Polycarbonate diol composition and polyurethane

Abstract

Disclosed is a polycarbonate diol composition which contains a polycarbonate diol that comprises a structural unit (1) represented by general formula (I), and a nitrogen-containing compound, wherein the content of the nitrogen-containing compound is 5,000 mass ppm or less in terms of nitrogen atoms.　Even in cases where a polycarbonate diol composition is obtained using a diol that includes 1,4-butanediol as a starting material, the formation of tetrahydrofuran during heating is suppressed. By using this polycarbonate diol composition, it is possible to obtain a polyurethane that has excellent transparency and excellent mechanical characteristics such as strength at break, elongation at break, and elastic modulus.

Description

Polycarbonate diol composition and polyurethane

[0001] The present invention relates to a polycarbonate diol composition. Furthermore, the present invention relates to a polyurethane obtained using the polycarbonate diol composition.

[0002] Polycarbonate-type polyurethanes, which use polycarbonate diol as a raw material for the soft segment portion, have been proposed as polyurethanes produced on an industrial scale (Non-Patent Document 1). Polycarbonate-type polyurethanes have excellent heat resistance and hydrolysis resistance, and are therefore widely used in applications such as (water-based) paints, adhesives, and durable films for construction materials such as artificial leather for automobiles and furniture, and clothing. These applications require polyurethanes with excellent mechanical properties and excellent transparency without coloration.

[0003] To solve these problems, polycarbonate diols containing structural units derived from 1,4-butanediol have been proposed. For example, Patent Document 1 discloses a polycarbonate diol containing structural units derived from 1,4-butanediol and structural units derived from 1,5-pentanediol, and a method for producing the same. Furthermore, Patent Document 2 proposes a polycarbonate diol containing structural units derived from 1,4-butanediol and structural units derived from 1,6-hexanediol, and a method for producing the same.

[0004] Japanese Patent Application Laid-Open No. 4-7327 International Publication No. 2009 / 63767

[0005] "Fundamentals and Applications of Polyurethanes" pp. 96-106, edited by Katsuji Matsunaga, CMC Publishing Co., Ltd., published November 2006

[0006] However, according to studies by the present inventors, when the polycarbonate diol compositions obtained by the methods described in Patent Documents 1 and 2 are heated, for example, during the polyurethane polymerization process, the structural units derived from 1,4-butanediol in the polycarbonate diol are depolymerized to generate 1,4-butanediol, which then undergoes a cyclization reaction to produce tetrahydrofuran. It has also been found that the structural units derived from 1,4-butanediol at the terminals of the polycarbonate diol undergo a cyclization reaction accompanied by decarboxylation to produce tetrahydrofuran. When producing polyurethane using such a polycarbonate diol composition containing tetrahydrofuran, or when processing the resulting polyurethane into a film, fiber, or other molded article, silver streaks and foaming occur due to the evaporation of tetrahydrofuran, impairing the appearance of the polyurethane product. Furthermore, the polycarbonate diol compositions obtained by the methods described in Patent Documents 1 and 2 have insufficient mechanical properties and transparency.

[0007] The present invention has been made in view of the above-mentioned problems. That is, an object of the present invention is to provide a polycarbonate diol composition obtained from a diol containing 1,4-butanediol as a raw material, which suppresses the generation of tetrahydrofuran when heated, and which makes it possible to obtain a polyurethane having excellent mechanical properties such as strength at break, elongation at break, and modulus of elasticity, as well as transparency. Another object of the present invention is to provide a method for producing a polycarbonate diol composition which suppresses the generation of tetrahydrofuran when heated, and which makes it possible to obtain a polyurethane having excellent mechanical properties such as strength at break, elongation at break, and modulus of elasticity, as well as transparency, using the polycarbonate diol.

[0008] As a result of extensive research into solving the above problems, the present inventors have found that the above problems can be solved by adding a nitrogen-containing compound such as an amine to a polycarbonate diol composition.

[0009] That is, the gist of the present invention is as follows: [1] A polycarbonate diol composition containing a polycarbonate diol containing a structural unit (1) represented by the following general formula (I) and a nitrogen-containing compound, wherein the content of the nitrogen-containing compound is 5000 mass ppm or less in terms of nitrogen atoms. [2] The polycarbonate diol composition according to [1] above, wherein the content of the nitrogen-containing compound is 0.1 ppm by mass or more in terms of nitrogen atoms. [3] The polycarbonate diol composition according to [1] or [2] above, wherein the content of the nitrogen-containing compound is 50 ppm by mass or less in terms of nitrogen atoms. [4] The polycarbonate diol composition according to any one of [1] to [3] above, further comprising a phosphorus atom-containing compound, wherein the content of the phosphorus atom-containing compound is 50 ppm by mass or less in terms of phosphorus atoms. [5] The polycarbonate diol composition according to any one of [1] to [4] above, wherein the nitrogen-containing compound is an amine compound. [6] The polycarbonate diol composition according to any one of [1] to [5] above, wherein the nitrogen-containing compound contains one amino group and one or more functional groups, the functional group comprising at least one selected from the group consisting of a hydroxyl group, a carboxyl group, a formyl group, and an amino group. [7] The polycarbonate diol composition according to any one of the above [1] to [6], wherein the nitrogen-containing compound contains an amine represented by the following general formula (II-1): (In the above general formula (II-1), R １ represents an alkylene group having 2 to 20 carbon atoms and r substituents X, which may have substituents other than X. X represents a hydroxyl group, a carboxyl group, a formyl group, or an amino group. r is an integer of 1 to 6. R ２ and R ３each independently represents an alkyl group having 1 to 20 carbon atoms, which may have a substituent, or a hydrogen atom.) [8] The polycarbonate diol composition according to any one of [1] to [7] above, wherein the number average molecular weight (Mn) of the polycarbonate diol is 250 or more and 5,000 or less. [9] A polyurethane made from the polycarbonate diol composition according to any one of [1] to [8] above and an isocyanate compound.

[10] The polyurethane according to [9] above, which is used for any one selected from the group consisting of active-energy radiation-curable polymer compositions, artificial leather, synthetic leather, paints, coating agents, elastic fibers, pressure-sensitive adhesives, and adhesives.

[0010] According to the present invention, there can be provided a polycarbonate diol composition obtained from a diol containing 1,4-butanediol as a raw material, which suppresses the generation of tetrahydrofuran during heating, and which makes it possible to obtain a polyurethane using the polycarbonate diol composition that is excellent in mechanical properties such as strength at break, elongation at break, and elastic modulus, as well as transparency.

[0011] 1 is a graph showing the relationship between the nitrogen atom-equivalent content of a nitrogen-containing compound in a polycarbonate diol composition and the amount of tetrahydrofuran (THF) produced in the polycarbonate diol composition after heat treatment for Examples 1 to 7 and 31. 2 is a graph showing the relationship between the nitrogen atom-equivalent content of a nitrogen-containing compound (trihexylamine) in a polycarbonate diol composition and the amount of tetrahydrofuran (THF) produced in the polycarbonate diol composition after heat treatment for Examples 8 to 10 and Comparative Example 2. 3 is a graph showing the relationship between the nitrogen atom-equivalent content of a nitrogen-containing compound (trihexylamine) in a polycarbonate diol composition and the amount of tetrahydrofuran (THF) produced in the polycarbonate diol composition after heat treatment for Examples 11 to 13 and Comparative Example 3. 4 is a graph showing the relationship between the nitrogen atom-equivalent content of a nitrogen-containing compound (trihexylamine) in a polycarbonate diol composition and the breaking strength of the resulting polyurethane for Examples 14 to 17 and Comparative Example 4. 1 is a graph showing the relationship between the content of the nitrogen-containing compound (trihexylamine) in terms of nitrogen atoms contained in the polycarbonate diol composition and the breaking elongation of the resulting polyurethane for Examples 14 to 17 and Comparative Example 4. 2 is a graph showing the relationship between the content of the nitrogen-containing compound (trihexylamine) in terms of nitrogen atoms contained in the polycarbonate diol composition and the elastic modulus of the resulting polyurethane for Examples 14 to 17 and Comparative Example 4. 3 is a graph showing the relationship between the content of the nitrogen-containing compound (trihexylamine) in terms of nitrogen atoms contained in the polycarbonate diol composition and the transparency (YI value) of the resulting polyurethane for Examples 14 to 17 and Comparative Example 4. 4 is a graph showing the relationship between the content of the nitrogen-containing compound (trihexylamine) in terms of nitrogen atoms contained in the polycarbonate diol composition and the breaking strength of the resulting polyurethane for Examples 18 to 20 and Comparative Example 5. 1 is a graph showing the relationship between the content of a nitrogen-containing compound (trihexylamine) in a polycarbonate diol composition in terms of nitrogen atoms contained therein and the breaking elongation of the resulting polyurethane for Examples 18 to 20 and Comparative Example 5.1 is a graph showing the relationship between the content of a nitrogen-containing compound (trihexylamine) in a polycarbonate diol composition in terms of nitrogen atoms contained and the elastic modulus of the resulting polyurethane for Examples 18 to 20 and Comparative Example 5. 2 is a graph showing the relationship between the content of a nitrogen-containing compound (trihexylamine) in a polycarbonate diol composition in terms of nitrogen atoms contained and the transparency (YI value) of the resulting polyurethane for Examples 18 to 20 and Comparative Example 5.

[0012] The following describes in detail the embodiments of the present invention, but the present invention is not limited to the following embodiments and can be practiced in various modifications within the scope of the gist. Unless otherwise specified, in this specification, a numerical range expressed using "to" means a range including the numerical values ​​written before and after "to" as the lower and upper limits, and "A to B" means A or more and B or less.

[0013] In this specification, "A or B" means "A," "B," and "A and B," unless otherwise specified. For example, "including A or B" means "including A," "including B," and "including A and B," unless otherwise specified.

