Polycarbonate diol, method for producing polycarbonate diol, polyurethane, and dihydroxy compound-containing composition

Abstract

This polycarbonate diol contains a structural unit (1) represented by general formula (I) and a structural unit (2) represented by general formula (II). The percentage content of the structural unit (2) in the polycarbonate diol is 4.3 mol% or less relative to the total structural units of the polycarbonate diol which is 100 mol%.　The present invention can provide: a method for producing a polycarbonate diol, in which a diol such as 1,4-butanediol is used as a raw material and a polycarbonate diol with a molecular weight close to the theoretical molecular weight in high yield can be obtained; and a polycarbonate diol that makes it possible to obtain a polyurethane having excellent mechanical properties and chemical resistance and configured to suppress variation in the mechanical properties.　In general formula (I), n is an integer of 4-6. Also, in general formula (II), m is an integer of 2-4.

Description

Polycarbonate diol, method for producing polycarbonate diol, polyurethane, and dihydroxy compound-containing composition

[0001] The present invention relates to a polycarbonate diol and a method for producing the polycarbonate diol.Furthermore, the present invention relates to a polyurethane obtained by using the polycarbonate diol.

[0002] The present invention also relates to a dihydroxy compound-containing composition. Furthermore, the present invention also relates to a polycarbonate diol made from the dihydroxy compound-containing composition as a raw material, and a polyurethane made from the polycarbonate diol as a raw material.

[0003] Polycarbonate-type polyurethanes using 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 are considered to have the best durability grade in terms of heat resistance and hydrolysis resistance, and are widely used in durable films, artificial leather for automobiles, paints such as water-based paints, and adhesives. For the above applications, polyurethanes with excellent mechanical properties and reduced variation in mechanical properties are required from the viewpoint of quality uniformity. Furthermore, in recent years, polyurethanes have been required to have properties such as resistance to alcohols contained in hair styling products and resistance to oleic acid, the main component of sebum secreted from the human body.

[0004] To solve these problems, polycarbonate diols containing structural units derived from diols such as 1,4-butanediol have been proposed. Specifically, Patent Document 1 proposes a polycarbonate diol copolymerized from 1,4-butanediol and 1,5-pentanediol as raw materials, and a method for producing the same. Furthermore, Patent Document 2 proposes a polycarbonate diol copolymerized from 1,4-butanediol and 1,6-hexanediol as raw materials, and a method for producing the same.

[0005] Furthermore, in order to obtain polyurethanes having an excellent balance of physical properties such as flexibility, chemical resistance, and hydrolysis resistance, a polyester carbonate diol containing structural units derived from 1,4-butanediol and dicarboxylic acid and a method for producing the same are proposed in Patent Documents 3 and 4. Furthermore, Patent Document 5 proposes a method for producing a polycarbonate diol with excellent industrial productivity, in which when producing a polycarbonate diol containing structural units derived from 1,4-butanediol, the content of acid components such as dicarboxylic acid contained in the raw material diol is controlled to a predetermined value or less, thereby reducing the by-production of tetrahydrofuran.

[0006] Japanese Patent Application Laid-Open No. 04-007327 International Publication No. 2009 / 063767 Japanese Patent Application Laid-Open No. 2022-137002 International Publication No. 2023 / 080134 Japanese Patent Application Laid-Open No. 2018-197358

[0007] "Fundamentals and Applications of Polyurethanes" pp. 96-106, edited by Katsuji Matsunaga, CMC Publishing Co., Ltd., published November 2006

[0008] However, the polycarbonate diol production methods described in Patent Documents 1 to 5 had insufficient yields of polycarbonate diol. Furthermore, the polycarbonate diols obtained by the production methods described in Patent Documents 1 to 5 had molecular weights higher than the theoretical molecular weight, resulting in a problem of reduced mechanical properties of the resulting polyurethane. Furthermore, Patent Documents 1 to 5 do not disclose or suggest that, in polyurethanes obtained using polycarbonate diols made from diols such as 1,4-butanediol as a raw material, the dicarboxylic acid or dicarboxylic acid derivative contained in the diol improves the mechanical properties and chemical resistance of the polyurethane, or further reduces the variation in mechanical strength. Therefore, until now, fully satisfactory results have not been obtained in terms of quality when industrially producing and using polyurethanes using polycarbonate diols made from diols such as 1,4-butanediol as a raw material.

[0009] The present invention has been made in view of the above-mentioned problems. Specifically, the present invention relates to a polycarbonate diol obtained using a diol such as 1,4-butanediol as a raw material, and a polyurethane obtained using the polycarbonate diol has excellent mechanical properties and chemical resistance, with reduced variation in the mechanical properties. An object of the present invention is to provide a polycarbonate diol that can provide a polyurethane with such excellent performance. Furthermore, the present invention makes it possible to obtain a polycarbonate diol having a molecular weight close to the theoretical molecular weight in high yield, and the polyurethane obtained using the polycarbonate diol has excellent mechanical properties and chemical resistance, with reduced variation in the mechanical properties. An object of the present invention is to provide a method for producing a polycarbonate diol that can provide a polyurethane with such excellent performance.

[0010] Another object of the present invention is to provide a dihydroxy compound-containing composition that contains a dihydroxy compound such as 1,4-butanediol, and that can produce a polycarbonate diol having a molecular weight close to the theoretical molecular weight in high yield.

[0011] As a result of intensive research to solve the above problems, the present inventors have found that the above problems can be solved by producing a polycarbonate diol using a diol such as 1,4-butanediol and a specific dicarboxylic acid or dicarboxylic acid derivative as raw materials.

[0012] That is, the present invention is summarized as follows.

[0013] [1] A polycarbonate diol containing a structural unit (1) represented by the following general formula (I) and a structural unit (2) represented by the following general formula (II), wherein the content of the structural unit (2) in the polycarbonate diol is 4.3 mol % or less relative to 100 mol % of all structural units in the polycarbonate diol.

[0014]

[0015] (In the above general formula (I), n is an integer of 4 to 6.)

[0016]

[0017] (In the above general formula (II), m is an integer of 2 to 4.)

[0018] [2] The polycarbonate diol according to [1] above, wherein the content of the structural unit (2) in the polycarbonate diol is 3.0 mol% or less, relative to 100 mol% of all structural units in the polycarbonate diol. [3] The polycarbonate diol according to [1] or [2] above, wherein the structural unit (1) represented by general formula (I) includes a structural unit derived from a biomass-derived dihydroxy compound. [4] The polycarbonate diol according to any one of [1] to [3] above, wherein the structural unit (1) represented by general formula (I) is derived from a biomass-derived dihydroxy compound alone or a mixture containing a biomass-derived dihydroxy compound and a fossil fuel-derived dihydroxy compound. [5] The polycarbonate diol according to [3] or [4] above, wherein the biomass-derived dihydroxy compound is a compound derived from non-edible biomass and / or non-fossil fuel. [6] The polycarbonate diol according to any one of [1] to [5], wherein the number average molecular weight (Mn) of the polycarbonate diol is 250 or more and 5000 or less. [7] A method for producing a polycarbonate diol, comprising transesterifying a dihydroxy compound-containing composition containing a compound (1-1) represented by the following general formula (I-1) and a compound (2-1) represented by the following general formula (II-1) with a carbonate compound in the presence of a catalyst to obtain a polycarbonate diol, wherein the content of the compound (2-1) in the dihydroxy compound-containing composition is 5.3 mass% or less, relative to 100% by mass of the total mass of the dihydroxy compound-containing composition.

[0019]

[0020] (In the above general formula (I-1), n ​​is an integer of 4 to 6.)

[0021]

[0022] (In the above general formula (II-1), m is an integer of 2 to 4. R １ represents a hydrogen atom, a heteroatom, or an alkyl group having 2 to 20 carbon atoms which may have a heteroatom or a substituent. １ may be the same or different.)

[0023] [8] In the compound (2-1), R １ [9] The method for producing a polycarbonate diol according to the above [7] or [8], wherein the catalyst contains a titanium atom and the amount of the catalyst is 50 ppm by mass or less in terms of titanium atoms relative to the total mass of the dihydroxy compound-containing composition.

[0024]

[10] A polyurethane made from the polycarbonate diol described in any one of [1] to [6] above and an isocyanate compound.

[11] The polyurethane described in

[10] above is used in any one selected from the group consisting of an active-energy radiation-curable polymer composition, artificial leather, synthetic leather, paint, coating agent, elastic fiber, pressure-sensitive adhesive, and adhesive.

[0025]

[12] A dihydroxy compound-containing composition comprising a compound (1-1) represented by the following general formula (I-1) and a compound (2-1) represented by the following general formula (II-1), wherein the content of the compound (2-1) in the dihydroxy compound-containing composition is 5.3 mass% or less, relative to 100% by total mass of the dihydroxy compound-containing composition.

[0026]

[0027] (In the above general formula (I-1), n ​​is an integer of 4 to 6.)

[0028]

[0029] (In the above general formula (II-1), m is an integer of 2 to 4. R １represents a hydrogen atom, a heteroatom, or an alkyl group having 2 to 20 carbon atoms which may have a heteroatom or a substituent. １ may be the same or different.)

[0030]

[13] The dihydroxy compound-containing composition according to the above

[12] , wherein the content of the compound (1-1) in the dihydroxy compound-containing composition is 40.0 mass% or more relative to 100% of the total mass of the dihydroxy compound-containing composition.

[14] In the compound (2-1), R １

[15] The dihydroxy compound-containing composition according to any one of

[12] to

[14] above, wherein at least one of R is an alkyl group having 2 to 20 carbon atoms, which may have a heteroatom or a substituent.

[16] The dihydroxy compound-containing composition according to any one of

[12] to

[14] above, wherein the compound (1-1) contains 1,4-butanediol.

[17] In the compound (2-1), R １ wherein at least one of the above is an alkyl group having 4 carbon atoms, which may have a heteroatom or a substituent.

