was heated and stirred for another 10 minutes. After the solution in the eggplant flask was cooled for 2 to 3 minutes, 12.5 mL of ethanol was added to the eggplant flask. Then, 2 to 3 drops of phenolphthalein were added to the eggplant flask as an indicator, and titrated with 0.5 mol / L ethanolic potassium hydroxide. Next, 5 mL of the acetylation reagent, 10 mL of toluene, and 2.5 mL of distilled water were placed in a 100 mL recovery flask, and the solution in the recovery flask was heated and stirred for 10 minutes, and then titration was performed in the same manner (blank test). Based on this result, the hydroxyl value of the polycarbonate diol (composition) was calculated using the following formula (i). Hydroxyl number (mg-KOH / g) = {(FE) × 28.05 × f} / G (i) In the formula (i), E represents the titer of the sample (mL), F represents the titer of the blank test (mL), G represents the sample mass (g), and f represents the factor of the titrant.

[0181] [Physical properties 2] Number average molecular weight (A) The number average molecular weight (A) of the polycarbonate diol (composition) was calculated from the hydroxyl value obtained in [Physical Properties 1] using the following formula (ii). Number average molecular weight (A)=2 / (H×10 -3 / 56.11) (ii) In the formula (ii), H represents the hydroxyl value (mg-KOH / g) of the polycarbonate diol (composition). In the examples and comparative examples described later, the number average molecular weight Mn of the polycarbonate diol composition applied to the following formula 1 was the number average molecular weight (A) calculated using the above formula (ii). xy≧3.7×α (α=22.4×Mn-0.41 )...(Formula 1) (In formula 1, x is the ratio of the content (mass%) of the repeating structural unit represented by the general formula (I) to the total mass (mass%) of the repeating structural units represented by the general formulas (I) to (IV), y is the titration amount (mL) of the polycarbonate diol composition by the cloud point titration method, and Mn is the number average molecular weight of the polycarbonate diol composition.)

[0182] [Physical property 3] Molecular weight (B) A portion of the polyurethane film obtained in the application examples and application comparison examples described below was cut out, and a N,N-dimethylformamide solution was prepared so that the polyurethane concentration was 0.1% by mass. Using a GPC device (Tosoh Corporation, product name "HLC-8320" (column: Tskgel SuperHM-H x 4), and a solution of 2.6 g of lithium bromide dissolved in 1 L of dimethylformamide as the eluent), the number average molecular weight (Mn) and weight average molecular weight (Mw) of the polyurethane were measured in terms of standard polystyrene. The molecular weight distribution (Mw / Mn) was also calculated from these measurement results.

[0183] [Physical Property 4] Hazen Color Number (APHA) In accordance with JIS K0071-1 (2017), the APHA of the polycarbonate diol composition obtained in the examples and comparative examples described below was measured by comparing with the standard solution placed in a colorimetric tube. The reagent used was a color standard solution of 1000 degrees (Fujifilm Wako Pure Chemical Industries, Ltd.). In addition, solutions were prepared in increments of 5 up to APHA30 and evaluated. In the case of a slightly turbid liquid, it was heated to 60°C and dissolved before measurement.

[0184] [Physical property 5] Turbidity point titration Under the condition of 25°C, 0.5 g of the polycarbonate diol composition obtained in the examples and comparative examples described below was dissolved in 8.8 g of butyl acetate, and hexane was added dropwise in small amounts to the resulting solution while stirring it. The titration amount at the time when the solution started to become cloudy was determined, and the turbidity point titration was calculated by the following formula (iii). Turbid point titration=0.5×I×56.1 / (J×K)···(iii) In the following formula (iii), I represents the titer (mL) determined above, J represents the weighed sample mass (g), and K represents the hydroxyl value (mg-KOH / g) of the polycarbonate diol composition.

[0185] [Physical Property 6] Acid value The acid value of the polycarbonate diol compositions obtained in the examples and comparative examples described below was determined by a method according to JIS K 0070-1992, except that the solvent was changed to toluene / ethanol (2 / 1).