[0014] In this specification, "mass %" indicates the content ratio of a specified component contained in a total amount of 100 mass %. In this specification, "mass %" and "weight %", "mass ppm" and "weight ppm", and "parts by mass" and "parts by weight" are synonymous. Furthermore, when simply written as "ppm", it means "ppm by weight".

[0015] In this specification, the term "structural unit" refers to a unit derived from a raw material compound used in the production of a polycarbonate diol, formed by polymerization of the raw material compound, and refers to a partial structure sandwiched between any linking groups in the obtained polymer. It also includes a partial structure at the terminal portion of a polymer, one of which is a linking group and the other of which is a polymerization reactive group. The structural unit may be a unit formed directly by a polymerization reaction, or may be a unit obtained by converting a part of the unit into another structure by treating the obtained polymer. In this specification, the term "repeating unit" has the same meaning as "structural unit".

[0016] As used herein, the terms "any" or "optionally" mean that the subsequently described situation may or may not occur, and therefore the description includes both the occurrence and non-occurrence of the situation. Also, the term "about" as used herein can mean a range of 20% above and below the stated value. For example, about 75°C encompasses the range of 60°C to 90°C.

[0017] In this specification, "obtained polyurethane" refers to polyurethane produced using the polycarbonate diol composition of the present invention, more specifically, polyurethane produced using the polycarbonate diol composition of the present invention and an isocyanate compound as raw materials. In addition, in this specification, "the polycarbonate diol composition of the present invention" and "the polyurethane of the present invention" are collectively referred to as "the present invention."

[0018] All steps described herein can be performed in any suitable order unless otherwise stated herein or clearly contradicted by context.

[0019] Hereinafter, the embodiments of the present invention will be described in detail. However, the explanation of the constituent elements described below is an example of an embodiment of the present invention, and the present invention is not limited to these contents.

[0020] <Polycarbonate diol composition> The polycarbonate diol composition of the present invention is a polycarbonate diol composition containing a polycarbonate diol containing a structural unit (1) represented by the following general formula (I) (hereinafter, this may be referred to as the "polycarbonate diol of the present invention") and a nitrogen-containing compound. Details of the structural unit (1) will be described later.

[0021]

[0022] Furthermore, the content of the nitrogen-containing compound in the polycarbonate diol composition is 5000 mass ppm or less in terms of nitrogen atoms.

[0023] The polycarbonate diol composition of the present invention contains a nitrogen-containing compound, which can suppress the generation of tetrahydrofuran when the polycarbonate diol composition is heated. Furthermore, the polycarbonate diol composition of the present invention contains a nitrogen-containing compound, which can be used to stably produce polyurethane products that are excellent in mechanical properties such as strength at break, elongation at break, and modulus of elasticity, as well as transparency. Details of the nitrogen-containing compound will be described later.

[0024] Furthermore, by setting the content of the phosphorus-containing compound in the polycarbonate diol composition of the present invention to a threshold value or less, the effect of suppressing the generation of tetrahydrofuran when the polycarbonate diol composition is heated can be further improved. This makes it possible to stably produce high-quality polyurethane products with better product appearance, mechanical properties, etc., using the polycarbonate diol composition. Details of the phosphorus-containing compound will be described later.

[0025] <Polycarbonate diol> The polycarbonate diol in the present invention is a component constituting the polycarbonate diol composition of the present invention, and is a polycarbonate diol containing the structural unit (1) described below. By containing the structural unit (1), the polycarbonate diol in the present invention can maintain good mechanical properties and chemical resistance of the polyurethane obtained using the polycarbonate diol composition of the present invention.

[0026] Furthermore, the polycarbonate diol in the present invention may contain the structural unit (2) described below, as needed, within a range that does not impair the effects of the present invention.

[0027] (Molecular Weight of Polycarbonate Diol) The lower limit of the number average molecular weight (Mn) of the polycarbonate diol in the present invention is not particularly limited, and from the viewpoint of obtaining good mechanical properties of the resulting polyurethane, it is preferably 250 or more, more preferably 300 or more, and even more preferably 400 or more. On the other hand, the upper limit of the number average molecular weight (Mn) is not particularly limited, and from the viewpoint of appropriately suppressing the viscosity of the polycarbonate diol composition of the present invention and maintaining good handleability, and from the viewpoint of maintaining good chemical resistance of the resulting polyurethane, it is preferably 5000 or less, more preferably 4000 or less, and even more preferably 3000 or less. The above upper and lower limits can be arbitrarily combined. For example, the number average molecular weight (Mn) of the polycarbonate diol in the present invention is preferably 250 or more and 5000 or less, more preferably 300 or more and 4000 or less, and even more preferably 400 or more and 3000 or less. The number average molecular weight (Mn) is a molecular weight calculated using the hydroxyl value according to the following formula: Number average molecular weight (Mn) = 2 × 56.1 / (hydroxyl value × 10 －３ The hydroxyl value can be measured by a known method using an acetylating reagent in accordance with JIS K1557-1.

[0028] (Structural Unit (1)) The above-mentioned structural unit (1) is a structural unit represented by the following general formula (I) contained in the structure of the polycarbonate diol of the present invention.

[0029] When the polycarbonate diol contains the structural unit (1), the mechanical properties and chemical resistance of the polyurethane obtained using the polycarbonate diol composition of the present invention can be maintained at a good level.

[0030] The lower limit of the content of the structural unit (1) in the polycarbonate diol in the present invention is not particularly limited, but from the viewpoint of maintaining good mechanical properties and chemical resistance of the resulting polyurethane, it is preferably 20 mol% or more, more preferably 40 mol% or more, even more preferably 50 mol% or more, and particularly preferably 60 mol% or more, relative to 100 mol% of the structural units of the polycarbonate diol. On the other hand, the upper limit of the content of the structural unit (1) is not particularly limited, but from the viewpoint of maintaining good strength and durability of the resulting polyurethane, it may be 100 mol% relative to 100 mol% of the structural units of the polycarbonate diol, or preferably less than 100 mol%, more preferably 99 mol% or less, even more preferably 98 mol% or less, and particularly preferably 97 mol% or less. The above upper and lower limits can be combined arbitrarily. For example, the content of the structural unit (1) in the polycarbonate diol in the present invention is preferably 20 mol% or more and 100 mol% or less, more preferably 40 mol% or more and 99 mol% or less, still more preferably 50 mol% or more and 98 mol% or less, and particularly preferably 60 mol% or more and 97 mol% or less, relative to 100 mol% of the structural units of the polycarbonate diol.

[0031] In the polycarbonate diol of the present invention, the specific method for controlling the content ratio of the structural unit (1) within the above-mentioned numerical range is not particularly limited, and a person skilled in the art can control it by appropriately optimizing the production conditions of the polycarbonate diol of the present invention, which will be described later, based on well-known techniques.

[0032] In the polycarbonate diol of the present invention, the structural unit (1) represented by the formula (I) can be a compound represented by the following formula (I-1), that is, a structural unit derived from 1,4-butanediol.

[0033]

[0034] The polycarbonate diol of the present invention can achieve the Sustainable Development Goals (SDGs) by using biomass-derived 1,4-butanediol as the structural unit (1). Specifically, biomass-derived 1,4-butanediol alone or a mixture containing biomass-derived 1,4-butanediol and fossil fuel-derived 1,4-butanediol can be used. Biomass-derived 1,4-butanediol is 1,4-butanediol derived from non-edible biomass and / or non-fossil fuel.

[0035] When sugars or the like are used as biomass resources and fermented with bacteria to obtain 1,4-butanediol, the nitrogen-containing compounds may be produced as by-products. In the present invention, by using biomass-derived 1,4-butanediol as the 1,4-butanediol, the nitrogen-containing compounds produced as by-products can be effectively utilized, and in the obtained polycarbonate diol, it is possible to suppress the production of tetrahydrofuran when the polycarbonate diol composition is heated.

[0036] In the present invention, non-edible biomass refers to resources made from non-edible grasses or trees. Specific examples include, but are not limited to, cellulose, hemicellulose, lignin, etc. obtained from woody biomass such as coniferous and broad-leaved trees; bioethanol and biodiesel obtained from herbaceous biomass such as corn and sugarcane stalks, soybeans, and rapeseed; and plant-derived waste oil. In the present invention, non-fossil fuel refers to, for example, hydrogen or organic matter derived from animals and plants that is not derived from fossil fuels or non-edible biomass. Specific examples include, but are not limited to, methane and sugar ethanol obtained from firewood, charcoal, dried livestock manure, etc.

[0037] In the present invention, 1,4-butanediol derived from a fossil fuel refers to at least one selected from petroleum-derived 1,4-butanediol, coal-derived 1,4-butanediol, and natural gas-derived 1,4-butanediol.

[0038] (Structural Unit (2)) Furthermore, the polycarbonate diol composition of the present invention may contain, as necessary, a structural unit (2) derived from a hydroxy group-containing compound (2) within a range that does not impair the effects of the present invention. Specific examples of the hydroxy group-containing compound (2) include linear diols such as 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, and 1,20-eicosanediol; 1,3-butanediol, 2-methyl-1,3-propanediol, 2-methyl-1,4-butanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,6-hexanediol, 2-methyl-1,8-octanediol, and 2,2-dimethyl-1,6-hexanediol. diols having a side chain such as 2-butyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, and 2,2-dimethyl-1,3-propanediol; cyclic diols such as 1,4-cyclohexanedimethanol and 2-bis(4-hydroxycyclohexyl)propane; oxyalkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol; diols having a cyclic ether structure such as isosorbide, isomannide, and isoidet, which are stereoisomeric; and polyols having three or more hydroxyl groups per molecule such as trimethylolethane, trimethylolpropane, hexanetriol, and pentaerythritol. These compounds may be used alone or in combination of two or more.

