Diol-containing composition, polycarbonate diol, and polyurethane

Abstract

To provide a diol-containing composition that is used in a process of producing a polycarbonate diol and that is capable of producing a polyurethane with excellent mechanical properties and chemical resistance, in which variations in the mechanical properties are suppressed, while maintaining the quality of the polycarbonate diol produced, such as its color tone.SOLUTION: A diol-containing composition used in a process of producing a polycarbonate diol comprises an aldehyde and a diol (1) represented by the following general formula (1). HO-(CH2)n-OH (1) (In general formula (1), n is an integer from 3 to 6.)SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a diol-containing composition. Furthermore, the present invention relates to a polycarbonate diol produced from the diol-containing composition, and a polyurethane obtained by using the polycarbonate diol. [Background technology]

[0002] Straight-chain aliphatic diols having 3 to 6 carbon atoms, such as 1,6-hexanediol and 1,4-butanediol, are widely used as raw materials for oligomers, such as polyether polycarbonate diols, polyester polycarbonate diols, and polycarbonate diols. For example, polycarbonate-type polyurethanes, which use polycarbonate diol as the raw material for the soft segment, are considered to have the best durability in terms of heat resistance and hydrolysis resistance, and are widely used in durable films, artificial leather for automobiles, (water-based) paints, and adhesives.

[0003] In polycarbonate diols currently widely available on the market, linear aliphatic diols having 3 to 6 carbon atoms, such as 1,6-hexanediol and 1,4-butanediol, are mainly used as dihydroxy compounds as raw materials. Furthermore, in order to improve the flexibility, crystallinity, strength, etc. of polyurethane, aliphatic polycarbonate diols using linear aliphatic diols having 3 to 6 carbon atoms, such as 1,6-hexanediol, in combination with each other or the linear aliphatic diol in combination with another dihydroxy compound have been proposed.

[0004] For example, Patent Document 1 discloses a technique for improving the flexibility and elastic recovery of the resulting polyurethane by combining 1,6-hexanediol and 1,5-pentanediol as dihydroxy compounds that are raw materials for polycarbonate diol. Patent Document 2 discloses a technique for improving the oil resistance, heat resistance, and cold resistance of the resulting polyurethane by combining 1,6-hexanediol and 1,4-butanediol as dihydroxy compounds, which are raw materials for polycarbonate diol. Furthermore, Patent Document 3 discloses a technique for improving the strength and hardness of the resulting polyurethane by combining 1,6-hexanediol and isosorbide as dihydroxy compounds, which are raw materials for polycarbonate diol.

[0005] However, since various impurities or by-products (hereinafter referred to as "impurities, etc.") are contained in linear aliphatic diols having 3 to 6 carbon atoms during production of the diol, there have been problems such as deterioration of the quality of polycarbonate diol produced using the diol, and deterioration of the quality of the obtained polyurethane product when polyurethane is produced using the polycarbonate diol.

[0006] As a technique for solving such problems, for example, Patent Document 4 discloses a technique in which a 1,6-hexanediol composition is used to produce a polycarbonate diol, and when this is used as a raw material to produce polyurethane, the content of 1,4-dihydroxycyclohexane in the composition is set to 0.1% by weight or less, thereby suppressing a decrease in the polymerization rate during polyurethane production and obtaining a polyurethane with a sufficient molecular weight.

[0007] Patent Document 5 discloses a technique for producing a polyurethane having a sufficient molecular weight by reducing impurities in a 1,6-hexanediol composition to make the ester value of the composition 1 mgKOH / g or less when producing a polycarbonate diol using the composition as a raw material, thereby suppressing a decrease in polymerization rate during polyurethane production.