[0186] [Physical Property 7] Structural unit (I) content in polycarbonate diol composition 1 g of a sample of the polycarbonate diol composition obtained in the examples and comparative examples described below was taken in a 100 mL eggplant flask, 30 g of methanol, and 8 g of 28% sodium methoxide methanol solution were added, and the mixture was reacted at 100°C for 1 hour. After cooling the reaction liquid to room temperature, 2 to 3 drops of phenolphthalein were added as an indicator, and the mixture was neutralized with hydrochloric acid. After cooling in a refrigerator for 1 hour, the mixture was filtered through a filter and analyzed using gas chromatography (GC). The GC analysis was performed using a gas chromatograph GC-14B (Shimadzu Corporation, Japan) equipped with DB-WAX (J&W, USA) as a column, diethylene glycol diethyl ester was used as an internal standard, and a hydrogen flame ionization detector (FID) was used as a detector, and quantitative analysis of each component was performed. The temperature rise profile of the column was held at 60°C for 5 minutes, and then raised to 250°C at 10°C / min. The composition of the polycarbonate diol composition was determined from the alcohol components and the methyl ester components derived from the dibasic acid detected from the above analysis results. When no methyl ester components derived from dibasic acids were detected, the number of moles of diols constituting the carbonate skeleton was determined for the composition of the polyester polycarbonate polyol containing a dibasic acid by subtracting the same number of moles of diol from the number of moles of methyl ester derived from the dibasic acid (when multiple diols were used, the calculation was performed assuming that the composition of the diol in the carbonate skeleton and the composition of the diol in the ester skeleton were the same based on the ratio of diols determined by gas chromatography).

[0187] [Physical Property 8] Peroxide Value (POV) The polycarbonate diol composition samples obtained in the examples and comparative examples described below were immersed in the test part of a POV test paper (Shibata Scientific Co., Ltd.), left for 3 minutes, and washed with pure water. The POV test paper of the sample was compared with a standard color sample, and the peroxide value (POV) of the sample was determined as follows. [Judgment criteria] If it is detected as 0 on the standard color sample, it is marked as 0 meq / kg or more and 3 meq / kg or less. Over 3 meq / kg and up to 10 meq / kg, equivalent to the standard color sample of 10, is rated △. Anything over 10 meq / kg and up to 40 meq / kg, equivalent to the standard color sample of 30, is marked as "X".

[0188] [Physical Properties 9] Quality stability The polycarbonate diol compositions obtained in the Examples and Comparative Examples described later were stored at 25°C for 6 months, and the quality stability was evaluated based on the change in appearance from immediately after production as follows. [Evaluation Criteria] ○: No change in appearance immediately after manufacture ×: There is a change in appearance compared to immediately after production (e.g., separation into two layers, cloudiness, precipitation, etc.)

[0189] [Evaluation 1] Compatibility evaluation (polyol) The compatibility of the polycarbonate diol compositions obtained in the examples and comparative examples described later was evaluated as follows. As an example of polyol, polyester polyol (manufactured by Showa Denko Materials Co., Ltd., "Teslac 2460" (product name), number average molecular weight: about 2000) was used. The polyester polyol and the polycarbonate diol composition were mixed and stirred in a mass ratio of 7:3, and the compatibility was evaluated from the appearance of the obtained solution as follows. [Evaluation Criteria] 〇: Transparent △: Slightly cloudy or slightly separated into two layers ×: Cloudy

[0190] [Evaluation 2] Compatibility evaluation (solvent) The compatibility of the polycarbonate diol compositions obtained in the examples and comparative examples described later was evaluated as follows. As an example of a solvent, methyl isobutyl ketone (hereinafter, also referred to as "MIBK") was used. The polycarbonate diol composition was mixed with methyl isobutyl ketone so that the solid content was 75%, mixed and stirred at 25°C, and left to stand for 30 minutes. The compatibility was evaluated from the appearance of the obtained solution as follows. [Evaluation Criteria] 〇: Transparent △: Slightly cloudy ×: Cloudy

[0191] [Evaluation 3] Room temperature tensile test In accordance with JIS K6250 (2019), rectangular test pieces measuring 10 mm in width, 100 mm in length, and approximately 0.1 mm in thickness were prepared from the polyurethane films obtained in the application examples and application comparison examples described below. A tensile test was performed on the prepared test pieces using a tensile tester (manufactured by Orientec Co., Ltd., product name "Tensilon, Model RTE-1210") at a chuck distance of 20 mm, a tensile speed of 100 mm / min, and a temperature of 23°C (relative humidity of 55%), and the stress (100% modulus) at the point when the test piece was 100% elongated was measured. The lower the 100% modulus, the better the flexibility at room temperature.