[0039] The upper limit of the content of the structural unit (2) in the polycarbonate diol is not particularly limited, and from the viewpoint of maintaining good mechanical properties and chemical resistance of the obtained polyurethane without impairing the effects of the structural unit (1), it is preferably 80 mol% or less, more preferably 60 mol% or less, even more preferably 50 mol% or less, and particularly preferably 40 mol% or less, relative to 100 mol% of the structural units of the polycarbonate diol. On the other hand, the lower limit of the content of the structural unit (2) is not particularly limited, and usually may be 0 mol% or less, or preferably more than 0 mol%, more preferably 1 mol% or more, even more preferably 2 mol% or more, and particularly preferably 3 mol% or more, relative to 100 mol% of the structural units of the polycarbonate diol. The above upper and lower limits can be combined arbitrarily. For example, the content of the structural unit (2) in the polycarbonate diol in the present invention is preferably 0 mol% or more and 80 mol% or less, more preferably 1 mol% or more and 60 mol% or less, still more preferably 2 mol% or more and 50 mol% or less, and particularly preferably 3 mol% or more and 40 mol% or less, relative to 100 mol% of the structural units of the polycarbonate diol.

[0040] In the polycarbonate diol of the present invention, the specific method for controlling the content ratio of the structural unit (2) in the polycarbonate diol within the above-mentioned numerical range is not particularly limited, and a person skilled in the art can control it by appropriately optimizing the production conditions of the polycarbonate diol of the present invention, which will be described later, based on well-known techniques.

[0041] <Nitrogen-containing compound> The nitrogen-containing compound in the present invention is one of the constituent components of the polycarbonate diol composition in the present invention. The nitrogen-containing compound in the present invention is not particularly limited as long as it is a compound containing a nitrogen atom in the molecule, and a compound that can achieve the effects of the present invention can be appropriately selected and used from known nitrogen-containing compounds. For example, amine-based compounds and amide-based compounds can be mentioned, and amine-based compounds are preferred.

[0042] (First embodiment of nitrogen-containing compound) As a first embodiment, the nitrogen-containing compound contains one amino group and one or more functional groups, and the functional group can include at least one selected from the group consisting of a hydroxyl group, a carboxyl group, a formyl group, and an amino group. This can further improve the effect of suppressing the production of tetrahydrofuran when the polycarbonate diol composition is heated. Furthermore, the polycarbonate diol composition of the present invention can be used to provide polyurethane products with better mechanical properties such as breaking strength, breaking elongation, and elastic modulus, as well as transparency.

[0043] (Second Embodiment of Nitrogen-Containing Compound) As a second embodiment, the nitrogen-containing compound can contain an amine represented by the following general formula (II-1). This can further improve the effect of suppressing the production of tetrahydrofuran when the polycarbonate diol composition is heated. Furthermore, by using the polycarbonate diol composition of the present invention, the mechanical properties such as breaking strength, breaking elongation, and elastic modulus, as well as transparency, of the obtained polyurethane product can be made more excellent.

[0044]

[0045] In the above general formula (II-1), R １ represents an alkylene group having 2 to 20 carbon atoms and r substituents X, which may have substituents other than X. X represents a hydroxyl group, a carboxyl group, a formyl group, or an amino group. r is an integer of 1 to 6. R ２ and R ３ each independently represents an alkyl group having 1 to 20 carbon atoms, which may have a substituent, or a hydrogen atom.

[0046] In the above general formula (II-1), R ２ and R ３ is any one of the cases where one is an alkyl group having 1 to 20 carbon atoms which may have a substituent and the other is a hydrogen atom, where both are alkyl groups having 1 to 20 carbon atoms which may have a substituent, and where both are hydrogen atoms.

[0047] In the above general formula (II-1), NR２ R ３ and X react with carbonate bonds or hydroxyl groups of polycarbonate diol, or with isocyanate compounds used as raw materials for polyurethane. If an excessive number of substituents X are present, a crosslinked structure may be formed in the polyurethane during the polymerization step in producing the polyurethane, causing gelation, which may result in impaired polymerization stability. Therefore, r, which represents the number of substituents X, is preferably 1 or 2, and more preferably 1.

[0048] Also, R １ The number of carbon atoms in R is 2 to 20, but from the viewpoint of improving the mechanical properties of the resulting polyurethane, １ The number of carbon atoms in R is preferably 3 to 10, more preferably 3 to 6, and even more preferably 4 to 6. ２ and R ３ is an alkyl group having 1 to 20 carbon atoms or a hydrogen atom, but from the viewpoint of improving the mechanical properties of the resulting polyurethane, R ２ and R ３ is preferably an alkyl group having 3 to 10 carbon atoms or a hydrogen atom, more preferably an alkyl group having 3 to 6 carbon atoms or a hydrogen atom, and even more preferably an alkyl group having 4 to 6 carbon atoms or a hydrogen atom.

[0049] Specific examples of the amine represented by the general formula (II-1) include the following: １ is a propylene group having 3 carbon atoms, primary amine compounds such as 3-amino-1-propanal, secondary amine compounds such as 3-methylamino-1-propanal, and tertiary amine compounds such as 3-dimethylamino-1-propanol; １ When R is a butylene group having 4 carbon atoms, a primary amine compound such as 4-amino-1-butanol, a secondary amine compound such as 4-methylamino-1-butanol, or a tertiary amine compound such as 4-dimethylamino-1-butanol; １ When R is a pentylene group having 5 carbon atoms, a primary amine compound such as 5-amino-1-pentanol, a secondary amine compound such as 5-methylamino-1-pentanol, or a tertiary amine compound such as 5-dimethylamino-1-pentanol; １When is a hexylene group having 6 carbon atoms, examples of the amine compound include primary amine compounds such as 6-amino-1-hexanol, secondary amine compounds such as 6-methylamino-1-hexanol and 6-ethylamino-1-hexanol, and tertiary amine compounds such as 6-dimethylamino-1-hexanol and 6-diethylamino-1-hexanol. These compounds may be used alone or in combination of two or more.

[0050] (Third embodiment of nitrogen-containing compound) As a third embodiment, the nitrogen-containing compound can contain at least one selected from the group consisting of primary alkylamines, secondary alkylamines, and tertiary alkylamines. This can further improve the effect of suppressing the production of tetrahydrofuran when the polycarbonate diol composition is heated. Furthermore, by using the polycarbonate diol composition of the present invention, the mechanical properties such as breaking strength, breaking elongation, and elastic modulus, as well as transparency of the obtained polyurethane product can be made more excellent. Furthermore, one embodiment of the primary to tertiary alkylamines includes alkylamines having an amino group in the molecule but no functional groups other than the amino group.

[0051] More specifically, examples of the primary to tertiary alkylamines include trimethylamine, diethylamine, triethylamine, propylamine, dipropylamine, tripropylamine, butylamine, dibutylamine, tributylamine, amylamine, diamylamine, triamylamine, hexylamine, dihexylamine, trihexylamine, heptylamine, diheptylamine, triheptylamine, octylamine, dioctylamine, trioctylamine, nonylamine, dinonylamine, trinonylamine, decylamine, didecylamine, tridecylamine, dodecylamine, didodecylamine, and tridodecylamine. Structural isomers and derivatives of these compounds are also included. These compounds may be used alone or in combination of two or more.

[0052] (Fourth Embodiment of Nitrogen-Containing Compound) As a fourth embodiment, the nitrogen-containing compound can include an amide compound having an amide bond in the molecule.

[0053] Specific examples of the amide compound include amides with a chain skeleton such as acetamide as a primary amide, N-methylacetamide and N-ethylacetamide as secondary amides, and N,N-dimethylacetamide as a tertiary amide, aromatic amides such as benzamide, 2-pyrrolidone as a secondary amide, and cyclic amides such as N-methylpyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, 2-piperidone, and N-methylpiperidone as tertiary amides. These compounds may be used alone or in combination of two or more.

[0054] The polycarbonate diol composition of the present invention may contain both a nitrogen-containing compound that is free in the polycarbonate diol composition and a nitrogen-containing compound that is bonded to or associated with a polycarbonate diol in the polycarbonate diol composition or that is contained as a structural unit of the polycarbonate diol.

[0055] The type of the above-mentioned free nitrogen-containing compound and the type of the above-mentioned nitrogen-containing compound bonded to or associated with the polycarbonate diol or contained as a structural unit of the polycarbonate diol may be the same or different.

[0056] The form of the amine compound bonded to or associated with the polycarbonate diol or contained as part of the structure of the polycarbonate diol is not particularly limited, and examples thereof include a form in which an amino group or a dihydroxy group contained in the primary or secondary amine reacts to form a urethane bond or a carbonate bond in the polycarbonate diol.

[0057] (Total Content of Nitrogen-Containing Compounds) The content of nitrogen-containing compounds in the polycarbonate diol composition of the present invention, in terms of nitrogen atoms, refers to the total content of the following three nitrogen-containing compounds, in terms of nitrogen atoms: - The content of nitrogen-containing compounds free in the polycarbonate diol composition, in terms of nitrogen atoms; - The content of nitrogen-containing compounds bonded to or associated with the polycarbonate diol in the polycarbonate diol composition, in terms of nitrogen atoms; - The content of structural units derived from the nitrogen-containing compounds contained in the polycarbonate diol, in terms of nitrogen atoms.

[0058] The lower limit of the content of the nitrogen-containing compound in the polycarbonate diol composition of the present invention is not particularly limited, and from the viewpoint of suppressing the production of tetrahydrofuran when the polycarbonate diol composition of the present invention is 0.001 ppm by mass or more, preferably 0.01 ppm by mass or more, more preferably 0.1 ppm by mass or more, still more preferably 0.25 ppm by mass or more, even more preferably 0.5 ppm by mass or more, and particularly preferably 1.0 ppm by mass or more, in terms of nitrogen atoms, relative to the total mass of the composition. On the other hand, the upper limit of the content of the nitrogen-containing compound is 5,000 ppm by mass or less, in terms of nitrogen atoms, relative to the total mass of the composition, in terms of suppressing an increase in the molecular weight of the polycarbonate diol and the production of tetrahydrofuran due to cyclization of 1,4-butanediol eliminated from the polycarbonate diol when the polycarbonate diol composition of the present invention is heated. Furthermore, it is preferably 1000 ppm by mass or less, more preferably 200 ppm by mass or less, even more preferably 50 ppm by mass or less, still more preferably 40 ppm by mass or less, particularly preferably 25 ppm by mass or less, and most preferably 10 ppm by mass or less. The above upper and lower limits can be combined in any manner. For example, the content of the nitrogen-containing compound in the polycarbonate diol composition of the present invention can be 0.001 to 5000 ppm by mass, preferably 0.01 to 1000 ppm by mass, more preferably 0.1 to 200 ppm by mass, even more preferably 0.1 to 50 ppm by mass, still more preferably 0.25 to 40 ppm by mass, particularly preferably 0.5 to 25 ppm by mass, and most preferably 1.0 to 10 ppm by mass, in terms of nitrogen atoms, relative to the total mass of the composition.