[0008] Furthermore, Patent Document 6 discloses a technology for suppressing coloration of polyurethane or polyester obtained by producing polyurethane or polyester using a 1,6-hexanediol composition as a raw material by controlling the aldehyde content in the 1,6-hexanediol composition to less than 500 ppm. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2-289616 [Patent Document 2] Japanese Patent Application Publication No. 5-51428 [Patent Document 3] JP 2012-072350 A [Patent Document 4] JP 2001-316312 A [Patent Document 5] International Publication No. 2010 / 047291 [Patent Document 6] Special Publication No. 2013-512293 Summary of the Invention [Problem to be solved by the invention]

[0010] The above-mentioned Patent Documents 4 to 6 focus on the fact that impurities contained in 1,6-hexanediol have an adverse effect on the quality of the obtained polycarbonate diol and on the quality or productivity of polyester or polyurethane produced using the polycarbonate diol, and have a technical idea of ​​reducing the content of impurities in 1,6-hexanediol. For example, in Patent Document 6, which describes the aldehyde content in 1,6-hexanediol, the aldehyde content in 1,6-hexanediol is less than 500 ppm, preferably less than 400 ppm, particularly preferably less than 100 ppm, and particularly preferably less than 50 ppm. Incidentally, Patent Document 6 does not disclose the production of a polycarbonate diol from 1,6-hexanediol and the production of a polyurethane from the produced polycarbonate diol.

[0011] However, Patent Documents 4 to 6 do not mention at all that, by intentionally adding a specific trace component to a linear aliphatic diol having 3 to 6 carbon atoms such as 1,6-hexanediol or 1,4-butanediol, the quality such as color tone of a polycarbonate diol obtained by using the diol can be well maintained, while maintaining polymerization stability when producing a polyurethane from the polycarbonate diol as a raw material, or that the product quality of the obtained polyurethane can be excellent; specifically, the mechanical properties, chemical resistance, and other physical properties of the polyurethane and the mechanical strength can be suppressed.

[0012] The present invention has been made in view of the above problems, and an object of the present invention is to provide a diol-containing composition used in a process for producing a polycarbonate diol, which is capable of producing a polyurethane having excellent mechanical properties and chemical resistance and suppressed variation in the mechanical properties while maintaining the quality such as color tone of the produced polycarbonate diol well. [Means for solving the problem]

[0013] As a result of intensive research into solving the above problems, the present inventors have found that the above problems can be solved by using a diol-containing composition containing a linear aliphatic diol having 3 to 6 carbon atoms, such as 1,6-hexanediol containing an aldehyde, in a production process of a polycarbonate diol, and have thus arrived at the present invention.

[0014] The present invention has been achieved based on these findings, and has the following gist.

[0015] [1] A diol-containing composition used in a process for producing a polycarbonate diol, comprising an aldehyde and a diol (1) represented by the following general formula (1): HO-(CH2) n -OH (1) (In the above general formula (1), n ​​is an integer of 3 to 6.)

[0016] [2] The diol-containing composition according to [1], wherein the diol-containing composition contains the aldehyde in an amount of 1 ppm by mass or more relative to the total mass of the diol-containing composition.

[0017] [3] The diol-containing composition according to [1] or [2], wherein the diol-containing composition contains the aldehyde in an amount of 900 ppm by mass or less based on the total mass of the diol-containing composition.

[0018] [4] The diol-containing composition according to any one of [1] to [3], wherein the content of the diol (1) is 85 mass% or more with respect to 100% total mass of the diol-containing composition.

[0019] [5] The diol-containing composition according to any one of [1] to [4], wherein the diol (1) is at least one selected from 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol.

[0020] [6] The diol-containing composition according to any one of [1] to [5], wherein the aldehyde is a compound having 4 to 6 carbon atoms and one or more aldehyde groups in the molecule.

[0021] [7] The diol-containing composition according to any one of [1] to [6], wherein the diol (1) includes a biomass-derived diol.

[0022] [8] The diol-containing composition according to any one of [1] to [7], wherein the diol (1) is 1,6-hexanediol, and the aldehyde is at least one selected from the group consisting of 6-hydroxyhexanal and adipaldehyde.

[0023] [9] A polycarbonate diol obtained by using the diol-containing composition according to any one of [1] to [8] and a carbonate compound as raw materials.