[0192] [Evaluation 4] Low temperature tensile test In accordance with JIS K6250 (2019), rectangular test pieces with a width of 10 mm, length of 100 mm, and thickness of approximately 0.1 mm were prepared from the polyurethane films obtained in the application examples and application comparison examples described below. The prepared test pieces were placed in a tensile tester (manufactured by Orientec Co., Ltd., product name "Tensilon, model RTE-1210" with a thermostatic bath (manufactured by Orientec Co., Ltd., "Model TLF-R3T-EW") with a chuck distance of 20 mm. Next, the test pieces were left to stand at -20 ° C for 5 minutes, and then a tensile test was performed on the test pieces at a tensile speed of 100 mm / min, and the stress (100% modulus) at the point when the test pieces were 100% elongated was measured. It was evaluated that the lower the 100% modulus, the better the flexibility at low temperatures.

[0193] [Evaluation 5] ΔStress at 100% elongation (hereinafter sometimes referred to as "ΔM") From the 100% modulus (stress at 100% elongation) obtained in the above [Evaluation 1] and [Evaluation 2], ΔM was calculated according to the following formula (B). ΔM = M1 - M2 (B) (In formula (B), M1 is the stress at 100% elongation at -20°C as determined in [Evaluation 2], and M2 is the stress at 100% elongation at 23°C as determined in [Evaluation 1].)

[0194] [Evaluation 6] Evaluation of moisture and heat resistance A rectangular sample having a width of 10 mm, a length of 100 mm, and a thickness of about 100 μm was prepared from the polyurethane film obtained in the application examples and application comparison examples described below. The prepared sample was heated for 10 days at a temperature of 85° C. and a humidity of 85% in a thermohygrostat manufactured by Espec Corporation, product name "PL-1J". The breaking strength of the heated sample was measured in the same manner as in the above <room temperature tensile test>, and the breaking strength retention rate (%) was calculated from the following formula (C). Retention rate = breaking strength after heating / breaking strength before heating × 100 (C)

[0195] [Evaluation 7] ΔAPHA of polyurethane solution The polyurethane solutions obtained in the application examples and application comparison examples described below were stored in a small environmental testing machine at 40°C, and the change over time (ΔAPHA (after 3 months of storage - immediately after preparation)) of the APHA immediately after preparation of the polyurethane solution and the APHA of the polyurethane solution after storage at 40°C for 3 months was measured.

[0196] The abbreviations used in the tables and text are as follows: A-1: Polyoxytetramethylene glycol (manufactured by Mitsubishi Chemical Corporation, "PTMG2000" (trade name), number average molecular weight: about 2000, in general formula (II-1), R 211 : tetramethylene group, n211: approx. 28) A-2: Polyoxytetramethylene glycol (manufactured by Mitsubishi Chemical Corporation, "PTMG1000" (trade name), number average molecular weight: about 1000, in general formula (II-1), R 211 : tetramethylene group, n211: approx. 14) A-3: Polyoxyethylene polyoxypropylene glycol (manufactured by Sanyo Chemical Industries, Ltd., "Newpol PE-61" (trade name), number average molecular weight: about 2000, in general formula (II-1), R 211 : isopropylene group and methylene group, n211: about 35) A-4: Polyoxyethylene polyoxypropylene glycol (manufactured by Sanyo Chemical Industries, Ltd., "Newpol PE-62" (trade name), number average molecular weight: about 2400, in general formula (II-1), R 211 : isopropylene and methylene groups, n211: approx. 44) A-5: Copolymer of tetrahydrofuran and neopentyl glycol (manufactured by Asahi Kasei Corporation, "PTXG" (trade name), number average molecular weight: about 1800, in general formula (II-1), R 211 : 2,2-dimethyltrimethylene group and tetramethylene group, n211: about 23) B-1: Polycaprolactone polyol (manufactured by Daicel Organic Synthesis Company, Ltd., "Placcel 220" (trade name), number average molecular weight: about 2000, in general formula (III-1), R 311 : Pentamethylene group, n311: approx. 18) B-2: polyester polyol (manufactured by DIC Corporation, "OD-X-2692" (trade name), number average molecular weight: about 2000, in general formula (IV-1), R 411 : Tetramethylene group, R 421 : isobutylene group, n411: approx. 10) B-3: Polyester polyol (manufactured by Kuraray Co., Ltd., "P-2020" (trade name), number average molecular weight: about 2000, in general formula (IV-1), R 411 : Phenylene group, R 421 : 3-methylpentamethylene group, n411: approx. 8)