[0059] In the polycarbonate diol composition of the present invention, the specific method for controlling the content of the nitrogen-containing compound within the above-mentioned numerical range is not particularly limited. For example, when using sugar or the like as a biomass resource as a raw material and fermenting it with bacteria to obtain 1,4-butanediol, nitrogen-containing compounds are by-produced, and the content can be controlled by adjusting the type of bacteria, fermentation time, distillation purification conditions, etc. Furthermore, a person skilled in this field can control the content of the nitrogen-containing compound in the polycarbonate diol composition by appropriately optimizing the production conditions for the polycarbonate diol composition of the present invention using 1,4-butanediol as a raw material, as described below, based on well-known techniques.

[0060] <Phosphorus-containing compound> The inventors of the present invention have found that a phosphorus-containing compound serving as a catalyst deactivator may remain in the finally obtained polycarbonate diol composition, and that when this polycarbonate diol composition is heated, the phosphorus-containing compound promotes the production of tetrahydrofuran. That is, they have found that it is effective to set the content of the phosphorus-containing compound to a threshold value or less in order to suppress the production of tetrahydrofuran.

[0061] The type and origin of the phosphorus-containing compound are not particularly limited, and examples thereof include catalyst deactivators used in the final step of the production process of a polycarbonate diol composition. The phosphorus-containing compound is not particularly limited, and examples thereof include inorganic phosphoric acids such as phosphoric acid and phosphorous acid, and organic phosphoric acid esters such as dibutyl phosphate, tributyl phosphate, trioctyl phosphate, triphenyl phosphate, and triphenyl phosphite.

[0062] (Content of phosphorus-containing compound) In the polycarbonate diol composition of the present invention, the upper limit of the content of the phosphorus-containing compound is not particularly limited, but from the viewpoint of suppressing the production of tetrahydrofuran, it is preferably 50 mass ppm or less, more preferably 40 mass ppm or less, even more preferably 30 mass ppm or less, particularly preferably 20 mass ppm or less, and most preferably 10 mass ppm or less, in terms of phosphorus atoms, relative to the total mass of the polycarbonate diol composition. On the other hand, the lower limit of the content of the phosphorus-containing compound is not particularly limited, but if the content of the phosphorus-containing compound is too low, an active catalyst remains, which may cause the polycarbonate diol composition to turn yellow or excessively promote the reaction when producing polyurethane using the polycarbonate diol composition. Therefore, it is preferably 1 mass ppm or more, more preferably 2 mass ppm or more, even more preferably 3 mass ppm or more, particularly preferably 4 mass ppm or more, and most preferably 5 mass ppm or more, in terms of phosphorus atoms, relative to the total mass of the polycarbonate diol composition. For example, the content of the phosphorus-containing compound in the polycarbonate diol composition of the present invention is, in terms of phosphorus atoms, preferably 1 ppm by mass to 50 ppm by mass, more preferably 2 ppm by mass to 40 ppm by mass, even more preferably 3 ppm by mass to 30 ppm by mass, particularly preferably 4 ppm by mass to 20 ppm by mass, and most preferably 5 ppm by mass to 10 ppm by mass, relative to the total mass of the composition.

[0063] In the polycarbonate diol composition of the present invention, the specific method for controlling the content of the phosphorus-containing compound within the above-mentioned numerical range is not particularly limited, and a person skilled in the art can control it by appropriately optimizing the production conditions of the polycarbonate diol composition of the present invention, which will be described later, based on well-known techniques.

[0064] <Metal-Containing Compound> By setting the content of the metal-containing compound in the polycarbonate diol composition of the present invention to a threshold value or less, the effect of suppressing the production of tetrahydrofuran when the polycarbonate diol composition is heated can be further improved.

[0065] The type and origin of the metal-containing compound are not particularly limited, and examples thereof include transesterification catalysts (hereinafter, sometimes simply referred to as "catalysts") used to promote transesterification in the production process of a polycarbonate diol composition.

[0066]

[0009] Through investigations by the present inventors, it has been found that metal-containing compounds such as the catalyst may remain in the finally obtained polycarbonate diol composition, and that when this polycarbonate diol composition is heated, the metal-containing compounds promote the production of tetrahydrofuran, or when polyurethane is produced using the polycarbonate diol, the metal-containing compounds excessively promote the polymerization reaction of polyurethane, causing coloration or turbidity in the obtained polycarbonate diol composition. In other words, it has been found that in order to suppress the production of tetrahydrofuran, it is effective to set the content of the metal-containing compounds to a threshold value or less.

[0067] The metal-containing compound derived from a catalyst useful as a transesterification catalyst is contained depending on the catalyst used, and is not particularly limited. Examples include Group 1 metals of the long period periodic table (hereinafter simply referred to as the "periodic table"), such as lithium, sodium, potassium, rubidium, and cesium; Group 2 metals of the periodic table, such as magnesium, calcium, strontium, and barium; Group 4 metals of the periodic table, such as titanium and zirconium; Group 5 metals of the periodic table, such as hafnium; Group 9 metals of the periodic table, such as cobalt; Group 12 metals of the periodic table, such as zinc; Group 13 metals of the periodic table, such as aluminum; Group 14 metals of the periodic table, such as germanium, tin, and lead; Group 15 metals of the periodic table, such as antimony and bismuth; and lanthanoid metals, such as lanthanum, cerium, europium, and ytterbium.

[0068] Among these, from the viewpoints of high transesterification reaction rate and suppressing poor appearance of the polycarbonate diol composition of the present invention, metals of Group 1, 2, 4, 5, 9, 12, 13, and 14 of the periodic table are preferred, metals of Group 1, 2, and 4 of the periodic table are more preferred, and metals of Group 2 and 4 of the periodic table are even more preferred. Among the metals of Group 2 and 4 of the periodic table, magnesium, calcium, barium, titanium, and zirconium are preferred, calcium, magnesium, and titanium are more preferred, magnesium and titanium are even more preferred, and titanium is particularly preferred.

[0069] (Metal-Containing Compound Content) In the polycarbonate diol composition of the present invention, the upper limit of the metal-containing compound content is not particularly limited, but from the viewpoint of suppressing the generation of tetrahydrofuran when the polycarbonate diol composition is heated, it can be 50 mass ppm or less in terms of metal atoms, more preferably 40 mass ppm or less, even more preferably 30 mass ppm or less, particularly preferably 20 mass ppm or less, and most preferably 10 mass ppm or less, relative to the total mass of the polycarbonate diol composition. On the other hand, the lower limit of the metal-containing compound content is not particularly limited, and it may be that no metal-containing compound is contained (0 mass ppm), or, from the viewpoint of economic efficiency such as production costs for reducing the metal-containing compound, it can be 1 mass ppm or more in terms of metal atoms, more preferably 2 mass ppm or more, even more preferably 3 mass ppm or more, particularly preferably 4 mass ppm or more, and most preferably 5 mass ppm or more. The above upper and lower limits can be combined arbitrarily. For example, the content of the metal-containing compound in the polycarbonate diol composition of the present invention may be zero (0 ppm by mass), or may be 1 ppm by mass or more and 50 ppm by mass or less, more preferably 2 ppm by mass or more and 40 ppm by mass or less, even more preferably 3 ppm by mass or more and 30 ppm by mass or less, particularly preferably 4 ppm by mass or more and 20 ppm by mass or less, and most preferably 5 ppm by mass or more and 10 ppm by mass or less, in terms of metal atoms, relative to the total mass of the composition.

[0070] In the polycarbonate diol composition of the present invention, the specific method for controlling the content of the metal-containing compound within the above-mentioned numerical range is not particularly limited, and a person skilled in the art can control it by appropriately optimizing the production conditions of the polycarbonate diol composition of the present invention, which will be described later, based on well-known techniques.

[0071] <Ratio of Phosphorus to Metal> In the polycarbonate diol composition of the present invention, the upper limit of the ratio (unit: equivalent) of the content of the phosphorus atom-containing compound in terms of phosphorus atoms to the content of the metal-containing compound in terms of metal atoms is not particularly limited, but from the viewpoint of suppressing the generation of tetrahydrofuran when the polycarbonate diol composition is heated, it is preferably 3.0 equivalents or less, more preferably 2.0 equivalents or less, even more preferably 1.5 equivalents or less, and particularly preferably 1.2 equivalents or less. On the other hand, the lower limit of the content ratio of phosphorus atoms to metal atoms is not particularly limited, but from the viewpoint of suppressing coloration of the polycarbonate diol composition of the present invention and suppressing excessive promotion of the reaction when producing polyurethane using the polycarbonate diol composition, it is preferably 0.1 equivalents or more, more preferably 0.3 equivalents or more, even more preferably 0.5 equivalents or more, and particularly preferably 0.8 equivalents or more. The above upper and lower limits can be combined arbitrarily. For example, in the polycarbonate diol composition of the present invention, the ratio (unit: equivalent) of the content of the phosphorus atom-containing compound in terms of phosphorus atoms to the content of the metal-containing compound in terms of metal atoms is preferably 0.1 equivalents or more and 3.0 equivalents or less, more preferably 0.3 equivalents or more and 2.0 equivalents or less, even more preferably 0.5 equivalents or more and 1.5 equivalents or less, and particularly preferably 0.8 equivalents or more and 1.2 equivalents or less, relative to the total mass of the composition.