[0024]

[10] A polyurethane made from the polycarbonate diol described in [9] and an isocyanate compound. Effect of the Invention

[0025] According to the present invention, there is provided a diol-containing composition used in a process for producing a polycarbonate diol, which is capable of producing a polyurethane having excellent mechanical properties and chemical resistance and suppressed variation in the mechanical properties while maintaining the quality such as color tone of the produced polycarbonate diol in a good condition. Furthermore, according to the present invention, there is provided a polycarbonate diol that is made from the diol-containing composition as a raw material, maintains quality such as color tone, and is excellent in mechanical properties and chemical resistance, and can be used to produce polyurethane with reduced variation in the mechanical properties. Furthermore, according to the present invention, there is provided a polyurethane made from the polycarbonate diol as a raw material, which has excellent mechanical properties and chemical resistance and suppressed variation in the mechanical properties. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, the embodiments of the present invention will be described in detail, however, the present invention is not limited to the following embodiments and can be practiced in various modifications within the scope of the gist thereof.

[0027] 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 indicates a partial structure sandwiched between any linking groups in the obtained polymer. It also includes a partial structure at the end of the 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 a different structure by treating the obtained polymer. In this specification, the term "repeating unit" is synonymous with the term "structural unit."

[0028] In this specification, unless otherwise specified, a numerical range expressed with "~" means a range that includes the numerical values ​​before and after "~" as the lower and upper limits, and "A~B" means A or more and B or less.

[0029] In this specification, "including A or B" means "including A," "including B," or "including A and B," unless otherwise specified.

[0030] In this specification, "% by mass" indicates the content of a given component in a total amount of 100% by mass. In this specification, "mass%" and "weight%", "mass ppm" and "weight ppm", and "parts by mass" and "parts by weight" are synonymous. In addition, when simply written as "ppm", it means "ppm by weight".

[0031] In this specification, the term "obtained polycarbonate diol" refers to a polycarbonate diol produced using the diol-containing composition of the present invention and a carbonate compound as raw materials. In this specification, the term "obtained polyurethane" refers to a polyurethane produced using the polycarbonate diol of the present invention and an isocyanate compound as raw materials.

[0032] [Diol-containing composition] The diol-containing composition of the present invention is a diol-containing composition containing an aldehyde and a diol (1) described below. Hereinafter, the "aldehyde" according to the present invention may be referred to as "aldehyde (A)". The diol-containing composition of the present invention may be substantially composed of a trace amount of aldehyde (A) and a diol, and therefore may be referred to as a "diol." However, the diol-containing composition of the present invention is not composed only of a diol, and therefore is referred to as a "diol-containing composition."

[0033] Furthermore, since the diol-containing composition of the present invention contains the aldehyde (A), by using the diol-containing composition as a raw material in the process of producing a polycarbonate diol, it is possible to obtain a polycarbonate diol whose quality such as color tone is well maintained to an extent that does not cause problems in practical use. Furthermore, by using the polycarbonate diol obtained from the diol-containing composition of the present invention as a raw material in a process for producing polyurethane, it is possible to obtain polyurethane that is excellent in mechanical properties and chemical resistance and has reduced variation in the mechanical properties.

[0034] <Diol (1)> The diol (1) in the present invention is a compound represented by the following general formula (1), and is one component constituting the diol-containing composition of the present invention. HO-(CH2) n -OH (1) (In the above general formula (1), n ​​is an integer of 3 to 6.)

[0035] The diol-containing composition of the present invention contains the diol (1), and thus the polyurethane obtained by using the polycarbonate diol produced from the diol-containing composition of the present invention as a raw material (hereinafter, may be simply referred to as "obtained polyurethane") has good mechanical properties and chemical resistance.