[17] The dihydroxy compound-containing composition according to any of the above

[12] to

[16] , wherein the compound (I-1) comprises a diol derived from biomass.

[18] The dihydroxy compound-containing composition according to any of the above

[12] to

[17] , which is used in a process for producing a polycarbonate diol.

[0031]

[19] A polycarbonate diol made from the dihydroxy compound-containing composition according to any one of

[12] to

[18] above and a carbonate compound.

[20] A polyurethane made from the polycarbonate diol according to

[19] above and an isocyanate compound.

[0032] According to the present invention, there is provided a polycarbonate diol obtained from a diol such as 1,4-butanediol as a raw material, which can be used to obtain a polyurethane having excellent mechanical properties and chemical resistance and with reduced variation in the mechanical properties.Furthermore, the present invention can provide a method for producing a polycarbonate diol that can obtain a polycarbonate diol having a molecular weight close to the theoretical molecular weight in high yield, and can be used to obtain a polyurethane having excellent mechanical properties and chemical resistance and with reduced variation in the mechanical properties.

[0033] Furthermore, according to the present invention, there can be provided a dihydroxy compound-containing composition that can be used to produce a polycarbonate diol having a molecular weight close to the theoretical molecular weight.Furthermore, according to the present invention, there can be provided a polycarbonate diol that is made from the dihydroxy compound-containing composition as a raw material, and that can produce a polyurethane that is excellent in mechanical properties and chemical resistance and has reduced variations in the mechanical properties.

[0034] 1 is a graph showing the relationship between the content of compound (2-1) in dihydroxy compound-containing compositions and the molecular weight (M(PCD)) of the polycarbonate diol obtained in Examples and Comparative Examples. 2 is a graph showing the relationship between the content of compound (2-1) in dihydroxy compound-containing compositions and the yield of polycarbonate diol obtained in Examples and Comparative Examples. 3 is a graph showing the relationship between the content of structural unit (2) in polycarbonate diol and the molecular weight (M(PCD)) of the polycarbonate diol obtained in Examples and Comparative Examples. 4 is a graph showing the relationship between the content of structural unit (2) in polycarbonate diols obtained in Examples and Comparative Examples and the breaking strength of polyurethanes obtained using the polycarbonate diols. 5 is a graph showing the relationship between the content of structural unit (2) in polycarbonate diols obtained in Examples and Comparative Examples and the 100% modulus of polyurethanes obtained using the polycarbonate diols. 1 is a graph showing the relationship between the content of the structural unit (2) in the polycarbonate diols obtained in the Examples and Comparative Examples and the 300% modulus of the polyurethanes obtained using the polycarbonate diols. 2 is a graph showing the relationship between the content of the structural unit (2) in the polycarbonate diols obtained in the Examples and Comparative Examples and the coefficient of variation of the breaking strength of the polyurethanes obtained using the polycarbonate diols. 3 is a graph showing the relationship between the content of the structural unit (2) in the polycarbonate diols obtained in the Examples and Comparative Examples and the coefficient of variation of the 100% modulus of the polyurethanes obtained using the polycarbonate diols. 4 is a graph showing the relationship between the content of the structural unit (2) in the polycarbonate diols obtained in the Examples and Comparative Examples and the coefficient of variation of the 300% modulus of the polyurethanes obtained using the polycarbonate diols. 5 is a graph showing the relationship between the content of the structural unit (2) in the polycarbonate diols obtained in the Examples and Comparative Examples and the mass change rate (increase rate) obtained in an oleic acid resistance test for the polyurethanes obtained using the polycarbonate diols. FIG. 1 is a graph showing the relationship between the content of structural unit (2) in polycarbonate diols obtained in Examples and Comparative Examples and the mass change rate (increase rate) of polyurethanes obtained using the polycarbonate diols in an ethanol resistance test.FIG. 1 is a graph showing the relationship between the content of structural unit (2) in polycarbonate diols obtained in Examples and Comparative Examples and the breaking strength retention rate obtained in a hydrolysis resistance test of polyurethanes obtained using the polycarbonate diols.

[0035] 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.

[0036] In this specification, "A or B" means "A," "B," and "A and B," unless otherwise specified. For example, "containing A or B" means "containing A," "containing B," and "containing A and B," unless otherwise specified. 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, simply referring to "ppm" means "weight ppm."

[0037] 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".

[0038] As used herein, "optional" or "optionally" means that the subsequently described circumstance may or may not occur, and thus the description includes both the occurrence and non-occurrence of the circumstance.

[0039] As used herein, the term "about" can mean above and below 20% of the stated value. For example, about 75°C encompasses the range of 60°C to 90°C.

[0040] In this specification, the term "obtained polyurethane" refers to a polyurethane obtained using the polycarbonate diol of the present invention and an isocyanate compound as raw materials.

[0041] In this specification, "the polycarbonate diol of the present invention," "the method for producing the polycarbonate diol of the present invention," "the dihydroxy compound-containing composition of the present invention," and "the polyurethane of the present invention" are collectively referred to as "the present invention."

[0042] All steps described herein can be performed in any suitable order unless otherwise stated herein or clearly contradicted by context.

[0043] <Polycarbonate diol> The polycarbonate diol of the present invention is a polycarbonate diol containing a structural unit (1) represented by the following general formula (I) and a structural unit (2) represented by the following general formula (II) (hereinafter, this may be referred to as the "polycarbonate diol of the present invention.") Details of the structural unit (1) and the structural unit (2) will be described later.

[0044]

[0045] (In the above general formula (I), n is an integer of 4 to 6.)

[0046]

[0047] (In the above general formula (II), m is an integer of 2 to 4.)

[0048] Furthermore, in the polycarbonate diol of the present invention, the content of the structural unit (2) in the polycarbonate diol is 4.3 mol % or less relative to 100 mol % of all structural units in the polycarbonate diol.

[0049] The polycarbonate diol of the present invention contains the structural unit (1), and thus the polyurethane obtained using this polycarbonate diol has good mechanical strength and chemical resistance.

[0050] The polycarbonate diol of the present invention contains the structural unit (2), and thus the polyurethane obtained using this polycarbonate diol has excellent mechanical properties and chemical resistance, and the variations in the mechanical properties are suppressed.

[0051] Furthermore, the polycarbonate diol of the present invention may contain, as necessary, a structural unit (3) derived from a hydroxy group-containing compound (3-1) other than the compound (1-1) described below and the compound (2-1) described below, within a range that does not impair the effects of the present invention.

[0052] (Molecular Weight of Polycarbonate Diol) The lower limit of the number average molecular weight (Mn) of the polycarbonate diol of 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 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 of 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.

[0053] 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 In this case, the hydroxyl value can be measured by a known method using an acetylating reagent in accordance with JIS K1557-1.

[0054] (Metal Atom Content of Polycarbonate Diol Composition) In the method for producing a polycarbonate diol of the present invention, the catalyst used in producing the polycarbonate diol may remain. In this way, a polycarbonate diol containing a metal derived from the catalyst may be referred to as a polycarbonate diol composition. As described later, this catalyst is preferably a catalyst containing a titanium atom. Therefore, the polycarbonate diol composition of the present invention contains a metal atom such as a titanium atom derived from the catalyst.

[0055] In the method for producing a polycarbonate diol of the present invention, the content of metal atoms such as titanium atoms in the polycarbonate diol composition is preferably 50 mass ppm or less, more preferably 40 mass ppm or less, even more preferably 30 mass ppm or less, and particularly preferably 20 mass ppm or less, relative to the total mass of the polycarbonate diol composition of the present invention. If the content of metal atoms in the polycarbonate diol composition of the present invention exceeds the upper limit, problems such as coloration of the polycarbonate diol composition and reaction inhibition when producing polyurethane using this polycarbonate diol composition occur, which is undesirable. On the other hand, in order to reduce the content of metal atoms in the polycarbonate diol composition of the present invention, it is necessary to reduce the amount of catalyst used in the production stage of the polycarbonate diol composition of the present invention. However, reducing the amount of catalyst reduces the polymerization reaction efficiency and requires the obtained polycarbonate diol composition to be highly purified, which is undesirable in terms of production efficiency. From this viewpoint, the content of metal atoms in the polycarbonate diol composition of the present invention is preferably 1 mass ppm or more, more preferably 2 mass ppm or more, even more preferably 3 mass ppm or more, and particularly preferably 4 mass ppm or more. The upper and lower limits can be arbitrarily combined. For example, the content of metal atoms such as titanium atoms in the polycarbonate diol composition of the present invention is preferably 1 mass ppm or more and 50 mass ppm or less, more preferably 2 mass ppm or more and 40 mass ppm or less, still more preferably 3 mass ppm or more and 30 mass ppm or less, and particularly preferably 4 mass ppm or more and 20 mass ppm or less, relative to the total mass of the polycarbonate diol composition.

[0056] In the method for producing a polycarbonate diol of the present invention, by using the compound (2-1) together with the compound (1-1) described below, a polycarbonate diol can be efficiently produced with a relatively small amount of catalyst, and the amount of residual metal atoms in the polycarbonate diol can be reduced.

[0057]

[0033] The polycarbonate diol of the present invention contains metal atoms as described above, and is therefore also called a "polycarbonate diol composition" rather than a "polycarbonate diol." However, the metal atom content is extremely small, usually in the ppm by mass range, and is a trace component at the level of being contained as an impurity in general industrial products, so those skilled in the art would call it a "polycarbonate diol." Therefore, in the examples described below, the polycarbonate diol containing metal atoms is simply called a "polycarbonate diol," and the metal atom content in the polycarbonate diol is measured and evaluated.

[0058] (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.

[0059]

[0060] (In the above general formula (I), n is an integer of 4 to 6.)

[0061] In the general formula (I), n is an integer of 4 to 6, preferably 4 or 6, and more preferably 4, from the viewpoint of improving the mechanical properties and chemical resistance of the resulting polyurethane. The structural unit (1) may be used alone or in combination of two or more types.