[0072] <Method for Producing Polycarbonate Diol> The method for producing the polycarbonate diol of the present invention is not particularly limited, and for example, known methods for producing polycarbonate diols described in Schnell, Polymer Reviews, Vol. 9, pp. 9-20 (1994), WO 2015 / 199070, etc. can be used.

[0073]

[0044] As a specific embodiment of the method for producing a polycarbonate diol of the present invention, a method can be mentioned in which the dihydroxy compound composition described above and a carbonate compound described below are polycondensed by a transesterification reaction in the presence of a catalyst described below to obtain a polycarbonate diol.

[0074] As one embodiment of the method for producing a polycarbonate diol of the present invention, a method using diphenyl carbonate, a carbonate compound, will be described below. The production of a polycarbonate diol can be carried out in two stages. In the first stage reaction, 1,4-butanediol, the hydroxy group-containing compound (2) as needed, and diphenyl carbonate are mixed in a molar ratio of 20:1 to 1:10, preferably 10:1 to 1:2, and after adding a catalyst described below, the mixture is reacted at 100 to 250°C under normal pressure, and a reaction product containing a low-molecular-weight polycarbonate diol is obtained while removing phenol produced by decomposition of diphenyl carbonate from the reaction system. In the second-stage reaction, the reaction product of the first stage is heated at 130 to 250°C under reduced pressure to self-condense the low-molecular-weight polycarbonate diol while removing phenol, unreacted 1,4-butanediol, and the hydroxy group-containing compound (2) used as needed from the reaction system, to obtain a polycarbonate diol having a predetermined molecular weight.

[0075] (Carbonate Compound) The carbonate compound usable in the method for producing the polycarbonate diol of the present invention is not particularly limited as long as it does not impair the effects of the present invention, and examples thereof include dialkyl carbonates such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and dibutyl carbonate; diaryl carbonates such as diphenyl carbonate; alkylene carbonates such as ethylene carbonate, trimethylene carbonate, 1,2-propylene carbonate, 1,2-butylene carbonate, 1,3-butylene carbonate, and 1,2-pentylene carbonate; etc. One or more carbonates from these can be used as a raw material. Among these, from the viewpoints of reactivity with 1,4-butanediol, ease of availability, and ease of setting polymerization reaction conditions, it is preferable to use one or more carbonate compounds selected from the group consisting of dimethyl carbonate, diethyl carbonate, diphenyl carbonate, dibutyl carbonate, and ethylene carbonate. The amount of the carbonate compound used is not particularly limited, and a person skilled in the art can use the conditions described in WO 2015 / 199070 by optimizing them as appropriate according to known techniques, for example.

[0076] (Catalyst) In the method for producing a polycarbonate diol of the present invention, when 1,4-butanediol and the hydroxy group-containing compound (2) used as needed are polycondensed with a carbonate compound via a transesterification reaction to obtain a polycarbonate diol, a known transesterification catalyst (hereinafter simply referred to as "catalyst") used in the synthesis of polycarbonate diols can be used as a catalyst to promote the transesterification reaction. In this case, if an excessive amount of catalyst remains in the obtained polycarbonate diol, it may inhibit or excessively promote the reaction when producing a polyurethane using the polycarbonate diol. The type and amount of catalyst used, and the amount of catalyst remaining in the polycarbonate diol are not particularly limited. As the catalyst, for example, catalysts described in WO 2015 / 199070 and JP 2022-92121 A can be appropriately optimized and used by a person skilled in the art according to known techniques.

[0077] In the method for producing a polycarbonate diol of the present invention, it is preferable to use a catalyst containing a magnesium atom or a catalyst containing a titanium atom as the catalyst. The catalyst containing a magnesium atom is not particularly limited, and examples thereof include magnesium hydroxide, magnesium hydrogencarbonate, magnesium carbonate, magnesium acetate, magnesium stearate, and magnesium phenylphosphate. The catalyst containing a titanium atom is not particularly limited, and examples thereof include titanium alkoxides such as tetraethyl titanate, tetraisopropyl titanate, and tetra-n-butyl titanate; and titanium halides such as titanium tetrachloride. In particular, in the present invention, the use of a catalyst containing a titanium atom makes it possible to improve the yield of polycarbonate diol, suppress excessive increases in the molecular weight of the polycarbonate diol, and reduce the amount of catalyst residue in the polycarbonate diol obtained with a relatively small amount of catalyst, even when producing a polycarbonate diol using 1,4-butanediol and the hydroxy group-containing compound (2) used as needed. The amount of the catalyst containing titanium atoms used can be 50 ppm by mass or less in terms of titanium atoms relative to the total mass of the dihydroxy compound composition.

[0078] (Catalyst Deactivator) As mentioned above, when a catalyst is used during the polymerization reaction, the catalyst usually remains in the resulting polycarbonate diol. The remaining catalyst may cause an increase in molecular weight or a change in composition when the polycarbonate diol is heated, or may make it impossible to control the polyurethane reaction. In order to suppress the effects of this remaining catalyst, if necessary, a catalyst deactivator such as a phosphorus-based compound can be added in an amount approximately equimolar to the transesterification catalyst used to deactivate the transesterification catalyst. Furthermore, after the addition, the transesterification catalyst can be efficiently deactivated by heat treatment or the like. The type and amount of the catalyst deactivator, and the conditions for the heat treatment are not particularly limited. As the catalyst deactivator, for example, the catalyst deactivators described in WO 2015 / 199070 and JP 2022-92121 A can be used by optimizing them appropriately according to known techniques by those skilled in the art.

[0079] (Purification) The reaction product obtained by the transesterification reaction contains impurities not having a hydroxyl group at the polymer terminal, phenol, raw material dihydroxy compound, raw material carbonate compound, by-product low-boiling cyclic carbonate, and added catalyst, etc., and can be purified for the purpose of removing these. The purification conditions are not particularly limited. For example, the conditions described in JP 2022-92121 A can be appropriately optimized and used by a person skilled in the art according to known techniques.

[0080] (Molecular Weight of Polycarbonate Diol) In the method for producing a polycarbonate diol of the present invention, the number average molecular weight (Mn) of the obtained polycarbonate diol is preferably 250 or more and 5,000 or less, more preferably 300 or more and 4,000 or less, and even more preferably 400 or more and 3,000 or less, for the same reasons as those described for the polycarbonate diol of the present invention.

[0081] <Polyurethane> The polyurethane of the present invention is produced using the polycarbonate diol composition of the present invention and an isocyanate compound as raw materials. Since the polyurethane of the present invention is produced using the polycarbonate diol composition of the present invention as a raw material, the polyurethane product obtained using this polycarbonate diol composition can have excellent mechanical properties such as breaking strength, breaking elongation, and elastic modulus, as well as excellent transparency. Furthermore, when producing polyurethane using the polycarbonate diol composition of the present invention as a raw material, the production of tetrahydrofuran is suppressed. As a result, silver streaks and foaming due to tetrahydrofuran evaporation during heat molding of the obtained polyurethane can be reduced, and the resulting polyurethane product has good product appearance and mechanical properties.

[0082] The method for producing the polyurethane of the present invention is not particularly limited, and those skilled in the art can use known polyurethane reaction conditions described in, for example, WO 2015 / 016261 and WO 2018 / 088575, by optimizing them as appropriate in accordance with known techniques.

[0083] For example, the polyurethane of the present invention can be produced by reacting the polycarbonate diol composition of the present invention with a polyol other than the polycarbonate diol of the present invention, which is used if necessary, an isocyanate compound described below, and a chain extender described below, which is also used if necessary, at a temperature in the range of room temperature to 200°C.

[0084] When a chain extender is used, the chain extender may be added from the beginning of the reaction or during the reaction. For example, the polyurethane of the present invention can be produced by first reacting the polycarbonate diol composition of the present invention with an excess amount of polyisocyanate to produce a prepolymer having an isocyanate group at its terminal, and then adding a chain extender to react with the prepolymer to increase the degree of polymerization of the polymer.

[0085] (Isocyanate-based compound) As the isocyanate-based compound used in the production of the polyurethane of the present invention, a known isocyanate-based compound used in the production of polyurethane can be used. The isocyanate-based compound is not particularly limited, and for example, the isocyanate-based compounds described in WO 2015 / 016261 and WO 2018 / 088575 can be used.

[0086] (Chain extender) As the chain extender used in the production of the polyurethane of the present invention, a known chain extender used in the production of polyurethane can be used. The chain extender is not particularly limited, and examples thereof include diols, amines, water, etc. described in WO 2015 / 016261 and WO 2018 / 088575.

[0087] (Chain Terminating Agent) When producing the polyurethane of the present invention, a known chain terminator used in the production of polyurethanes can be used as needed to control the molecular weight of the polyurethane. The chain terminator is not particularly limited, and examples thereof include compounds having one active hydrogen group, such as monohydric alcohols and secondary amines, as described in WO 2015 / 016261 and WO 2018 / 088575.

[0088] (Catalyst) When producing the polyurethane of the present invention, a known catalyst used in producing polyurethanes can be used. The catalyst is not particularly limited, and for example, known polymerization catalysts such as tertiary amines and organic metal salts of tin, titanium, etc., as described in WO 2015 / 016261 and WO 2018 / 088575 can be used.

[0089] (Solvent) When producing the polyurethane of the present invention, a solvent may be used as needed. The solvent is not particularly limited, and examples thereof include the solvents described in WO 2015 / 016261 and WO 2018 / 088575.

[0090] (Amounts and Methods of Use) In the method for producing a polyurethane of the present invention, the amounts and methods of use of the polyisocyanate, the chain extender, the chain terminator, the catalyst, and the solvent are not particularly limited, and a person skilled in the art can use the conditions described in WO 2015 / 016261 and WO 2018 / 088575 by appropriately optimizing them in accordance with known techniques.