[0197] [Synthesis Example 1] Production of polycarbonate diol P-1 230g of 1,5-pentanediol, 250g of 1,6-hexanediol, and 400g of ethylene carbonate were charged into a 1L glass flask (hereinafter also referred to as "reactor") equipped with a rectification column filled with structured packing and a stirrer, and then 0.0468g of titanium tetra-n-butoxide was added as a catalyst. The reactor was immersed in an oil bath at 180°C, and the reaction was carried out at a reaction temperature of 165°C for 12 hours while extracting a part of the distillate. Next, the reactor was directly connected to a condenser, and the temperature of the oil bath was raised to 180°C, and the pressure was gradually lowered and the reaction was carried out for another 3 hours to obtain polycarbonate diol P-1 (466g), which is liquid at room temperature. The hydroxyl value of the obtained polycarbonate diol P-1 was 55.2mg-KOH / g. The number average molecular weight of the obtained polycarbonate diol P-1 was 2033.

[0198] [Synthesis Example 2] Production of polycarbonate diol P-2 270g of 1,6-hexanediol, 250g of 1,4-butanediol, and 445g of ethylene carbonate were charged into a 1L glass flask (hereinafter also referred to as "reactor") equipped with a rectification column filled with structured packing and a stirrer, and then 0.0960g of titanium tetra-n-butoxide was added as a catalyst. The reactor was immersed in an oil bath at 140 to 160°C, and the reaction was carried out for 20 hours at a reaction temperature of 90 to 160°C while extracting a part of the distillate. Next, the reactor was directly connected to a condenser, and the temperature of the oil bath was raised to 180°C, and the pressure was gradually lowered and the reaction was carried out for another 8 hours to obtain polycarbonate diol P-2 (462g), which is liquid at room temperature. The hydroxyl value of the obtained polycarbonate diol P-2 was 56.1mg-KOH / g. The number average molecular weight of the obtained polycarbonate diol P-2 was 2,000.

[0199] [Synthesis Example 3] Production of polycarbonate diol P-3 230g of 1,5-pentanediol, 250g of 1,6-hexanediol, and 400g of ethylene carbonate were charged into a 1L glass flask (hereinafter also referred to as "reactor") equipped with a rectification column filled with structured packing and a stirrer, and then 0.0468g of titanium tetra-n-butoxide was added as a catalyst. The reactor was immersed in an oil bath at 180°C, and the reaction was carried out at a reaction temperature of 165°C for 12 hours while extracting a part of the distillate. Next, the reactor was directly connected to a condenser, and the temperature of the oil bath was raised to 165°C, and the reaction was carried out for another 3 hours with the pressure gradually reduced, to obtain polycarbonate diol P-3 (478g) which is liquid at room temperature. The hydroxyl value of the obtained polycarbonate diol P-3 was 112.0mg-KOH / g. The number average molecular weight of the obtained polycarbonate diol P-3 was 1002.

[0200] [Example 1] Preparation of polycarbonate diol composition SA-1 In a 1L glass flask (hereinafter also referred to as "reactor") equipped with a stirrer, 90 parts by mass (360 g) of the polycarbonate diol P-2 obtained in Synthesis Example 2 and 10 parts by mass (40 g) of polyoxytetramethylene glycol (manufactured by Mitsubishi Chemical Corporation, "PTMG2000" (trade name), number average molecular weight: about 2000) were charged. Next, in the reactor, the pressure was reduced to 0.1 kPa.s or less using a vacuum pump and the mixture was stirred at 120°C for 10 minutes, after which nitrogen replacement was performed and it was confirmed that the oxygen concentration was 0.5% or less. While maintaining a nitrogen flow rate of 1 L / min, the temperature in the reactor was heated and stirred at about 145°C for 12 hours. The reaction solution was subjected to turbidity point titration over time. When it was confirmed that the turbidity point titration amount did not change, dibutyl phosphate was added in an amount 1.3 times by mass relative to titanium tetra-n-butoxide, and the mixture was heated at a reactor temperature of 110°C for 3 hours to obtain polycarbonate diol composition SA-1. The properties of the obtained polycarbonate diol composition SA-1 were measured by the above-mentioned methods. The results are shown in Table 1. The hydroxyl value of the obtained polycarbonate diol composition SA-1 was 56.6 mg-KOH / g. The number average molecular weight of the obtained polycarbonate diol composition SA-1 was 1982. The obtained polycarbonate diol composition SA-1 contained a repeating structural unit represented by the following formula (A1) and a repeating structural unit represented by the following formula (B1). [ka] (A2) (In general formula (A1), R 11 is an aliphatic hydrocarbon group having 4 or 6 carbon atoms. [ka] (B1) (In general formula (B1), R 21 is a tetramethylene group, and the average value of n21 is about 28.