[0062] The lower limit of the content of the structural unit (1) in the polycarbonate diol of the present invention is not particularly limited, and from the viewpoint of obtaining 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, and from the viewpoint of maintaining good mechanical properties and chemical resistance of the resulting polyurethane, it is preferably less than 100 mol%, more preferably 99.999 mol% or less, even more preferably 99.998 mol% or less, and particularly preferably 99.997 mol% or less, 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 (1) in the polycarbonate diol of the present invention is preferably 20 mol% or more and less than 100 mol%, more preferably 40 mol% or more and 99.999 mol% or less, still more preferably 50 mol% or more and 99.998 mol% or less, and particularly preferably 60 mol% or more and 99.997 mol% or less, relative to 100 mol% of the structural units of the polycarbonate diol.

[0063] In the polycarbonate diol of the present invention, the structural unit (1) preferably contains a structural unit (1b) represented by the following formula (Ib), from the viewpoint of improving the mechanical properties and chemical resistance of the obtained polyurethane.

[0064]

[0065] In the polycarbonate diol of the present invention, the structural unit (1b) represented by the formula (Ib) can be a compound represented by the following formula (Ib-1), that is, a structural unit derived from 1,4-butanediol.

[0066]

[0067] The lower limit of the content of the structural unit (1b) in the polycarbonate diol of the present invention is not particularly limited, and from the viewpoint of obtaining 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 (1b) is not particularly limited, and from the viewpoint of maintaining good mechanical properties and chemical resistance of the resulting polyurethane, it is preferably less than 100 mol%, more preferably 99.999 mol% or less, even more preferably 99.998 mol% or less, and particularly preferably 99.997 mol% or less, 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 (1b) in the polycarbonate diol of the present invention is preferably 20 mol% or more and less than 100 mol%, more preferably 40 mol% or more and 99.999 mol% or less, still more preferably 50 mol% or more and 99.998 mol% or less, and particularly preferably 60 mol% or more and 99.997 mol% or less, relative to 100 mol% of the structural units of the polycarbonate diol.

[0068] In the polycarbonate diol of the present invention, the specific method for controlling the content ratio of the structural unit (1) 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 production method of the polycarbonate diol of the present invention described later based on well-known techniques.

[0069] In order to introduce the structural unit (1) represented by the general formula (I) into the polycarbonate diol of the present invention, a structural unit derived from a dihydroxy compound (1-1) (also simply referred to as "compound (1-1)" in this specification) represented by the following general formula (I-1) can be used.

[0070]

[0071] (In the above general formula (I-1), n ​​is an integer of 4 to 6.)

[0072] In the general formula (I-1), n ​​has the same meaning as n in the general formula (I), and from the viewpoint of improving the mechanical properties and chemical resistance of the obtained polyurethane, n is an integer of 4 to 6, preferably 4 or 6, and more preferably 4.

[0073] The compound represented by the formula (I-1) is not particularly limited, and known dihydroxy compounds used as raw materials for polycarbonate diols can be appropriately selected and used. Examples of the compound (1-1) represented by the formula (I-1) include 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol. From the viewpoint of excellent durability such as chemical resistance, 1,4-butanediol and 1,6-hexanediol are preferred, and 1,4-butanediol (n=4 in the general formula (I-1)) is particularly preferred. The compound (1-1) can be appropriately selected by those skilled in the art depending on the use and production conditions of the polycarbonate diol, etc. Furthermore, these compounds may be used alone or in combination of two or more.

[0074] The polycarbonate diol of the present invention can achieve the Sustainable Development Goals (SDGs) by using a biomass-derived compound (1-1) as the compound (1-1). Specifically, a biomass-derived diol alone or a mixture containing a biomass-derived diol and a fossil fuel-derived diol can be used. The biomass-derived compound (1-1) is a compound (1-1) derived from non-edible biomass and / or non-fossil fuel.

[0075] 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.

[0076] In the present invention, the compound (1-1) derived from a fossil fuel refers to at least one selected from the group consisting of a compound (1-1) derived from petroleum, a compound (1-1) derived from coal, and a compound (1-1) derived from natural gas.

[0077] The above-mentioned biomass-derived compound (1-1) may contain the compound (2-1) from which the above-mentioned structural unit (2) is derived, depending on its origin. Therefore, the effects of the present invention described above can be obtained by producing a polycarbonate diol by controlling the content ratio of the compound (2-1) in the compound (1-1) or by controlling the content ratio of the structural unit (2) in a polycarbonate diol obtained using the compound (1-1) as a raw material.

[0078] For example, the polycarbonate diol of the present invention can use fossil fuel-derived 1,4-butanediol alone as compound (1-1) from which the structural unit (1) is derived. The polycarbonate diol of the present invention can achieve the Sustainable Development Goals (SDGs) by using, as compound (1-1), 1,4-butanediol including biomass-derived 1,4-butanediol, specifically biomass-derived 1,4-butanediol alone, or a mixture containing biomass-derived 1,4-butanediol and fossil fuel-derived 1,4-butanediol. Biomass-derived 1,4-butanediol is 1,4-butanediol derived from non-edible biomass and / or non-fossil fuel.

[0079] 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.

[0080] The above-mentioned biomass-derived 1,4-butanediol may contain the above-mentioned compound (2-1) depending on its origin. Therefore, the effects of the present invention can be obtained by producing a polycarbonate diol by controlling the content ratio of the compound (2-1) in the 1,4-butanediol, or by controlling the content ratio of the structural unit (2) in a polycarbonate diol obtained using the 1,4-butanediol as a raw material.

[0081] (Structural Unit (2)) The above-mentioned structural unit (2) is a structural unit represented by the following general formula (II) contained in the structure of the polycarbonate diol of the present invention.

[0082]

[0083] (In the above general formula (II), m is an integer of 2 to 4.)

[0084] In the general formula (II), m is an integer of 2 to 4. From the viewpoint of improving the mechanical properties of the resulting polyurethane, m is preferably 2 or 4, and more preferably 2. The structural unit (2) may be used alone or in combination of two or more types.

[0085] The upper limit of the content of the structural unit (2) in the polycarbonate diol is usually 4.3 mol% or less, preferably 3.0 mol% or less, more preferably 0.9 mol% or less, even more preferably 0.8 mol% or less, particularly preferably 0.7 mol% or less, and most preferably 0.5 mol% or less, relative to 100 mol% of the structural units of the polycarbonate diol, from the viewpoint that the mechanical properties and durability such as chemical resistance and hydrolysis resistance of the obtained polyurethane can be expected to be maintained well. On the other hand, the lower limit of the content of the structural unit (2) is not particularly limited, and from the viewpoint of the obtained polyurethane having excellent mechanical properties and chemical resistance and suppressing variation in the mechanical properties, it can be set to 0.0001 mol% or more, preferably 0.0005 mol% or more, more preferably 0.001 mol% or more, even more preferably 0.002 mol% or more, particularly preferably 0.003 mol% or more, and most preferably 0.005 mol% or more, relative to 100 mol% of the structural unit of the polycarbonate diol. The above upper and lower limits can be arbitrarily combined. For example, the content of the structural unit (2) in the polycarbonate diol of the present invention can be 0.0001 mol% or more and 4.3 mol% or less, preferably 0.0005 mol% or more and 3.0 mol% or less, more preferably 0.001 mol% or more and 0.9 mol% or less, even more preferably 0.002 mol% or more and 0.8 mol% or less, particularly preferably 0.003 mol% or more and 0.7 mol% or less, and most preferably 0.005 mol% or more and 0.5 mol% or less, relative to 100 mol% of the structural units of the polycarbonate diol.

[0086] 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. For example, when using sugar or the like as a biomass resource as a raw material and fermenting it with a bacterial cell to obtain the compound (1-1), a compound (2-1) such as a dicarboxylic acid or a dicarboxylic acid derivative, which will be described later, is by-produced, and this can be controlled by adjusting the type of bacterial cell, the fermentation time, the distillation purification conditions, etc. As for other methods, a person skilled in this field can control the content ratio by appropriately optimizing the production conditions of the method for producing the polycarbonate diol of the present invention, which will be described later, based on well-known techniques.

[0087] In the polycarbonate diol of the present invention, as the structural unit represented by the general formula (II), a structural unit derived from a compound (2-1) represented by the following general formula (II-1) can be used.

[0088]

[0089] (In the above general formula (II-1), m is an integer of 2 to 4. R １ represents a hydrogen atom, a heteroatom, or an alkyl group having 2 to 20 carbon atoms which may have a heteroatom or a substituent. １ may be the same or different.)

[0090] In the general formula (II-1), m has the same meaning as m in the general formula (II), and is an integer of 2 to 4. From the viewpoint of improving the mechanical properties of the obtained polyurethane, m is preferably 2 or 4, and more preferably 2.

[0091] R in the general formula (II-1) １ is a hydrogen atom, a heteroatom, or an alkyl group having 2 to 20 carbon atoms which may have a heteroatom or a substituent. １When at least one of R is a hetero atom, the compound (2-1) becomes a carboxylate. In such a case, the hetero atom is not particularly limited, and lithium, sodium, and potassium are preferred from the viewpoint of improving the solubility of the compound (2-1) in a solution when producing the polycarbonate diol of the present invention. １ In the case where at least one of the above is an alkyl group having 2 to 20 carbon atoms which may have a heteroatom or a substituent, the compound (2-1) becomes a carboxylic acid ester. The alkyl group having 2 to 20 carbon atoms is not particularly limited, and from the viewpoint of improving the solubility of the compound (2-1) in a solution when producing the polycarbonate diol of the present invention, the alkyl group preferably has 3 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, and even more preferably 4 to 6 carbon atoms, and is particularly preferably an alkyl group having 4 to 6 carbon atoms and containing an oxygen atom.