[0091] (Weight-average molecular weight (Mw) of polyurethane) The weight-average molecular weight (Mw) of the polyurethane of the present invention is not particularly limited, and from the viewpoint of achieving a good balance between the mechanical properties and chemical resistance of the resulting polyurethane, it is preferably from 50,000 to 500,000, more preferably from 100,000 to 300,000, and even more preferably from 150,000 to 200,000.

[0092] <Uses of Polyurethane> The polyurethane of the present invention has good mechanical properties and transparency, and therefore can be widely used in foams, elastomers, elastic fibers, paints such as water-based polyurethane paints, fibers, pressure-sensitive adhesives, adhesives, flooring materials, sealants, medical materials, artificial leather, synthetic leather, coating agents, active energy radiation-curable polymer compositions, and the like.

[0093] [Effects] The polycarbonate diol composition of the present invention, containing the nitrogen-containing compound described above, can suppress the generation of tetrahydrofuran during heat treatment. While the reason for this is unclear, it is presumed as follows. The metal catalyst used in the transesterification reaction remains in the polycarbonate diol composition. This metal catalyst coordinates to the 1,4-butanediol-derived structural units in the polycarbonate diol terminals, particularly at the polycarbonate diol terminals, causing depolymerization of the hydroxyl terminals. The resulting 1,4-butanediol then undergoes a cyclization reaction to produce tetrahydrofuran. Alternatively, the 1,4-butanediol-derived structural units at the polycarbonate diol terminals to which the metal catalyst has been coordinated undergo cyclization accompanied by decarboxylation to produce tetrahydrofuran. However, it is presumed that the nitrogen-containing compound coordinates to the metal catalyst, preventing the metal catalyst from coordinating to the 1,4-butanediol-derived repeating units, thereby suppressing the generation of tetrahydrofuran.

[0094] Furthermore, by setting the content of the phosphorus-containing compound in the polycarbonate diol composition of the present invention to a threshold value or less, the generation of tetrahydrofuran can be further suppressed. The reason for this is unclear, but is presumed to be as follows. That is, the phosphorus-containing compound is sometimes added to deactivate the metal catalyst in the final stage of polycarbonate diol synthesis, and a portion of it remains in the polycarbonate diol composition. In such cases, the remaining phosphorus-containing compound acts as a catalyst in the above-mentioned tetrahydrofuran production reaction, promoting the production of tetrahydrofuran. Therefore, it is presumed that the generation of tetrahydrofuran can be further suppressed by setting the content of the phosphorus-containing compound to a threshold value or less.

[0095] The polycarbonate diol composition of the present invention suppresses the generation of tetrahydrofuran during heating. As a result, when a polyurethane is produced using the polycarbonate diol composition of the present invention and the polyurethane is molded and processed, silver streaks and foaming due to the evaporation of tetrahydrofuran can be reduced, and a high-quality polyurethane product excellent in quality such as product appearance and mechanical properties can be produced.

[0096] The present invention will be explained in more detail below by way of examples and comparative examples, but the present invention is not limited to these examples as long as it does not depart from the gist of the invention.

[0097] [Raw Materials Used] The raw materials and their abbreviations used in the Examples and Comparative Examples are as follows: THF: tetrahydrofuran (manufactured by Tokyo Chemical Industry Co., Ltd.) <Diols> 14BD: 1,4-butanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) 16HD: 1,6-hexanediol (manufactured by BASF Corporation) ISB: isosorbide (manufactured by Roquette Corporation) <Additives> 4-amino-1-butanol (manufactured by Tokyo Chemical Industry Co., Ltd.) Dihexylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) Trihexylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) Phosphoric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) <Polycarbonate diol (PCD)> PCD-1 (manufactured by Mitsubishi Chemical Corporation, polycarbonate diol whose diol component is solely 1,4-butanediol, number average molecular weight calculated as hydroxyl groups: 985) PCD-2 (manufactured by Mitsubishi Chemical Corporation, polycarbonate diol whose diol components are 1,4-butanediol and isosorbide, 14BD / ISB ratio in PCD = 63 / 37, number average molecular weight converted into hydroxyl groups: 843) PCD-3 (polycarbonate diol whose diol components are 1,4-butanediol and 1,6-hexanediol, 14BD / 16HD ratio in PCD = 75 / 25, number average molecular weight converted into hydroxyl groups: 1860) <Raw urethane materials> MDI: diphenylmethane diisocyanate (manufactured by Tosoh Corporation) U-830: dioctyltin monodecanoate (trade name: Neostan U-830, manufactured by Nitto Kasei Co., Ltd.) DMF: N,N-dimethylformamide dehydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0098] [Evaluation Methods] The evaluation methods for each physical property value are as follows: <Contents of Nitrogen-Containing Compound and Phosphorus Atom-Containing Compound in Polycarbonate Diol Composition> For the polycarbonate diol compositions of the Examples and Comparative Examples, the contents of the nitrogen-containing compound in terms of nitrogen atoms and the contents of the phosphorus atom-containing compound in terms of phosphorus atoms in the polycarbonate diol composition were calculated from the structures and blending amounts of the nitrogen-containing compound and phosphorus atom-containing compound blended in the polycarbonate diol composition.

[0099] <Amount of Tetrahydrofuran Produced in Polycarbonate Diol Composition> Acetonitrile was added to 1.0 g of the heat-treated polycarbonate diol composition obtained in the Examples and Comparative Examples to prepare 10 mL of a solution. Water was added to 1 mL of the prepared solution to obtain 10 mL of an aqueous suspension. Next, the supernatant of the aqueous suspension was collected and filtered using a filter with a pore size of 0.45 μm, and this was used as a GC measurement sample. Using a gas chromatograph (GC) measurement device and a gas chromatography absolute calibration curve method, the amount of tetrahydrofuran (THF) in the GC measurement sample was quantified under the following GC measurement conditions, and the amount of THF produced in the polycarbonate diol composition was calculated from the quantitative value. In the gas chromatography absolute calibration curve method, the amount of tetrahydrofuran (THF) produced (unit: mass ppm) was calculated from a calibration curve previously prepared using THF.

[0100] (GC measurement conditions) GC apparatus: gas chromatogram measuring apparatus (product name: GC-2014, manufactured by Shimadzu Corporation) Column: capillary GC column (product name: Rtx-1, manufactured by Restek, size: inner diameter 0.25 mm, length 30 m, film thickness 0.25 μm) Detector: hydrogen flame ionization detector (FID) Column temperature: 40°C (retention time 7 minutes) → temperature increase at 15°C / min → 200°C (retention time 0 minutes) Injection amount: 1 μL (split ratio: 1 / 100) Injection port temperature: 100°C Detector temperature: 260°C (FID detector)

[0101] <Weight-average molecular weight (Mw) and number-average molecular weight (Mn) of polyurethane> The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polyurethanes obtained in the examples and comparative examples were determined using gel permeation chromatography (GPC measurement) according to the following procedure.

[0102] The polyurethane sample was dissolved in dimethylacetamide (containing 0.3% by mass of anhydrous lithium bromide) to a polyurethane concentration of 0.07% by mass, and this was used as the sample for GPC measurement. Using a GPC system (manufactured by Tosoh Corporation, model name: HLC-8420, column: two Tosoh Corporation TSKgel SuperAWM-H columns), GPC measurement was performed under the following conditions: sample injection volume of approximately 40 μL, column temperature of 40°C, measurement solvent (mobile phase) of dimethylacetamide (containing 0.3% by mass of anhydrous lithium bromide), and flow rate of 0.6 mL / min. The molecular weight of the polyurethane was measured using a commercially available monodisperse polystyrene solution as a standard sample to determine the number average molecular weight (Mn), weight average molecular weight (Mw), and molecular weight distribution (Mw / Mn) in terms of standard polystyrene.

[0103] <Mechanical Properties of Polyurethane> As an index of the mechanical properties of polyurethane, tensile tests were carried out on polyurethane using the following methods to evaluate various mechanical properties.

[0104] The polyurethane solutions obtained in the examples and comparative examples were applied to a 0.1 mm thick fluororesin sheet (product name: Fluorine Tape "Nitoflon 900", manufactured by Nitto Denko Corporation) using an applicator with a clearance of 500 μm. The sheet was dried at 80°C for 1 hour, then at 100°C for 0.5 hours, and then at 100°C under vacuum for 1.0 hour to dry and remove the solvent (DMF). The sheet was then left to stand at a constant temperature and humidity of 23°C and 55% RH for at least 12 hours to obtain a laminate film with a polyurethane layer formed on the surface of the fluororesin sheet. The thickness of the polyurethane layer after drying was 90±20 μm. After peeling the polyurethane layer from the resulting laminate film, strips of polyurethane film (150 mm long, 10 mm wide, 90±20 μm thick) were cut out and used as sample pieces for tensile testing and elastic modulus measurement.

[0105] (Tensile Test) A tensile test was carried out on the above-mentioned tensile test specimens in accordance with JIS K6301 (2010) using a bench-top precision universal testing machine (manufactured by Shimadzu Corporation, product name: Autograph AGS-X) at a chuck distance of 50 mm, a tensile speed of 500 mm / min, and a temperature of 23°C (relative humidity of 60%). Measurements were carried out using three tensile test specimens, and the 100% modulus and 300% modulus, as well as the average value and standard deviation of the stress (breaking strength) and elongation (breaking elongation) at the time the specimen broke, were measured.