[0201] [Examples 2 to 13] The reaction was carried out under the same conditions and in the same manner as in Example 1, except that the type and amount of each raw material was changed as shown in Tables 1 and 2, to obtain polycarbonate diol compositions SA-2 to SA-13 of Examples 2 to 13. The periodic quantitative determination and each physical property of the obtained polycarbonate diol compositions SA-2 to SA-13 during the turbidity point titration were measured by the above-mentioned methods. The results are shown in Tables 1 and 2. The obtained polycarbonate diol compositions SA-2 to SA-13 contained repeating structural units represented by the following formulae (A2) to (A13) and repeating structural units represented by the following formulae (B2) to (B13), respectively. [ka] (A2) (In general formula (A2), R 11 is an aliphatic hydrocarbon group having 5 or 6 carbon atoms. [ka] (B2) (In general formula (B2), R 21 is a tetramethylene group, and the average value of n21 is about 28. [ka] (A3) (In general formula (A3), R 11 is an aliphatic hydrocarbon group having 4 or 6 carbon atoms. [ka] (B3) (In general formula (B3), R 21 are isopropylene and methylene groups, and the average value of n21 is about 35. [ka] (A4) (In general formula (A4), R 11 is an aliphatic hydrocarbon group having 5 or 6 carbon atoms. [ka] (B4) (In general formula (B4), R 21 is a tetramethylene group, and the average value of n21 is about 28. [ka] (A5) (In general formula (A5), R 11 is an aliphatic hydrocarbon group having 5 or 6 carbon atoms. [ka] (B5) (In general formula (B5), R 21 are 2,2-dimethyltrimethylene and tetramethylene groups, and the average value of n21 is about 23. [ka] (A6) (In general formula (A6), R 11 is an aliphatic hydrocarbon group having 5 or 6 carbon atoms. [ka] (B6) (In general formula (B6), R 21 are 2,2-dimethyltrimethylene and tetramethylene groups, and the average value of n21 is about 23. [ka] (A7) (In general formula (A7), R 11 is an aliphatic hydrocarbon group having 5 or 6 carbon atoms. [ka] (B7) (In general formula (B7), R 21 is a tetramethylene group, and the average value of n21 is about 14. [ka] (A8) (In general formula (A8), R 11 is an aliphatic hydrocarbon group having 5 or 6 carbon atoms. [ka] (B8) (In general formula (B8), R 21 isopropylene and methylene groups, and the average value of n21 is about 44. [ka] (A9) (In general formula (A9), R 11 is an aliphatic hydrocarbon group having 5 or 6 carbon atoms. [ka] (B9) (In general formula (B9), R 21 is an isopropylene group and a methylene group, and the average value of n21 is about 35. [ka] (A10) (In general formula (A10), R 11 is an aliphatic hydrocarbon group having 4 or 6 carbon atoms. [ka] (B10) (In general formula (B10), R 31 is a pentamethylene group. [ka] (A11) (In general formula (A11), R 11 is an aliphatic hydrocarbon group having 5 or 6 carbon atoms. [ka] (B11) (In general formula (B11), R 41 is a tetramethylene group, and R 42 is an isobutylene group. [ka] (A12) (In general formula (A12), R 11 is an aliphatic hydrocarbon group having 5 or 6 carbon atoms. [ka] (B12) (In general formula (B12), R 41 is a phenylene group, R 42 is a 3-methylpentamethylene group. [ka] (A13) (In general formula (A3), R 11 is an aliphatic hydrocarbon group having 4 or 6 carbon atoms. [ka] (B13) (In general formula (B3), R 21 are isopropylene and methylene groups, and the average value of n21 is about 35.