[0092] In the general formula (II-1), R １ From the viewpoint of obtaining a polycarbonate diol having a molecular weight close to the theoretical molecular weight in high yield, at least one of R is preferably an alkyl group having 2 to 20 carbon atoms which may have a heteroatom or a substituent, and more preferably an alkyl group having 4 carbon atoms which may have a heteroatom or a substituent. １ Specific examples of the alkyl group having 2 to 20 carbon atoms include an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a hydroxybutyl group, a pentyl group, a hexyl group, a hydroxyhexyl group, an octyl group, a decyl group, a hydroxydecyl group, a dodecyl group, an octadecyl group, and an eicosyl group.

[0093] The compound (2-1) is not particularly limited, and examples thereof include known dicarboxylic acids, known dicarboxylic acid salts, and known dicarboxylic acid esters. Among these, from the viewpoints of inhibiting coloration of the polycarbonate diol and solubility, carboxylic acids or carboxylic acid esters are preferred. From the viewpoint of polymerization stability during the production of the polycarbonate diol, carboxylic acid esters are more preferred.

[0094] Examples of the compound (2-1) include precursor compounds of the compound (1-1). For example, the compound (2-1) includes at least one selected from the group consisting of dicarboxylic acids, dicarboxylates, and dicarboxylate esters having 4 to 6 carbon atoms, which are precursor compounds of the compound (1-1). More specifically, examples of the compound (2-1) include precursors of the compound (1-1) represented by the general formula (I-1), such as succinic acid, succinate, and succinate esters when n = 4; glutaric acid, glutarate, and glutarate esters when n = 5; and adipic acid, adipate, and adipate esters when n = 6. These compounds may be used alone or in combination of two or more.

[0095] (Structural Unit (3)) As described above, the polycarbonate diol of the present invention can contain, as necessary, the structural unit (3) derived from a hydroxy group-containing compound (3-1) other than the compound (1-1) and the compound (2-1), within a range that does not impair the effects of the present invention. Specific examples of the dihydroxy compound (3-1) include linear diols such as 1,3-propanediol, 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-1,3-propanediol. diols having a side chain such as 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.

[0096] The upper limit of the content of the structural unit (3) in the polycarbonate diol is preferably 70 mol% or less, more preferably 50 mol% or less, even more preferably 40 mol% or less, and particularly preferably 30 mol% or more, relative to 100 mol% of the structural units of the polycarbonate diol, from the viewpoint of maintaining good mechanical properties and chemical resistance of the polyurethane obtained using the polycarbonate diol as a raw material. On the other hand, the lower limit of the content of the structural unit (3) is not particularly limited, and from the viewpoint of maintaining good mechanical properties of the polyurethane obtained using the polycarbonate diol as a raw material, it is preferably 1 mol% or more, more preferably 2 mol% or more, even more preferably 3 mol% or more, and particularly preferably 4 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 (3) in the polycarbonate diol of the present invention is preferably 1 mol% or more and 70 mol% or less, more preferably 2 mol% or more and 50 mol% or less, even more preferably 3 mol% or more and 40 mol% or less, and particularly preferably 4 mol% or more and 30 mol% or less, relative to 100 mol% of the structural units of the polycarbonate diol.

[0097] In the polycarbonate diol of the present invention, the specific method for controlling the content ratio of the structural unit (3) 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 production method of the polycarbonate diol of the present invention described below based on well-known techniques.

[0098] When the polycarbonate diol of the present invention contains the structural unit (3), the content of compound (1-1) in the dihydroxy compound-containing composition described below, which is used as a raw material for producing the polycarbonate diol of the present invention, is not particularly limited, and from the viewpoint of improving the handleability of the polycarbonate diol and the mechanical properties and durability of the resulting polyurethane, it is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 40% by mass or more, and particularly preferably 50% by mass or more, relative to 100% by total mass of the dihydroxy compound-containing composition. On the other hand, the upper limit of the content of compound (1-1) in the dihydroxy compound-containing composition is not particularly limited, and is preferably less than 100% by mass, more preferably 98% by mass or less, even more preferably 95% by mass or less, and particularly preferably 90% by mass or less, relative to 100% by total mass of the dihydroxy compound-containing composition. The above upper and lower limits can be combined arbitrarily. For example, the content of compound (1-1) in the dihydroxy compound-containing composition of the present invention is preferably 5% by mass or more and less than 100% by mass, more preferably 10% by mass or more and 98% by mass or less, still more preferably 40% by mass or more and 95% by mass or less, and particularly preferably 50% by mass or more and 90% by mass or less, relative to 100% by mass of the total mass of the dihydroxy compound-containing composition.

[0099] <Dihydroxy Compound-Containing Composition> The dihydroxy compound-containing composition of the present invention is a composition containing a compound (1-1) represented by the following general formula (I-1) and a compound (2-1) represented by the following general formula (II-1).

[0100]

[0101] (In the above general formula (I-1), n ​​is an integer of 4 to 6.)

[0102]

[0103] (In the above general formula (II-1), m is an integer of 2 to 4. R １ represents a hydrogen atom, a heteroatom, or an alkyl group having 2 to 20 carbon atoms which may have a heteroatom or a substituent. １may be the same or different.)

[0104] In the dihydroxy compound-containing composition of the present invention, the compound (1-1) and the compound (2-1) are treated as having the same meaning as the compound (1-1) and the compound (2-1) described in the description of the polycarbonate diol of the present invention, respectively.

[0105] In the present invention, the upper limit of the content of compound (2-1) in the dihydroxy compound-containing composition is 5.3% by mass or less, preferably 4.0% by mass or less, more preferably 3.2% by mass or less, even more preferably 2.5% by mass or less, still more preferably 1.5% by mass or less, particularly preferably 1.0% by mass or less, and most preferably 0.5% by mass or less, relative to 100% by mass of the total mass of the dihydroxy compound-containing composition, from the viewpoints of facilitating molecular weight control during polymerization of the polycarbonate diol and of improving the mechanical properties and chemical resistance of the polyurethane obtained from the polycarbonate diol. On the other hand, the lower limit of the content of the compound (2-1) is not particularly limited, and from the viewpoint of obtaining a polycarbonate diol having a molecular weight close to the theoretical molecular weight in high yield, it can usually be set to 0.0001% by mass or more, preferably 0.001% by mass or more, more preferably 0.002% by mass or more, even more preferably 0.003% by mass or more, still more preferably 0.005% by mass or more, particularly preferably 0.007% by mass or more, and most preferably 0.010% by mass or more, relative to 100% by mass of the total mass of the dihydroxy compound-containing composition. The above upper and lower limits can be arbitrarily combined. For example, in the present invention, the content of compound (2-1) in the dihydroxy compound-containing composition can be 0.0001% by mass or more and 5.3% by mass or less, preferably 0.001% by mass or more and 4.0% by mass or less, more preferably 0.002% by mass or more and 3.2% by mass or less, even more preferably 0.003% by mass or more and 2.5% by mass or less, still more preferably 0.005% by mass or more and 1.5% by mass or less, particularly preferably 0.007% by mass or more and 1.0% by mass or less, and most preferably 0.010% by mass or more and 0.5% by mass or less, relative to 100% by mass of the total mass of the dihydroxy compound-containing composition.

[0106] The method for adjusting the content ratio of the compound (2-1) in the dihydroxy compound-containing composition is not particularly limited, and can be controlled, for example, by adjusting the conversion rate of the carboxylic acid or carboxylic acid ester in the hydrogenation reaction step when the compound (1-1) is obtained by the hydrogenation reaction of a carboxylic acid or a carboxylic acid ester.

[0107] For example, methods for reducing the content of compound (2-1) in the production stage of the dihydroxy compound-containing composition include increasing the amount of catalyst used in the hydrogenation reaction, lengthening the residence time, increasing the hydrogen pressure, etc., thereby increasing the conversion rate, and thus the content of compound (2-1) in the resulting dihydroxy compound-containing composition decreases. On the other hand, methods for increasing the content of compound (2-1) in the production stage of the dihydroxy compound-containing composition include decreasing the amount of catalyst used in the hydrogenation reaction, shortening the residence time, lowering the hydrogen pressure, etc., thereby increasing the content of compound (2-1).

[0108] In order to reduce the content of compound (2-1) to less than 0.0001 mass% in the production stage of the dihydroxy compound-containing composition, methods such as increasing the amount of catalyst used in the hydrogenation reaction of carboxylic acid or carboxylic acid ester, which are raw materials for the dihydroxy compound, lengthening the residence time, or excessively increasing the hydrogen pressure can be used; however, these methods impose a large burden on the production stage and are not easy to do.

[0109] When the compound (1-1) is 1,4-butanediol (compound (1-1), n ​​= 4) and is derived from biomass, the 1,4-butanediol may contain, as compound (2-1), the above-mentioned carboxylic acids such as succinic acid, carboxylates such as sodium succinate, and carboxylate esters such as bis(4-hydroxybutyl)succinic acid and mono(4-hydroxybutyl)succinic acid.

[0110] In the present invention, the lower limit of the content of compound (1-1) in the dihydroxy compound-containing composition is preferably 40.0 mass% or more, more preferably 50.0 mass% or more, even more preferably 60.0 mass% or more, particularly preferably 80.0 mass% or more, and most preferably 90.0 mass% or more, relative to 100% by total mass of the dihydroxy compound-containing composition, from the viewpoints of facilitating molecular weight control during polymerization of polycarbonate diol and of improving the mechanical properties and chemical resistance of polyurethane obtained from the polycarbonate diol. The content of compound (1-1) in the dihydroxy compound-containing composition may be the total amount excluding compound (2-1) contained in the dihydroxy compound-containing composition. On the other hand, the upper limit of the content of the compound (1-1) is not particularly limited, and from the viewpoint of obtaining a polycarbonate diol having a molecular weight close to the theoretical molecular weight in high yield, it is usually preferably 99.999% by mass or less, more preferably 99.998% by mass or less, even more preferably 99.995% by mass or less, particularly preferably 99.993% by mass or less, and most preferably 99.990% by mass or less, based on 100% by total mass of the dihydroxy compound-containing composition. The above upper and lower limits can be combined arbitrarily. For example, in the present invention, the content of compound (1-1) in the dihydroxy compound-containing composition is preferably 40.0% by mass or more and 99.999% by mass or less, more preferably 50.0% by mass or more and 99.998% by mass or less, even more preferably 60.0% by mass or more and 99.995% by mass or less, particularly preferably 80.0% by mass or more and 99.993% by mass or less, and most preferably 90.0% by mass or more and 99.990% by mass or less, relative to 100% by mass of the total mass of the dihydroxy compound-containing composition.