[0106] (Elastic Modulus) The above tensile test specimens were subjected to a tensile test in accordance with JIS K7161 using a bench-top precision universal testing machine (Shimadzu Corporation, product name: Autograph AGS-X) and an extensometer (DSES-1000, Shimadzu Corporation) at a chuck distance of 50 mm, a tensile speed of 1 mm / min, and a temperature of 23°C (relative humidity of 60%) up to an elongation of 10%. Measurements were performed using three tensile test specimens, and the average value and standard deviation of the tensile modulus were calculated from the slope of the stress-strain curve for two points in the range of the initial strain of the film (0.2 to 0.8%) based on the extensometer. The coefficient of variation of the elastic modulus was calculated using the following equation:

[0107] The coefficients of variation for 100% modulus, 300% modulus, breaking strength, breaking elongation, and elastic modulus were calculated using the following formula: Coefficient of variation (%) = (standard deviation / average value) x 100

[0108] <Transparency (YI value)> For the polyurethanes obtained in the examples and comparative examples, the yellow index (YI) value of a square polyurethane film (3 cm long, 3 cm wide, 90±20 μm thick) was measured as an index of transparency using a colorimeter (ZE 6000, manufactured by Nippon Denshoku Industries Co., Ltd.) by the transmittance measurement method in accordance with JIS K 7373. A smaller YI value indicates better color.

[0109] <Evaluation of Polycarbonate Diol (1)> The following experiment was carried out to investigate the influence of a nitrogen-containing compound in a polycarbonate diol composition using only 14BD as a diol raw material on the amount of tetrahydrofuran produced when the polycarbonate diol composition was heated.

[0110] Example 1 A stirrer and 5 g of PCD-1 as polycarbonate diol were placed in a glass reaction vessel (outer diameter 18 mm, manufactured by EYELA) for a personal organic synthesis apparatus (apparatus name: PPM-5512A, manufactured by EYELA). Furthermore, trihexylamine was added to the reaction vessel so that the concentration was 1 ppm by mass in terms of nitrogen atoms and phosphoric acid was added to the reaction vessel so that the concentration was 5 ppm by mass in terms of phosphorus atoms, relative to the total mass of the polycarbonate diol. The atmosphere inside the reaction vessel was then replaced with a nitrogen atmosphere. The reaction vessel was then attached to the personal organic synthesis apparatus, and the gas phase of the reaction vessel was cooled to 5°C using a cooling cartridge. The liquid phase (contents) in the reaction vessel was then heated to a temperature of 160°C. Once the contents had dissolved, stirring was initiated and the reaction vessel was heated and stirred for 6 hours. The contents were then allowed to cool to room temperature. The resulting contents were evaluated as described above, and the evaluation results are shown in Table 1.

[0111] Comparative Example 1 The same operation as in Example 1 was carried out, except that trihexylamine was not used. The contents obtained were evaluated as described above, and the evaluation results are shown in Table 1.

[0112] [Example 2] The same operation as in Example 1 was carried out, except that 4-amino-1-butanol was used instead of trihexylamine. The contents obtained were evaluated as described above, and the evaluation results are shown in Table 1.

[0113] [Example 3] The same operation as in Example 1 was carried out, except that the amount of trihexylamine was changed to 10 ppm by mass in terms of nitrogen atoms. The obtained contents were evaluated as described above, and the evaluation results are shown in Table 1.

[0114] [Example 4] The same operation as in Example 1 was carried out, except that the amount of trihexylamine was changed to 50 ppm by mass in terms of nitrogen atoms. The obtained contents were evaluated as described above, and the evaluation results are shown in Table 1.

[0115] [Example 5] The same operation as in Example 1 was carried out, except that the amount of trihexylamine was changed to 0.2 ppm by mass in terms of nitrogen atoms. The contents obtained were evaluated as described above, and the evaluation results are shown in Table 1.

[0116] [Example 6] The same operation as in Example 1 was carried out, except that the amount of trihexylamine was changed to 0.5 ppm by mass in terms of nitrogen atoms. The obtained contents were evaluated as described above, and the evaluation results are shown in Table 1.

[0117] [Example 7] The same operation as in Example 1 was carried out except that dihexylamine was used instead of trihexylamine. The contents obtained were evaluated as described above, and the evaluation results are shown in Table 1.

[0118]

[0119] The following can be seen from Table 1: In Examples 1 to 7, the amount of tetrahydrofuran produced after the heat treatment of the polycarbonate diol composition was small. On the other hand, in Comparative Example 1, the amount of tetrahydrofuran produced was larger than in Examples 1 to 7 because the polycarbonate diol composition did not contain a nitrogen-containing compound.

[0120] The graph in Figure 1 shows the relationship between the nitrogen atom-equivalent content of the nitrogen-containing compound in the polycarbonate diol composition and the amount of tetrahydrofuran (THF) produced in the polycarbonate diol composition after heat treatment for Examples 1 to 7 and Comparative Example 1. Figure 1 shows that the amount of tetrahydrofuran produced in the polycarbonate diol composition after heat treatment tends to decrease as the content of the nitrogen-containing compound in the polycarbonate diol composition increases.

[0121] <Evaluation of Polycarbonate Diol (2)> The following experiment was carried out to investigate the effect of a nitrogen-containing compound (trihexylamine) in a polycarbonate diol composition using 14BD and other diols as diol raw materials on the amount of tetrahydrofuran produced when the polycarbonate diol composition was heated.

[0122] Example 8 A stirrer and 5 g of PCD-2 as polycarbonate diol were placed in a glass reaction vessel (outer diameter 18 mm, manufactured by EYELA) for a personal organic synthesis apparatus (apparatus name: PPM-5512A, manufactured by EYELA). Furthermore, trihexylamine was added to the reaction vessel so that the concentration was 1 ppm by mass in terms of nitrogen atoms and phosphoric acid was added to the reaction vessel so that the concentration was 5 ppm by mass in terms of phosphorus atoms, relative to the total mass of the polycarbonate diol. The atmosphere inside the reaction vessel was then replaced with a nitrogen atmosphere. The reaction vessel was then attached to the personal organic synthesis apparatus, and the gas phase of the reaction vessel was cooled to 5°C using a cooling cartridge. The liquid phase (contents) in the reaction vessel was then heated to a temperature of 160°C. Once the contents had dissolved, stirring was initiated and the reaction vessel was heated and stirred for 6 hours. The contents were then allowed to cool to room temperature. The resulting contents were evaluated as described above, and the evaluation results are shown in Table 2.

[0123] Comparative Example 2 The same operation as in Example 8 was carried out, except that trihexylamine was not used. The contents obtained were evaluated as described above, and the evaluation results are shown in Table 2.

[0124] [Example 9] The same operation as in Example 8 was carried out, except that the amount of trihexylamine was changed to 10 ppm by mass in terms of nitrogen atoms. The contents obtained were evaluated as described above, and the evaluation results are shown in Table 2.

[0125] [Example 10] The same operation as in Example 8 was carried out, except that the amount of trihexylamine in Example 1 was changed to 40 ppm by mass in terms of nitrogen atoms. The contents obtained were evaluated as described above, and the evaluation results are shown in Table 2.

[0126] Example 11 A stirrer and 5 g of PCD-3 as polycarbonate diol were placed in a glass reaction vessel (outer diameter 18 mm, manufactured by EYELA) for a personal organic synthesis apparatus (apparatus name: PPM-5512A, manufactured by EYELA). Furthermore, trihexylamine was added so that the concentration was 1 ppm by mass in terms of nitrogen atoms relative to the total mass of the polycarbonate diol, and then the reaction vessel was purged with a nitrogen atmosphere. The reaction vessel was then attached to the personal organic synthesis apparatus, and the gas phase of the reaction vessel was cooled to 5°C using a cooling cartridge. The liquid phase (contents) in the reaction vessel was then heated to a temperature of 160°C. Once the contents had dissolved, stirring was initiated and the mixture was heated and stirred for 6 hours. The contents were then allowed to cool to room temperature. The resulting contents were evaluated as described above, and the evaluation results are shown in Table 2.

[0127] Comparative Example 3 The same operation as in Example 11 was carried out, except that trihexylamine was not used. The contents obtained were evaluated as described above, and the evaluation results are shown in Table 2.

[0128] [Example 12] The same operation as in Example 11 was carried out, except that the amount of trihexylamine was changed to 10 ppm by mass in terms of nitrogen atoms. The obtained contents were evaluated as described above, and the evaluation results are shown in Table 2.

[0129] [Example 13] The same operation as in Example 11 was carried out, except that the amount of trihexylamine was changed to 40 ppm by mass in terms of nitrogen atoms. The obtained contents were evaluated as described above, and the evaluation results are shown in Table 2.

[0130]

[0131] Regarding the evaluation results in Table 2, Figure 2 shows the relationship between the content of the nitrogen-containing compound (trihexylamine) in the polycarbonate diol composition in terms of nitrogen atoms contained therein and the amount of tetrahydrofuran (THF) produced in the polycarbonate diol composition after heat treatment for Examples 8 to 10 and Comparative Example 2. Figure 3 shows the relationship between the content of the nitrogen-containing compound (trihexylamine) in the polycarbonate diol composition in terms of nitrogen atoms contained therein and the amount of tetrahydrofuran (THF) produced in the polycarbonate diol composition after heat treatment for Examples 11 to 13 and Comparative Example 3.

[0132] The following can be seen from Table 2 and Figures 2 and 3. In Examples 8 to 10, the amount of tetrahydrofuran produced after the polycarbonate diol composition was heat-treated was small. Figure 2 confirms that the presence of a nitrogen-containing compound in the polycarbonate diol composition reduces the amount of tetrahydrofuran produced in the polycarbonate diol composition after heat treatment. In particular, Figure 2 shows that the amount of tetrahydrofuran produced is small when the content of the nitrogen-containing compound in the polycarbonate diol composition is around 10 ppm by mass.

[0133] Furthermore, the amount of tetrahydrofuran produced after the heat treatment of the polycarbonate diol composition was small in Examples 11 to 13. It was confirmed from Fig. 3 that the presence of a nitrogen-containing compound in the polycarbonate diol composition reduces the amount of tetrahydrofuran produced in the polycarbonate diol composition after the heat treatment.

[0134] From Table 2 and Figures 2 and 3, it can be seen that even in copolymerized PCD using 1,4-butanediol and other diols, the amount of tetrahydrofuran produced can be reduced by adding a nitrogen-containing compound to the polycarbonate diol composition.

[0135] <Evaluation of Polyurethane> The following experiment was carried out to examine the influence of the nitrogen-containing compound in the polycarbonate diol composition on the mechanical properties and transparency (coloration) of the polyurethane obtained using the polycarbonate diol composition.