[0202] [Comparative Example 1] Preparation of polycarbonate diol composition SB-1 In a 1L glass flask (hereinafter also referred to as "reactor") equipped with a stirrer, 25 parts by mass (100g) of the polycarbonate diol P-1 obtained in Synthesis Example 1 and 75 parts by mass (300g) of polyoxytetramethylene glycol (manufactured by Mitsubishi Chemical Corporation, "PTMG2000" (trade name), number average molecular weight: about 2000) were charged. Under an air atmosphere, the temperature inside the reactor was heated to about 145°C and maintained for 10 hours with stirring. Next, dibutyl phosphate was added in an amount 1.3 times the mass of titanium tetra-n-butoxide, and the mixture was heated at a reactor temperature of 110°C for 3 hours to obtain a polycarbonate diol composition SB-1. The physical properties of the obtained polycarbonate diol composition SB-1 were measured by the above-mentioned methods. The results are shown in Table 3. The resulting polycarbonate diol composition SB-1 had a hydroxyl value of 56.2 mg-KOH / g and a number average molecular weight of 1,996.

[0203] [Comparative Example 2] Preparation of polycarbonate diol composition SB-2 The reaction was carried out under the same conditions and in the same manner as in Comparative Example 1, except that the type and amount of each raw material was changed as shown in Table 2, to obtain a polycarbonate diol composition SB-2 of Comparative Example 2. The physical properties of the obtained polycarbonate diol composition SB-2 were measured by the above-mentioned methods. The results are shown in Table 3.

[0204] [Comparative Example 3] Preparation of polycarbonate diol composition SB-3 In a 1L glass flask (hereinafter also referred to as "reactor") equipped with a stirrer, 400 g of the polycarbonate diol P-2 obtained in Synthesis Example 2 and dibutyl phosphate were added in an amount 1.3 times the mass of titanium tetra-n-butoxide, and the mixture was heated at a reactor temperature of 110°C for 3 hours to obtain a polycarbonate diol composition SB-3. The properties of the obtained polycarbonate diol composition SB-3 were measured by the above-mentioned methods. The results are shown in Table 3. The hydroxyl value of the obtained polycarbonate diol composition SB-3 was 56.1 mg-KOH / g and the number average molecular weight was 2000.

[0205] [Comparative Example 4] Preparation of polycarbonate diol composition SB-4 In a 1L glass flask equipped with a stirrer (hereinafter also referred to as "reactor"), 90 parts by mass (360 g) of the polycarbonate diol P-2 obtained in Synthesis Example 2 and 10 parts by mass (40 g) of polyoxytetramethylene glycol (manufactured by Mitsubishi Chemical Corporation, "PTMG2000" (trade name), number average molecular weight: about 2000) were charged. Next, in the reactor, the pressure was reduced to 0.1 kPa.s or less using a vacuum pump, and the mixture was stirred at 120°C for 10 minutes, after which nitrogen replacement was performed to confirm that the oxygen concentration was 0.5% or less. While maintaining a nitrogen flow rate of 1 L / min, the temperature in the reactor was heated and stirred at about 145°C for 6 hours. GPC measurement was performed over time on the reaction solution to confirm the disappearance of the peaks derived from the raw materials and the appearance of the peaks derived from the product over time, and the progress of the reaction was confirmed. Thereafter, dibutyl phosphate was added in an amount 1.3 times the mass of titanium tetra-n-butoxide, and the mixture was heated at 110°C in the reactor for 3 hours to obtain polycarbonate diol composition SB-4. The properties of the obtained polycarbonate diol composition SB-4 were measured by the above-mentioned methods. The results are shown in Table 3. The hydroxyl value of the obtained polycarbonate diol composition SB-4 was 56.2 mg-KOH / g. The number average molecular weight of the obtained polycarbonate diol composition SB-4 was 1996.