[0111] <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. As a preferred embodiment of the method for producing the polycarbonate diol of the present invention, the method for producing the polycarbonate diol of the present invention will be described below.

[0112] The method for producing a polycarbonate diol of the present invention comprises polycondensing the dihydroxy compound-containing composition of the present invention described above, specifically the dihydroxy compound-containing composition containing compound (1-1) represented by general formula (I-1) and compound (2-1) represented by general formula (II-1), with a carbonate compound via transesterification in the presence of a catalyst to obtain a polycarbonate diol. Furthermore, in the method for producing a polycarbonate diol of the present invention, the content of compound (2-1) in the dihydroxy compound-containing composition is 5.3 mass% or less, relative to the total mass of the dihydroxy compound-containing composition (100%). Details of the carbonate compound and the catalyst will be described later.

[0113] In the method for producing a polycarbonate diol of the present invention, since the dihydroxy compound-containing composition contains the compound (2-1), a polycarbonate diol having a molecular weight close to the theoretical molecular weight can be obtained in high yield. Furthermore, the obtained polycarbonate diol can be used to obtain a polyurethane having excellent mechanical properties and chemical resistance and reduced variations in the mechanical properties.

[0114] In the present invention, the theoretical molecular weight of polycarbonate diol refers to the molecular weight calculated from the charging ratio of the dihydroxy compound and the carbonate compound when the dihydroxy compound and the carbonate compound, which are raw materials, react 100% and all of the dihydroxy compound becomes a constituent unit of polycarbonate diol, and is calculated using the molecular weight and molar amount of the dihydroxy compound, the molar amount of the carbonate compound, and the following formula.

[0115]

[0116] In the method for producing the polycarbonate diol of the present invention, the compound (1-1) and the compound (2-1) are treated as having the same meaning as the compound (1-1) and the compound (2-1) described in the description of the polycarbonate diol of the present invention, respectively.

[0117] As one embodiment of the method for producing a polycarbonate diol of the present invention, a method using diphenyl carbonate as the carbonate compound will be described below. The production of a polycarbonate diol can be carried out in two stages. In the first stage reaction, compound (1-1), compound (2-1), and diphenyl carbonate are mixed in a molar ratio of compound (1-1):{carbonate compound + compound (2-1)}=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 the phenol and unreacted compounds (1-1) and (2-1) from the reaction system, thereby obtaining a polycarbonate diol having a predetermined molecular weight.

[0118] (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 carbonate compounds from these can be used as a raw material. Among these, from the viewpoints of reactivity with the compound (1-1), 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 those skilled in the art can use, for example, the conditions described in WO 2015 / 199070 by optimizing them appropriately according to known techniques.

[0119] (Catalyst) In the method for producing a polycarbonate diol of the present invention, when compound (1-1) and compound (2-1) are polycondensed with a carbonate compound via a transesterification reaction to obtain a polycarbonate diol, a known transesterification catalyst (hereinafter sometimes 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, the polycarbonate diol may become discolored, or the reaction may be inhibited or excessively promoted 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, the 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.

[0120] 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 bicarbonate, 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, prevent an excessive increase in the molecular weight of the polycarbonate diol, and reduce the amount of catalyst residue in the polycarbonate diol obtained using a relatively small amount of catalyst, even when producing a polycarbonate diol using the compound (1-1) and the compound (2-1). The amount of the titanium atom-containing catalyst used can be 50 mass ppm or less, 35 mass ppm or less, or 25 mass ppm or less, calculated as titanium atoms, relative to the total mass of the dihydroxy compound-containing composition. However, if the amount of catalyst is too small, a sufficient catalytic effect cannot be obtained, so the amount of the titanium atom-containing catalyst used is preferably 1 mass ppm or more, particularly 2 mass ppm or more, and particularly 3 mass ppm or more, calculated as titanium atoms, relative to the total mass of the dihydroxy compound-containing composition.

[0121] (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, 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.

[0122] (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.

[0123] (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.

[0124] <Polyurethane> The polyurethane of the present invention is a polyurethane obtained using the polycarbonate diol of the present invention and an isocyanate compound as raw materials. It should be noted that compounds other than the polycarbonate diol and the isocyanate compound can be used as raw materials for the polyurethane of the present invention, as long as the effects of the present invention are not impaired. The polycarbonate diol of the present invention contains the structural unit (2) described above, thereby improving its crystallinity. As a result, the crystallinity of polyurethanes obtained using the polycarbonate diol of the present invention as a raw material is improved, and further, the interaction between polyurethane chains is strengthened, which is expected to result in excellent mechanical properties and chemical resistance of the polyurethane and suppression of variation in the mechanical properties.

[0125] 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.

[0126] For example, the polyurethane of the present invention can be produced by reacting the polycarbonate diol of the present invention with a polyol other than the polycarbonate diol of the present invention, which is used as needed, an isocyanate compound described below, and a chain extender described below, which is also used as needed, at a temperature ranging from room temperature to 200°C. 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 of the present invention with an excess 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.

[0127] (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.

[0128] (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.

[0129] (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.

[0130] (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.

[0131] (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.

[0132] (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.

[0133] (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 120,000 to 200,000.

[0134] <Uses of Polyurethane> The polyurethane of the present invention has good mechanical properties and chemical resistance, 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.

[0135] [Effects] The polycarbonate diol of the present invention contains a predetermined amount of the compound (2-1), i.e., dicarboxylic acid or dicarboxylic acid derivative, in the dihydroxy compound-containing composition used in producing the polycarbonate diol. This improves catalytic activity and allows for the provision of a polycarbonate diol with a predetermined molecular weight in high yield. While the reason why a predetermined amount of dicarboxylic acid or dicarboxylic acid derivative improves catalytic activity is unclear, it is presumed as follows. According to the inventors' studies, when polycarbonate diol is polymerized, the molecular weight of the polycarbonate diol increases if unreacted diol is distilled off. It is presumed that when polycarbonate diol is polymerized using a dihydroxy compound-containing composition containing a dicarboxylic acid or dicarboxylic acid derivative, the dicarboxylic acid or dicarboxylic acid derivative coordinates with the catalyst, improving catalytic activity. It is presumed that improved catalytic activity promotes the reaction between the dihydroxy compound and the carbonate compound, reducing the amount of unreacted dihydroxy compound, thereby reducing the amount of dihydroxy compound distilled off and suppressing the increase in the molecular weight of the polycarbonate diol. Furthermore, if there is an excess of dicarboxylic acid or dicarboxylic acid derivative, the remaining dicarboxylic acid or dicarboxylic acid derivative reacts with the polycarbonate diol during the reaction, causing an elongation reaction of the molecular chain, which is presumably the result of an increase in the molecular weight of the polycarbonate diol.

[0136] Furthermore, the polycarbonate diol composition of the present invention contains the structural unit (2), and thus can provide a polyurethane that is excellent in mechanical properties and chemical resistance and has reduced variations in the mechanical properties. The reason for this is not clear, but is presumed to be as follows.

[0137] When polyurethane is produced using the polycarbonate diol of the present invention as a raw material, the structural unit (2) contained in the polycarbonate diol has an ester bond, and hydrogen bonding interactions between polyurethane molecules are improved via ester bonds or ester bonds and amide bonds. It is presumed that the hydrogen bonding interactions cause the bonding sites to act as crosslinking points or crystalline hard segment structures, improving the mechanical properties of the polyurethane.

[0138] Furthermore, polyurethanes obtained using polycarbonate diols containing the structural unit (2) have an appropriate viscosity due to the improved interaction between polyurethane molecules caused by hydrogen bonds. As a result, the uniformity of the polyurethane composition can be efficiently improved by stirring. Furthermore, the appropriate improvement in viscosity improves the coating stability and molding stability of polyurethanes or polyurethane-containing compositions, thereby improving the dimensional stability of the resulting film-like materials, fibrous materials, and other molded articles. This is thought to suppress variation in the mechanical properties of the resulting polyurethane products.

[0139] 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.

[0140] [Raw Materials Used] The abbreviations for the raw materials used in the Examples and Comparative Examples are as follows. <Compound (1-1)> 16HD: 1,6-hexanediol (manufactured by BASF Corporation) 14BD: 1,4-butanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) <Carbonate Compounds> DPC: diphenyl carbonate (manufactured by Mitsubishi Chemical Corporation) DEC: diethyl carbonate (manufactured by Tokyo Chemical Industry Co., Ltd.) <Catalyst> TBT: tetrabutyl orthotitanate (manufactured by Tokyo Chemical Industry Co., Ltd.) <Compound (2-1)> dibutyl succinate (manufactured by Tokyo Chemical Industry Co., Ltd.) succinic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) disodium succinate (manufactured by Tokyo Chemical Industry Co., Ltd.) <Raw Materials for Urethane Synthesis> MDI: diphenylmethane diisocyanate (manufactured by Tosoh Corporation) U-830: dioctyltin monodecanoate (trade name: Neostan U-830, manufactured by Nitto Chemical Industry Co., Ltd.) DMF: N,N-dimethylformamide dehydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0141] [Evaluation Method] In the following, the evaluation method for each physical property value is as follows.