[0136] Example 14: Trihexylamine was added to PCD-1 stored in a 0.5 L can to a concentration of 0.5 ppm by mass in terms of nitrogen atoms, and phosphoric acid was added to a concentration of 5 ppm by mass in terms of phosphorus atoms, followed by heating in an oil bath at 160 °C for 6 hours. Thereafter, 64.8 g of the heated and melted PCD was placed in a separable flask equipped with a thermocouple and a condenser. Furthermore, 6.0 g of 14BD as a chain extender, 0.02 g of U-830 as a catalyst, and 242 g of DMF as a reaction solvent were placed in the flask, immersed in an oil bath set at 55 °C, and stirred and mixed at a stirring speed of 60 rpm until homogeneous. The amount of water in the reaction solution in the flask was measured, and the amount of MDI consumed by water was calculated. The amount sampled and extracted was also recorded, and the amount of each raw material charged was corrected. MDI, an isocyanate compound with an NCO / OH molar ratio of 0.900 (including correction for water content), was added in a solid state to the reaction solution using a funnel, and the mixture was stirred and mixed at a stirring speed of 60 rpm until uniform. In this specification, the "NCO / OH molar ratio" refers to the ratio (molar ratio) of the total amount of MDI (number of moles) to the value obtained by subtracting the total amount of water (number of moles) contained from the total amount of polycarbonate diol and 14BD (number of moles) at the time of MDI addition. An exothermic peak accompanied by a temperature rise of +10 to +15°C was observed immediately after the addition of MDI, and 5 minutes after the exothermic peak had subsided, the oil bath temperature was set to 70°C and the temperature was increased.

[0137] One hour after the addition of MDI, the molecular weight of the polyurethane in the reaction solution was measured to confirm whether the target molecular weight had been reached. If the target molecular weight had not been reached, additional MDI was added in an amount equivalent to an NCO / OH molar ratio of 0.005 to 0.015, and the reaction was continued for another 30 minutes or more, after which the molecular weight of the polyurethane in the reaction solution was measured. Additional addition of MDI and molecular weight measurement were repeated until the target Mw was reached. A polyurethane solution containing polyurethane with an Mw of 151,557 was finally obtained. The evaluation results of the obtained polyurethane are shown in Table 3.

[0138] Comparative Example 4 A polyurethane solution was obtained by polymerization under the same conditions and in the same manner as in Example 14, except that trihexylamine was not used and the amounts of each raw material charged were changed to those shown in Table 3. The evaluation results of the obtained polyurethane are shown in Table 3.

[0139] Example 15 A polyurethane solution was obtained by polymerization under the same conditions and in the same manner as in Example 14, except that the amount of trihexylamine was changed to 1 ppm by mass in terms of nitrogen atoms and the amounts of each raw material charged were changed to the amounts shown in Table 3. The evaluation results of the obtained polyurethane are shown in Table 3.

[0140] Example 16 A polyurethane solution was obtained by polymerization under the same conditions and in the same manner as in Example 14, except that the amount of trihexylamine was changed to 3 ppm by mass in terms of nitrogen atoms and the amounts of each raw material charged were changed to the amounts shown in Table 3. The evaluation results of the obtained polyurethane are shown in Table 3.

[0141] Example 17 A polyurethane solution was obtained by polymerization under the same conditions and in the same manner as in Example 14, except that the amount of trihexylamine was changed to 10 ppm by mass in terms of nitrogen atoms and the amounts of each raw material charged were changed to the amounts shown in Table 3. The evaluation results of the obtained polyurethane are shown in Table 3.

[0142] Example 18 Trihexylamine was added to PCD-2 stored in a 0.5 L can to give a concentration of 1 ppm by mass in terms of nitrogen atoms, and phosphoric acid was added to give a concentration of 5 ppm by mass in terms of phosphorus atoms, and the mixture was then heated in an oil bath at 160°C for 6 hours. Thereafter, polyurethane polymerization was carried out under the same conditions and by the same method as in Example 14, except that the amounts of each raw material charged were changed to the amounts shown in Table 3, to obtain a polyurethane solution. The evaluation results for the obtained polyurethane are shown in Table 3.

[0143] Comparative Example 5 A polyurethane solution was obtained by polymerization under the same conditions and in the same manner as in Example 18, except that trihexylamine was not used and the amounts of each raw material charged were changed to those shown in Table 3. The evaluation results of the obtained polyurethane are shown in Table 3.

[0144] Example 19 A polyurethane solution was obtained by polymerization under the same conditions and in the same manner as in Example 18, except that the amount of trihexylamine was changed to 10 ppm by mass in terms of nitrogen atoms and the amounts of each raw material charged were changed to the amounts shown in Table 3. The evaluation results of the obtained polyurethane are shown in Table 3.

[0145] Example 20 A polyurethane solution was obtained by polymerization under the same conditions and in the same manner as in Example 18, except that the amount of trihexylamine was changed to 80 ppm by mass in terms of nitrogen atoms and the amounts of each raw material charged were changed to the amounts shown in Table 3. The evaluation results of the obtained polyurethane are shown in Table 3.

[0146]

[0147] Regarding the evaluation results of the mechanical properties and transparency in Table 3, the evaluation results of mechanical properties such as breaking strength, breaking strength, and elastic modulus, and transparency (YI value) of Examples 14 to 17 and Comparative Example 4 are shown in Figures 4 to 7, respectively. Furthermore, regarding the evaluation results of the mechanical properties test and transparency in Table 3, the evaluation results of mechanical properties such as breaking strength, breaking strength, and elastic modulus, and transparency (YI value) of Examples 18 to 20 and Comparative Example 5 are shown in Figures 8 to 11, respectively.

[0148] The following can be seen from Table 3 and Figures 4 to 11. The polyurethanes obtained in Examples 14 to 17 using PCD-1 as a raw material were excellent in breaking strength, breaking elongation, and elastic modulus, and had low YI values ​​and excellent transparency. In particular, Figures 4 to 6 show that when the content of the nitrogen-containing compound in the polycarbonate diol composition (converted to nitrogen atoms) was around 1 ppm by mass, the polyurethanes were excellent in breaking strength and breaking elongation, had low elastic modulus, and were excellent in flexibility. Furthermore, Figure 7 shows that when a nitrogen-containing compound is present in the polycarbonate diol composition, the YI value of the obtained polyurethane decreases and transparency improves.

[0149] On the other hand, the polyurethane obtained in Comparative Example 4 was inferior in mechanical properties, and the YI value of the obtained polyurethane was large and the transparency was poor because the polycarbonate diol composition used as a raw material did not contain the nitrogen-containing compound.

[0150] The polyurethanes made from PCD-2 obtained in Examples 18 to 20 were excellent in breaking strength, breaking elongation, and elastic modulus, and had low YI values ​​and excellent transparency. In particular, Figures 8 and 10 show that when the content ratio of the nitrogen-containing compound in the polycarbonate diol composition (in terms of nitrogen atoms) was around 1 ppm by mass, the breaking strength was high, the elastic modulus was low, and the flexibility was excellent. Furthermore, Figure 11 shows that when the content ratio (in terms of nitrogen atoms) was around 10 ppm by mass, the YI value was low and the transparency was excellent.

[0151] From the above, it can be seen that the polycarbonate diol composition of the present invention can provide polyurethane with excellent mechanical properties and transparency.

[0152] According to the present invention, a polycarbonate diol composition can be obtained that suppresses the generation of tetrahydrofuran when heated, even when the polycarbonate diol composition is obtained from 1,4-butanediol as a raw material. Polyurethane using the polycarbonate diol composition can reduce silver streaks and foaming caused by the evaporation of tetrahydrofuran, and is excellent in mechanical properties such as breaking strength, breaking elongation, and elastic modulus, as well as transparency, and the present invention provides an industrially extremely useful technology.

Claims

1. A polycarbonate diol composition comprising a polycarbonate diol containing a structural unit (1) represented by the following general formula (I) and a nitrogen-containing compound, wherein the content of the nitrogen-containing compound is 5,000 ppm by mass or less in terms of nitrogen atoms.

2. The polycarbonate diol composition according to claim 1, wherein the content of the nitrogen-containing compound is 0.1 mass ppm or more in terms of nitrogen atoms.

3. The polycarbonate diol composition according to claim 1, wherein the content of the nitrogen-containing compound is 50 mass ppm or less in terms of nitrogen atoms.

4. The polycarbonate diol composition according to claim 1, further comprising a phosphorus atom-containing compound, the content of which is 50 mass ppm or less in terms of phosphorus atoms.

5. The polycarbonate diol composition according to claim 1, wherein the nitrogen-containing compound is an amine-based compound.

6. The polycarbonate diol composition according to claim 1, wherein the nitrogen-containing compound contains one amino group and one or more functional groups, and the functional group includes at least one selected from the group consisting of a hydroxyl group, a carboxyl group, a formyl group, and an amino group.

7. The polycarbonate diol composition according to claim 1, wherein the nitrogen-containing compound contains an amine represented by the following general formula (II-1): (In the above general formula (II-1), R １ represents an alkylene group having 2 to 20 carbon atoms and r substituents X, which may have substituents other than X. X represents a hydroxyl group, a carboxyl group, a formyl group, or an amino group. r is an integer of 1 to 6. R ２ and R ３ each independently represents an alkyl group having 1 to 20 carbon atoms, which may have a substituent, or a hydrogen atom.

8. The polycarbonate diol composition according to claim 1, wherein the number average molecular weight (Mn) of the polycarbonate diol is 250 or more and 5,000 or less.

9. A polyurethane made from the polycarbonate diol composition according to any one of claims 1 to 8 and an isocyanate compound.

10. The polyurethane according to claim 9, which is used in any one selected from the group consisting of active energy radiation-curable polymer compositions, artificial leather, synthetic leather, paints, coating agents, elastic fibers, pressure-sensitive adhesives, and adhesives.

Images