[0206] [Table 1]

[0207] [Table 2]

[0208] [Table 3]

[0209] [Application Example 1] Synthesis of polyurethane film PA-1 In a 500 mL separable flask equipped with a thermocouple and a cooling tube, 38 g of the polycarbonate diol composition SA-1, 224 g of dimethylformamide (hereinafter sometimes abbreviated as DMF), and 0.26 g of a 1% dibutyltin dilaurate toluene solution (50 ppm relative to the total mass of MDI and the polycarbonate diol composition) were placed and heated in an oil bath at 40°C. While stirring the solution in the flask at 100 rpm under a nitrogen atmosphere in the flask, 14.8 g of MDI (3.09 times [mol] relative to the OH [mol] of the polycarbonate diol composition) was dropped, and the solution in the flask was further stirred for about 1.5 hours. The isocyanate group concentration was analyzed, and it was confirmed that the theoretical amount had been consumed, and a prepolymer was obtained. Next, 3.2 g of 1,4-butanediol (1,4-BD), the required amount calculated from the remaining isocyanate, was added in portions to the flask. After stirring the solution in the flask for about 1 hour, about 1 g of ethanol was added, and the solution in the flask was further stirred for 30 minutes to obtain a polyurethane solution having a number average molecular weight of 74,000. Using a 0.8 mm thick applicator, the obtained polyurethane solution was dropped onto the top of a glass plate (JIS R3202, 2 mm x 100 mm x 150 mm) to coat the plate so that the dry film thickness was 50 to 150 μm, and the plate was dried for 2 hours on a hot plate with a surface temperature of 60 ° C, and then for 12 hours in an oven at 80 ° C. The plate was then left to stand for 12 hours or more at a constant temperature and humidity of 23 ° C and 55% RH to obtain a polyurethane film PA-1. The obtained polyurethane film PA-1 was subjected to evaluation of various physical properties by the above-mentioned methods. The evaluation results are shown in Table 4.

[0210] [Application Examples 2-13] In the production of the polyurethane film of Application Example 1, the reaction was carried out under the same conditions as in Application Example 1, except that the polycarbonate diol compositions used were changed to the polycarbonate diol compositions SA-2 to SA-13 produced in Examples 2 to 12, to obtain polyurethane films PA-2 to PA-13. The obtained polyurethane films PA-2 to PA-13 were subjected to evaluation of various physical properties by the above-mentioned methods. The evaluation results are shown in Tables 4 and 5.

[0211] [Application comparison examples 1-4] In the production of the polyurethane film of Application Example 1, the reaction was carried out under the same conditions as in Application Example 1, except that the polycarbonate diol compositions used were changed to the polycarbonate diol compositions SB-1 to SB-4 produced in Comparative Examples 1 to 3, to obtain polyurethane films PB-1 to PB-4. The obtained polyurethane films PB-1 to PB-4 were subjected to evaluation of various physical properties by the above-mentioned methods. The evaluation results are shown in Table 6.

[0212] [Table 4]

[0213] [Table 5]

[0214] [Table 6]

[0215] From the results shown in Tables 1 to 3, it was found that a polycarbonate diol composition containing the repeating structural unit (I) and further containing at least one repeating structural unit selected from the group consisting of the repeating structural units (II) to (IV) and satisfying certain conditions has better compatibility with polyols and solvents than a polycarbonate diol composition not satisfying the certain conditions. It was also found that by controlling the acid value and / or peroxide value of the polycarbonate diol composition, the APHA can be further reduced and coloration can be further reduced.

[0216] In addition, from the results shown in Tables 4 to 6, it was found that the polyurethane obtained from the polycarbonate diol composition of the Examples has excellent flexibility and mechanical properties at low temperatures, and is also excellent in balance with durability such as resistance to moist heat, etc. In addition, it was confirmed that the change over time of APHA of the polyurethane solution obtained from the polycarbonate diol composition of the Examples was also good.

[0217] This application is based on a Japanese patent application (Patent Application No. 2021-072116) filed on April 21, 2021, the contents of which are incorporated herein by reference. [Industrial Applicability]

[0218] The polycarbonate diol composition of the present embodiment can be highly solidified during the production of paints and polyurethanes, and is useful as a raw material for paints and polycarbonate-based polyurethanes. The polyurethanes produced using the polycarbonate diol composition of the present embodiment have stable color tone, excellent low-temperature flexibility, and excellent durability, and can be suitably used in a wide range of fields, such as elastic fibers, synthetic or artificial leathers, paints, and high-performance elastomers.