[0142] <14BD / 16HD Ratio in Polycarbonate Diol (Content of Structural Unit (1b))> The polycarbonate diols obtained in the examples and comparative examples were each dissolved in CDCl ３ The sample was dissolved in deuterated chloroform and subjected to nuclear magnetic resonance spectroscopy using a nuclear magnetic resonance spectrometer (400 MHz, manufactured by JEOL Ltd., model name: ECZ400S) at a measurement temperature of 30°C and an accumulation number of 64 cycles. １ H-NMR measurement was carried out. １ From the H-NMR measurement results, the peaks observed at the following signal positions were identified, and integral values ​​A to E of each peak were obtained. Integration value of 4H proton of methylene group of structure derived from succinic acids in polycarbonate diol present at δ 2.60 to 2.55 ppm = A Integration value of 4H proton peak of methylene group next to carbonate bond in polycarbonate diol present at δ 4.35 to 3.85 ppm = B Integration value of 2H proton peak of methylene group next to hydroxyl group terminal in polycarbonate diol present at δ 3.70 to 3.50 ppm = C Integration value of 4H proton peak of β methylene group of structure derived from 1,6-hexanediol and 1,4-butanediol in polycarbonate diol present at δ 1.90 to 1.50 ppm = D Integration value of 4H proton peak of γ methylene group of structure derived from 1,6-hexanediol in polycarbonate diol present at δ 1.45 to 1.25 ppm = E

[0143] The 14BD / 16HD ratio was calculated using the following formulas based on the number of protons in the structural unit derived from 1,4-butanediol (hereinafter abbreviated as "14BD") and the structural unit derived from 1,6-hexanediol (hereinafter abbreviated as "16HD"): (16HD ratio) = E / D (14BD ratio) = 1 - E / D (14BD / 16HD ratio) = (14BD ratio) x 100 / (16HD ratio) x 100

[0144] <Molecular weight M(PCD) of polycarbonate diol> The molecular weight M(PCD) of polycarbonate diol obtained by measuring the "14BD / 16HD ratio in polycarbonate diol" described above. １From the H-NMR measurement results, the integral value of the peak derived from the structural unit in the polycarbonate diol derived from succinic acids (hereinafter referred to as "structural unit derived from succinic acids") is defined as "SA ｏ ". The "structural unit derived from succinic acids" can be treated as synonymous with "structural unit (2)" in the present invention. In addition, the integral value of the peak derived from the structural unit at the terminal of the polycarbonate diol derived from 16HD was defined as "16HD ｍ ", and the integral value of the peak derived from the structural unit of the polycarbonate diol terminal derived from 14BD is "14BD ｍ ". The integral value of the peak derived from the structural unit derived from 16HD in the polycarbonate diol other than the polycarbonate diol terminal was defined as "16HD ｏ ", and the integral value of the peak derived from the structural unit derived from 14BD is "14BD ｏ Taking into account the number of protons in each group, the integral value per proton was calculated using the following formula: (SA ｏ )=A÷4 (16HD ｍ )=E÷D×C÷2 (16HD ｏ )=(E÷D×B-16HD ｍ ×2)÷4 (14BD ｍ )=(1-E÷D)×C÷2 (14BD ｏ )={(1-E÷D)×B-14BD ｍ × 2÷ 4

[0145] Next, the molecular weight M(PCD) of the polycarbonate diol was calculated using the following formula.

[0146]

[0147] In the above formula, M(SA ｏ ) is the molecular weight of the structural unit derived from succinic acid in the polycarbonate diol (=84), M(16HD ｏ ) is the molecular weight of the carbonate structural unit derived from 16HD in the polycarbonate diol other than the polycarbonate diol terminal (=144), M(14BD ｏ) is the molecular weight of the carbonate structural unit derived from 14BD in the polycarbonate diol other than the polycarbonate diol terminal (=116), M(16HD ｍ ) is the molecular weight of the carbonate structural unit derived from 16HD at the end of the polycarbonate diol (=262), M(14BD ｍ ) refers to the molecular weight (=206) of the carbonate structural unit derived from 14BD at the end of the polycarbonate diol.

[0148] <Content of Structural Units Derived from Succinic Acids in Polycarbonate Diol (Content of Structural Unit (2))> The content of the structural unit (2) obtained by measuring the "14BD / 16HD ratio in the polycarbonate diol" described above. １ The content (unit: mol%) of the structural unit derived from succinic acids in the polycarbonate diol was calculated using the integral value of the peak derived from each structural unit obtained from the H-NMR measurement results and the following formula.

[0149]

[0150] <Hydroxyl Value of Polycarbonate Diol> The hydroxyl value (unit: mgKOH / g) of the polycarbonate diol obtained in the examples and comparative examples was measured by a method using an acetylating reagent in accordance with JIS K1557-1.

[0151] <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.

[0152] 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.

[0153] <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.

[0154] 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.

[0155] (Tensile Test) A tensile test was carried out on the above tensile test specimens in accordance with JIS K6301 (2010) using a bench-top precision universal testing machine (Shimadzu Corporation, product name: Autograph AGS-X) with 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 four tensile test specimens, and the 100% modulus and 300% modulus, as well as the average value and standard deviation of the stress (breaking strength) at the time the specimen broke, were measured. The following formula was used to calculate the coefficient of variation of the 100% modulus, 300% modulus, and breaking strength. Coefficient of variation (%) = (standard deviation / average value) x 100

[0156] The coefficient of variation is an index for evaluating the relative variation of the data. The smaller the coefficient of variation, the smaller the variation in the numerical values ​​of the tensile test properties, and therefore the more homogeneous the polyurethane that can be obtained.

[0157] <Chemical Resistance of Polyurethane> As an index of the chemical resistance of polyurethane, the mass change rate when polyurethane was immersed in a test solution was measured using the following method.

[0158] 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 then dried at 80°C for 1 hour, then at 100°C for 0.5 hours, and then at 100°C in a vacuum for 1.0 hour to remove the solvent (DMF), resulting in 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, a square polyurethane film (3 cm long, 3 cm wide, 90±20 μm thick) was cut out and used as a sample piece for chemical resistance testing.

[0159] (Oleic Acid Resistance Test) The weight of the above-mentioned chemical resistance test specimen was measured using a precision balance, and then the specimen was placed in a glass Petri dish with an inner diameter of 10 cm containing 50 mL of oleic acid as a test solvent, and immersed at 80°C for 16 hours. After the test, the specimen was removed and lightly wiped on both sides with a paper wiper, and then the mass was measured using a precision balance. The mass change rate (increase rate) was calculated from the change in mass of the specimen before and after the test. A mass change rate closer to 0% indicates better oleic acid resistance.

[0160] (Ethanol Resistance Test) The weight of the above-mentioned chemical resistance test specimen was measured using a precision balance, and then the specimen was placed in a glass petri dish with an inner diameter of 10 cm containing 50 mL of ethanol as a test solvent, and immersed for 1 hour at room temperature of about 23°C. After the test, the specimen was removed and lightly wiped on both sides with a paper wiper, and then the mass was measured using a precision balance. The mass change rate (increase rate) was calculated from the change in mass of the specimen before and after the test. A mass change rate closer to 0% indicates better ethanol resistance.

[0161] <Hydrolysis Resistance of Polyurethane> As an index of the hydrolysis resistance of polyurethane, the breaking strength retention rate when the polyurethane was stored in a constant temperature and humidity environment was measured using the following method.

[0162] 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 hydrolysis resistance tests.

[0163] The test specimens for hydrolysis resistance were stored in a thermo-hygrostat at 70°C and 95% RH for 2 weeks. After the test, the test specimens were removed from the thermo-hygrostat and left to stand in an environment of 23°C and 55% RH for 48 hours or more.

[0164] After the hydrolysis resistance test, the test pieces were subjected to a tensile test in accordance with JIS K6301 (2010) using a bench-top precision universal testing machine (Shimadzu Corporation, product name: Autograph AGS-X) with 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 performed using three test pieces, and the average stress (breaking strength) at the time the test pieces broke was measured. The following formula was used to calculate the retention of breaking strength:

[0165] Breaking strength retention rate (%) = (average breaking strength after hydrolysis resistance test / average breaking strength before hydrolysis resistance test) x 100

[0166] The closer to 100% the retention rate of breaking strength before and after the hydrolysis resistance test, the better the hydrolysis resistance of the polyurethane.

[0167] <Evaluation of Polycarbonate Diol (1)> The following experiment was carried out to examine the effect of the compound (2-1) in the dihydroxy compound-containing composition on the molecular weight and yield of the obtained polycarbonate diol.

[0168] Comparative Example 1: A 1-L separable glass flask equipped with a stirrer, a distillate trap, and a pressure regulator was charged with 16HD and 14BD as dihydroxy compounds, DPC as a carbonate compound, and TBT as a transesterification catalyst in the amounts shown in Table 1. The flask was then purged with a nitrogen atmosphere, and the contents were heated to 160°C while stirring, dissolving the contents. The pressure inside the flask at this time was 101 kPa. The pressure inside the flask was then gradually reduced from 101 kPa to 24 kPa over 2 minutes, and the reaction was allowed to proceed for 90 minutes while removing the produced phenol from the reaction system. The pressure inside the flask was then gradually reduced to 9.3 kPa over 90 minutes, and then further reduced to 0.7 kPa over 60 minutes. The reaction was continued, and the temperature of the contents was then increased to 170°C. The reaction was allowed to proceed for another 90 minutes while removing phenol and unreacted dihydroxy compounds from the reaction system. Thereafter, the temperature of the contents was allowed to cool to room temperature to obtain 144 g of polycarbonate diol. The obtained polycarbonate diol (PCD) was subjected to the above-mentioned evaluations, and the evaluation results are shown in Table 1.

[0169] [Example 1] A reaction was carried out under the same conditions as in Comparative Example 1, except that 7 mg of dibutyl succinate was added to the raw materials. After the reaction, the temperature of the content was allowed to cool to room temperature, and 148 g of polycarbonate diol was obtained. The obtained polycarbonate diol (PCD) was evaluated as described above, and the evaluation results are shown in Table 1.