Claims

1. A polycarbonate diol composition comprising a repeating structural unit represented by the following general formula (I), and further comprising at least one repeating structural unit selected from the group consisting of a repeating structural unit represented by the following general formula (II), a repeating structural unit represented by the following general formula (III), and a repeating structural unit represented by the following general formula (IV), and satisfying the following formula (Formula 1): 【Chemistry 1】 (In general formula (I), R 11 R is a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 15 carbon atoms, or an aromatic hydrocarbon group. 11 may be the same or different.) 【Chemistry 2】 (In general formula (II), R 21 R is a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 21 may be the same or different. n21 is any integer.) 【Chemistry 3】 (In general formula (III), R 31 R is a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 31 may be the same or different.) 【Chemistry 4】 (In general formula (IV), R 41 and R 42 are each independently a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 41 and R 42 may be the same or different.) ｽ≧3.7×α (α=22.4×Mn -0.41 ) …………(Formula 1) (In formula 1, x is the ratio of the content (mass%) of the repeating structural unit represented by the general formula (I) to the total mass (mass%) of the repeating structural units represented by the general formulas (I) to (IV), y is the titration amount (mL) of the polycarbonate diol composition by the turbidity point titration method, and Mn is the number average molecular weight of the polycarbonate diol composition.)

2. A polycarbonate diol composition comprising a repeating structural unit represented by the following general formula (I), and further comprising at least one repeating structural unit selected from the group consisting of a repeating structural unit represented by the following general formula (II), a repeating structural unit represented by the following general formula (III), and a repeating structural unit represented by the following general formula (IV), wherein the content of the repeating structural unit represented by the general formula (I) is 40 mass% or more based on the total mass of the repeating structural units represented by the general formulas (I) to (IV), and the titration amount measured by a turbidity point titration method is 4.0 mL or more and 9.5 mL or less. 【Chemistry 5】 (In general formula (I), R 11 R is a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 15 carbon atoms, or an aromatic hydrocarbon group. 11 may be the same or different.) 【Chemistry 6】 (In general formula (II), R 21 R is a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 21 may be the same or different. n21 is any integer.) 【Chemistry 7】 (In general formula (III), R 31 R is a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 31 may be the same or different.) 【Chemistry 8】 (In general formula (IV), R 41 and R 42 are each independently a divalent linear, branched or cyclic aliphatic hydrocarbon group having from 2 to 20 carbon atoms, or an aromatic hydrocarbon group. 41 and R 42 may be the same or different.)

3. The polycarbonate diol composition according to claim 1, wherein the content of the repeating structural unit represented by the general formula (I) is 5 mass% or more and 95 mass% or less based on the total mass of the repeating structural units represented by the general formulas (I) to (IV).

4. The polycarbonate diol composition according to claim 1 or 2, wherein the content of the repeating structural unit represented by the general formula (I) is 40 mass% or more and 90 mass% or less, based on the total mass of the repeating structural units represented by the general formulas (I) to (IV).

5. The polycarbonate diol composition according to claim 1 or 2, having an acid value of 0.001 mg-KOH / g or more and 0.8 mg-KOH / g or less.

6. The polycarbonate diol composition according to claim 1 or 2, having a peroxide content of 10 meq / kg or less.

7. The polycarbonate diol composition according to claim 1 or 2, wherein, among the repeating structural units represented by general formulas (II) to (IV), the average repeat number n21 of the repeating structural unit represented by general formula (II) is 15 or more.

8. The polycarbonate diol composition according to claim 1 or 2, which contains at least a repeating structural unit represented by general formula (II) or (IV) among the repeating structural units represented by general formulas (II) to (IV).

9. The polycarbonate diol composition according to claim 1 or 2, which contains at least a repeating structural unit represented by general formula (II) among the repeating structural units represented by general formulas (II) to (IV).

10. A polyurethane obtained by using the polycarbonate diol composition according to claim 1 or 2.

11. The polyurethane according to claim 10 , wherein a stress at 100% elongation in a tensile test of the polyurethane, calculated by the following formula (B), is 1.0 or more and 19.0 or less: ΔM=M1-M2...(B) (In formula (B), M1 represents the stress at 100% elongation in a tensile test at −20° C., and M2 represents the stress at 100% elongation in a tensile test at 23° C.)

12. 11. Synthetic leather comprising the polyurethane of claim 10.

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