[0170] [Example 2] A reaction was carried out under the same conditions as in Comparative Example 1, except that 13 mg of dibutyl succinate was added to the raw materials. After the reaction, the temperature of the content was allowed to cool to room temperature, and 149 g of polycarbonate diol was obtained. The obtained polycarbonate diol (PCD) was evaluated as described above, and the evaluation results are shown in Table 1.

[0171] [Example 3] A reaction was carried out under the same conditions as in Comparative Example 1, except that 66 mg of dibutyl succinate was added to the raw materials. After the reaction, the temperature of the content was allowed to cool to room temperature, and 149 g of polycarbonate diol was obtained. The obtained polycarbonate diol (PCD) was evaluated as described above, and the evaluation results are shown in Table 1.

[0172] [Example 4] A reaction was carried out under the same conditions as in Comparative Example 1, except that 1,317 mg of dibutyl succinate was added to the raw materials. After the reaction, the temperature of the content was allowed to cool to room temperature, and 148 g of polycarbonate diol was obtained. The obtained polycarbonate diol (PCD) was evaluated as described above, and the evaluation results are shown in Table 1.

[0173] [Example 5] A reaction was carried out under the same conditions as in Comparative Example 1, except that 33 mg of succinic acid was added to the raw material. After the reaction, the temperature of the content was allowed to cool to room temperature, and 149 g of polycarbonate diol was obtained. The obtained polycarbonate diol (PCD) was evaluated as described above, and the evaluation results are shown in Table 1.

[0174] [Example 6] A reaction was carried out under the same conditions as in Comparative Example 1, except that 71 mg of disodium succinate was added to the raw materials. After the reaction, the temperature of the content was allowed to cool to room temperature, and 147 g of polycarbonate diol was obtained. The obtained polycarbonate diol (PCD) was evaluated as described above, and the evaluation results are shown in Table 1.

[0175] [Example 7] A reaction was carried out under the same conditions as in Comparative Example 1, except that 3970 mg of dibutyl succinate was added to the raw materials. After the reaction, the temperature of the content was allowed to cool to room temperature, and 151 g of polycarbonate diol was obtained. The obtained polycarbonate diol (PCD) was evaluated as described above, and the evaluation results are shown in Table 1.

[0176] [Comparative Example 2] A 1 L glass separable flask equipped with a stirrer, a distillate trap, a packed column, and a pressure regulator was charged with 16HD and 14BD as dihydroxy compounds, DEC as a carbonate compound, and TBT as a transesterification catalyst in the amounts shown in Table 1. The flask was then purged with a nitrogen atmosphere, and the contents were heated to 130 ° C. while stirring the contents, and the contents were dissolved by heating. The pressure in the flask at this time was 101 kPa. The pressure in the flask was then reduced from 101 kPa to 93 kPa, and the temperature of the flask contents was adjusted to 130-145 ° C. so that the top temperature of the distillation pipe was 75 ° C. The reaction was carried out for 240 minutes while removing the produced ethanol from the reaction system. Next, the temperature of the flask contents was increased to 150 ° C., and the pressure in the flask was gradually reduced from 93 kPa to 1.3 kPa over 210 minutes. Thereafter, the packed column of the distillation piping was removed, and the temperature of the content was raised to 165°C, and the pressure inside the flask was reduced to 0.7 kPa. Then, the temperature of the content was gradually raised from 165°C to 175°C, while ethanol and unreacted diethyl carbonate and dihydroxy compound were removed from the reaction system, and the reaction was carried out at 0.7 kPa for 360 minutes. Thereafter, the temperature of the content was allowed to cool to room temperature, and 134 g of polycarbonate diol was obtained. The obtained polycarbonate diol was evaluated as described above, and the evaluation results are shown in Table 1.

[0177] [Example 8] A reaction was carried out under the same conditions as in Comparative Example 2, except that 67 mg of dibutyl succinate was added to the raw materials. After the reaction, the temperature of the content was allowed to cool to room temperature, and 140 g of polycarbonate diol was obtained. The obtained polycarbonate diol was evaluated as described above, and the evaluation results are shown in Table 1.

[0178] Furthermore, from the results of Comparative Example 1 and Examples 1 to 7 above, the relationship between the content ratio of compound (2-1) in the dihydroxy compound-containing composition and the molecular weight M(PCD) of the polycarbonate diol is graphed in FIG. 1, the relationship between the content ratio of compound (2-1) in the dihydroxy compound-containing composition and the yield of the polycarbonate diol is graphed in FIG. 2, and the relationship between the content ratio of structural unit (2) in the polycarbonate diol and the molecular weight M(PCD) of the polycarbonate diol is graphed in FIG. 3.

[0179]

[0180] The following can be seen from Table 1. In Examples 1 to 7, polycarbonate diols having molecular weights close to the theoretical molecular weight were obtained in high yields. On the other hand, in Comparative Example 1, the dihydroxy compound-containing composition did not contain compound (2-1), so the molecular weight of the obtained polycarbonate diol was higher than the theoretical molecular weight and the yield of polycarbonate diol was lower compared to the Examples. Furthermore, from Example 8 and Comparative Example 2, even for polycarbonate diols synthesized not only with DPC but also with DEC, the dihydroxy compound-containing composition contained compound (2-1), so the molecular weight of the obtained polycarbonate diol in Example 8 was close to the theoretical molecular weight and the yield of polycarbonate diol was higher than that of Comparative Example 2. Furthermore, from a comparison of the Examples and Comparative Examples in FIG. 1, it was confirmed that the inclusion of compound (2-1) in the dihydroxy compound-containing composition brought the molecular weight of the polycarbonate diol (M(PCD)) closer to the theoretical molecular weight. In particular, when the content of compound (2-1) in the dihydroxy compound-containing composition is in the range of 0.005% by mass or more and 1.500% by mass or less, the molecular weight of the polycarbonate diol (M(PCD)) is close to the theoretical molecular weight. From FIG. 2 , comparing the Examples and Comparative Examples, it was confirmed that the yield of polycarbonate diol is improved by including compound (2-1) in the dihydroxy compound-containing composition. From FIG. 3 , it was confirmed that the molecular weight of the polycarbonate diol (M(PCD)) is close to the theoretical molecular weight by including the structural unit (2) in the obtained polycarbonate diol. In particular, it was confirmed that the molecular weight of the polycarbonate diol (M(PCD)) is close to the theoretical molecular weight when the content of structural unit (2) in the polycarbonate diol is in the range of 0.001 mol % or more and 0.900 mol % or less.

[0181] <Evaluation of Polycarbonate Diol (2)> The following experiment was carried out to investigate the effect of compound (2-1) in the dihydroxy compound-containing composition on the molecular weight of the polycarbonate diol obtained after thin-film distillation. By investigating the molecular weight of the polycarbonate diol after thin-film distillation, it is possible to understand the effect that the removal of low-molecular-weight components such as monomers by thin-film distillation has on the PCD molecular weight. Since the molecular weight of polycarbonate diol containing a large amount of low-molecular-weight components approaches the theoretical molecular weight in appearance, the molecular weight of PCD was confirmed under conditions in which the low-molecular-weight components were removed.

[0182] Comparative Example 3-1: 16HD and 14BD as dihydroxy compounds, DPC as a carbonate compound, and TBT as a transesterification catalyst were added to a 1 L glass separable flask equipped with a stirrer, a distillate trap, and a pressure regulator in the amounts shown in Table 2. The atmosphere in the flask was replaced with a nitrogen atmosphere, and the contents in the flask were heated to 160°C while stirring, thereby dissolving the contents. The pressure in the flask at this time was 101 kPa. The pressure in the flask was then gradually reduced from 101 kPa to 24 kPa over 2 minutes, and the reaction was carried out for 90 minutes while the produced phenol was removed from the reaction system. Next, the pressure in the flask was gradually reduced to 9.3 kPa over 90 minutes, and then further reduced to 0.7 kPa over 60 minutes. After continuing the reaction, the temperature of the contents was raised to 170°C, and the reaction was continued for another 90 minutes while phenol and unreacted dihydroxy compound were removed from the reaction system. The temperature of the contents was then allowed to cool to 120°C, and the pressure was increased to atmospheric pressure to obtain a polycarbonate diol. To the obtained polycarbonate diol, a 0.85% by mass aqueous phosphoric acid solution was added in the amount shown in Table 2 to deactivate the TBT catalyst contained therein, and the mixture was stirred at 120°C for 1 hour. The solution was then pumped to a thin-film distillation apparatus at a flow rate of 20 g / min, and thin-film distillation (temperature: 180-190°C, pressure: 40-67 Pa) was carried out. The thin-film distillation apparatus had a diameter of 50 mm, a height of 200 mm, and an area of ​​0.0314 m. ２An MS-300 special model molecular distillation apparatus equipped with an internal condenser and a jacket, manufactured by Shibata Scientific Co., Ltd., was used. The obtained polycarbonate diol was designated "PCD1". The evaluation results of PCD1 are shown in Table 2.

[0183] [Example 9-1] A reaction was carried out under the same conditions as in Comparative Example 3-1, except that 23 mg of dibutyl succinate was added to the raw materials. The obtained polycarbonate diol was designated "PCD2". The evaluation results of PCD2 are shown in Table 2.

[0184] [Example 10-1] A reaction was carried out under the same conditions as in Comparative Example 3-1, except that 115 mg of dibutyl succinate was added to the raw materials. The obtained polycarbonate diol was designated "PCD3". The evaluation results of PCD3 are shown in Table 2.

[0185] [Example 11-1] A reaction was carried out under the same conditions as in Comparative Example 3-1, except that 2298 mg of dibutyl succinate was added to the raw materials. The obtained polycarbonate diol was designated "PCD4". The evaluation results of PCD4 are shown in Table 2.

[0186] [Example 12-1] A reaction was carried out under the same conditions as in Comparative Example 3-1, except that 6915 mg of dibutyl succinate was added to the raw materials. The obtained polycarbonate diol was designated "PCD5". The evaluation results of PCD5 are shown in Table 2.

[0187]

[0188] The following can be seen from Table 2. In Examples 9-1 to 12-1, polycarbonate diols having molecular weights close to the theoretical molecular weight were obtained in high yields. On the other hand, in Comparative Example 3-1, the dihydroxy compound-containing composition did not contain compound (2-1), so the molecular weight of the obtained polycarbonate diol was larger than the theoretical molecular weight compared to the Examples. It was confirmed that even in the polycarbonate diol after low molecular weight components were removed by thin-film distillation, the molecular weight of the obtained polycarbonate diol was close to the theoretical molecular weight because the dihydroxy compound-containing composition contained compound (2-1).

[0189] <Evaluation of Polyurethane> The following experiment was carried out to examine the effect of the structural unit (2) in the polycarbonate diol on the performance of the obtained polyurethane.

[0190] [Comparative Example 3-2] Using PCD1 obtained in Comparative Example 3-1, polyurethane was synthesized and evaluated according to the following procedure. A separable flask equipped with a thermocouple and a condenser was charged with 77.8 g of PCD1 preheated to 80°C, 4.72 g of 14BD as a chain extender, 0.02 g of U-830 as a catalyst, and 239 g of DMF as a reaction solvent, and the mixture was immersed in an oil bath set at 55°C and stirred at a stirring speed of 60 rpm until homogeneous. The water content of 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 equivalent to an NCO / OH molar ratio of 0.900 (including water correction) was added in a solid state to the reaction solution as an isocyanate compound using a funnel, and the mixture was stirred and mixed at a stirring speed of 60 rpm until homogeneous. In this specification, the "NCO / OH molar ratio" refers to the ratio (molar ratio) of the total amount of substance (number of moles) of MDI to the value obtained by subtracting the total amount of substance (number of moles) of water contained from the total amount of substance (number of moles) of polycarbonate diol and 14BD at the time of adding MDI. Immediately after adding MDI, an exothermic peak accompanied by a rise in the temperature of the reaction solution by +10 to 15°C was observed, and 5 minutes after the exothermic peak had subsided, the temperature of the oil bath was set to 70°C and the temperature was increased.

[0191] 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 147,163 was finally obtained. The evaluation results for the resulting polyurethane are shown in Table 3.

[0192] Examples 9-2 to 12-2 Polyurethane solutions were obtained by polymerization under the same conditions and in the same manner as in Comparative Example 3-2, except that PCD2, PCD3, PCD4, and PCD5 obtained in Examples 9-1 to 12-1, respectively, were used instead of PCD1 in Comparative Example 3-2, and the amounts of each raw material charged were changed to the amounts shown in Table 3. The evaluation results of the obtained polyurethanes are shown in Table 3.

[0193]

[0194] Regarding the evaluation results of the mechanical property tests in Table 3, the results for the breaking strength, 100% modulus, and 300% modulus are shown in Figures 4 to 6, respectively. Furthermore, regarding the evaluation results of the coefficient of variation in the mechanical property tests in Table 3, the coefficients of variation for the breaking strength, 100% modulus, and 300% modulus are shown in Figures 7 to 9, respectively. Furthermore, regarding the evaluation results of the chemical resistance tests in Table 3, the results of the oleic acid resistance test are shown in Figure 10, and the test results for ethanol resistance are shown in Figure 11.

[0195] The following can be seen from Table 3 and Figures 4 to 11. The polyurethanes obtained in Examples 9-2 to 12-2 were superior in terms of breaking strength, 100% modulus, and 300% modulus compared to the polyurethane obtained in Comparative Example 3-2. Furthermore, the mechanical properties were particularly excellent when the content of structural unit (2) in the PCD was around 0.001 to 0.35 mol%. Furthermore, the polyurethanes obtained in Examples 9-2 to 12-2 had smaller coefficients of variation (variation) in all mechanical properties compared to the polyurethane obtained in Comparative Example 3-2. Furthermore, the coefficients of variation (variation) were particularly small when the content of structural unit (2) in the PCD was around 0.001 to 0.35 mol%. Furthermore, the polyurethanes obtained in Examples 9-2 to 12-2 had superior chemical resistance compared to the polyurethane obtained in Comparative Example 3-2. Furthermore, when the content of the structural unit (2) in the PCD was around 0.001 to 0.02 mol %, the chemical resistance was particularly excellent.

[0196] On the other hand, the polyurethane obtained in Comparative Example 3-2 was inferior in mechanical properties and chemical resistance and had a large coefficient of variation (variation) of mechanical properties because the polycarbonate diol used as a raw material did not contain the structural unit derived from succinic acid in the polycarbonate diol structure.

[0197] From the above, it can be seen that the polycarbonate diol of the present invention can provide polyurethane that is excellent in mechanical properties and chemical resistance and has reduced variations in the mechanical properties.

[0198] Furthermore, the results of the breaking strength retention rate for the evaluation results of the hydrolysis resistance test in Table 3 are shown in Figure 12. From Table 3 and Figure 12, it can be seen that the polyurethanes obtained in Examples 9-2 to 11-2 had superior hydrolysis resistance compared to the polyurethane obtained in Comparative Example 3-2. That is, it can be seen that the polycarbonate diol of the present invention not only makes it possible to obtain polyurethanes that are excellent in mechanical properties and chemical resistance and have reduced variation in the mechanical properties, but also makes it possible to make the hydrolysis resistance of the obtained polyurethanes even better by setting the content ratio of structural units derived from succinic acid within a specific range.

Claims

1. A polycarbonate diol containing a structural unit (1) represented by the following general formula (I) and a structural unit (2) represented by the following general formula (II), wherein the content of the structural unit (2) in the polycarbonate diol is 4.3 mol % or less relative to 100 mol % of all structural units in the polycarbonate diol. (In the above general formula (I), n is an integer of 4 to 6.) (In the above general formula (II), m is an integer of 2 to 4.) 2. The polycarbonate diol according to claim 1, wherein the content of the structural unit (2) in the polycarbonate diol is 3.0 mol % or less relative to 100 mol % of all structural units in the polycarbonate diol.

3. The polycarbonate diol according to claim 1, wherein the structural unit (1) represented by general formula (I) includes a structural unit derived from a biomass-derived dihydroxy compound.

4. The polycarbonate diol according to claim 1, wherein the structural unit (1) represented by general formula (I) is derived from a biomass-derived dihydroxy compound alone, or a mixture containing a biomass-derived dihydroxy compound and a fossil fuel-derived dihydroxy compound.

5. The polycarbonate diol according to claim 3, wherein the biomass-derived dihydroxy compound is a compound derived from non-edible biomass and / or non-fossil fuel.

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

7. A method for producing a polycarbonate diol, comprising transesterifying a dihydroxy compound-containing composition containing a compound (1-1) represented by the following general formula (I-1) and a compound (2-1) represented by the following general formula (II-1) with a carbonate compound in the presence of a catalyst to obtain a polycarbonate diol, wherein the content of compound (2-1) in the dihydroxy compound-containing composition is 5.3 mass% or less, relative to 100% of the total mass of the dihydroxy compound-containing composition. (In the above general formula (I-1), n ​​is an integer of 4 to 6.) (In the above general formula (II-1), m is an integer of 2 to 4. R １ represents a hydrogen atom, a heteroatom, or an alkyl group having 2 to 20 carbon atoms which may have a heteroatom or a substituent. １ may be the same or different.) 8. In the compound (2-1), R １ and at least one of the above is an alkyl group having 2 to 20 carbon atoms which may have a heteroatom or a substituent.

9. The method for producing a polycarbonate diol according to claim 7, wherein the catalyst contains titanium atoms and the amount of the catalyst is 50 mass ppm or less in terms of titanium atoms relative to the total mass of the dihydroxy compound-containing composition.

10. A polyurethane made from the polycarbonate diol according to any one of claims 1 to 6 and an isocyanate compound.

11. The polyurethane according to claim 10, 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.

12. A dihydroxy compound-containing composition comprising a compound (1-1) represented by the following general formula (I-1) and a compound (2-1) represented by the following general formula (II-1), wherein the content of compound (2-1) in the dihydroxy compound-containing composition is 5.3 mass% or less, relative to the total mass of the dihydroxy compound-containing composition (100%). (In the above general formula (I-1), n ​​is an integer of 4 to 6.) (In the above general formula (II-1), m is an integer of 2 to 4. R １ represents a hydrogen atom, a heteroatom, or an alkyl group having 2 to 20 carbon atoms which may have a heteroatom or a substituent. １ may be the same or different.) 13. The dihydroxy compound-containing composition according to claim 12, wherein the content of the compound (1-1) in the dihydroxy compound-containing composition is 40.0 mass% or more relative to 100% of the total mass of the dihydroxy compound-containing composition.

14. In the compound (2-1), R １ 13. The dihydroxy compound-containing composition according to claim 12, wherein at least one of the above is an alkyl group having 2 to 20 carbon atoms, which may have a heteroatom or a substituent.

15. The dihydroxy compound-containing composition according to claim 12, wherein the compound (1-1) comprises 1,4-butanediol.

16. In the compound (2-1), R １ 15. The dihydroxy compound-containing composition according to claim 14, wherein at least one of the above is an alkyl group having 4 carbon atoms, which may have a heteroatom or a substituent.

17. The dihydroxy compound-containing composition according to claim 12, wherein the compound (I-1) comprises a biomass-derived diol.

18. The dihydroxy compound-containing composition according to claim 12, which is used in a process for producing a polycarbonate diol.

19. A polycarbonate diol made from the dihydroxy compound-containing composition according to any one of claims 12 to 18 and a carbonate compound.

20. A polyurethane made from the polycarbonate diol of claim 19 and an isocyanate compound.

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