[0036] The content of diol (1) in the diol-containing composition of the present invention is not particularly limited, and from the viewpoint of improving the handleability of the obtained polycarbonate diol and the flexibility and low-temperature properties of the obtained polyurethane, it is preferably 85% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 96% by mass or more, based on 100% of the total mass of the diol-containing composition. On the other hand, the upper limit of the content of diol (1) in the diol-containing composition is not particularly limited, and it can be preferably less than 100% by mass, more preferably 99% by mass or less, even more preferably 98% by mass or less, and particularly preferably 97% by mass or less, based on 100% of the total mass of the diol-containing composition. The upper and lower limits can be combined arbitrarily. For example, the content of diol (1) in the diol-containing composition of the present invention can be preferably 85% by mass or more and less than 100% by mass, more preferably 90% by mass or more and 99% by mass or less, further preferably 95% by mass or more and 98% by mass or less, and particularly preferably 96% by mass or more and 97% by mass or less, based on 100% by mass of the total diol-containing composition.

[0037] In the diol-containing composition of the present invention, the diol (1) is not particularly limited, and may be appropriately selected from known dihydroxy compounds used as raw materials for polycarbonate diols. Specific examples thereof include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol. The diol (1) may be used alone or in combination of two or more kinds.

[0038] The diol (1) may contain a compound (1-1) represented by the following general formula (1-1), that is, 1,6-hexanediol, as necessary. HO-(CH2)6-OH (1-1) When the diol (1) contains 1,6-hexanediol, the mechanical properties and chemical resistance of the resulting polyurethane are improved.

[0039] In such a case, the content ratio of the compound (1-1) in the diol (1) is not particularly limited, and is preferably 10% by mass or more, more preferably 30% by mass or more, even more preferably 50% by mass or more, and particularly preferably 70% by mass or more, based on 100% of the total mass of the diol (1), from the viewpoint of improving the handleability of the polycarbonate diol and the flexibility and low-temperature properties of the obtained polyurethane. This content ratio can also be 90% by mass or more. On the other hand, the upper limit of the content ratio of the diol (1-1) in the diol (1) is not particularly limited, and may be 100% by mass, or may be preferably less than 100% by mass, more preferably 99% by mass or less, even more preferably 98% by mass or less, and particularly preferably 97% by mass or less, based on 100% of the total mass of the diol (1). The upper and lower limits can be combined arbitrarily. For example, the content of the compound (1-1) in the diol (1) can be 100% by mass, or preferably 10% by mass or more and less than 100% by mass, more preferably 30% by mass or more and 99% by mass or less, further preferably 50% by mass or more and 98% by mass or less, and particularly preferably 70% by mass or more and 97% by mass or less, based on the total mass of the polycarbonate diol (100%).

[0040] The diol-containing composition of the present invention can achieve the Sustainable Development Goals (SDGs) by using a diol composition containing a biomass-derived diol (1) as the diol (1). Specifically, a biomass-derived diol (1) alone or a mixture containing a biomass-derived diol (1) and a fossil fuel-derived diol (1) can be used. The biomass-derived diol (1) is a diol (1) derived from non-edible biomass and / or non-fossil fuel.

[0041] 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 trees and broad-leaved trees, bioethanol and biodiesel obtained from herbaceous biomass such as corn and sugarcane stalks, soybeans and rapeseed, and waste oil derived from plants. In the present invention, the term "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 of non-fossil fuels include, but are not limited to, methane and sugar ethanol obtained from firewood, charcoal, dried livestock manure, etc.

[0042] In the present invention, the diol (1) derived from a fossil fuel refers to at least one selected from the group consisting of diol (1) derived from petroleum, diol (1) derived from coal, and diol (1) derived from natural gas.

[0043] The above-mentioned biomass-derived diol (1) may contain the above-mentioned aldehyde (A) depending on its origin. Therefore, the above-mentioned effects of the present invention can be obtained by controlling the content of the aldehyde (A) in the compound (1) to produce the diol-containing composition of the present invention, or by controlling the content of the aldehyde (A) in the diol-containing composition produced using the compound (1).

[0044] For example, in the diol-containing composition of the present invention, 1,6-hexanediol derived from fossil fuels can be used alone as the compound (1-1). Alternatively, the diol-containing composition of the present invention uses, as the compound (1-1), 1,6-hexanediol including biomass-derived 1,6-hexanediol, specifically, biomass-derived 1,6-hexanediol alone, or a mixture containing biomass-derived 1,6-hexanediol and fossil fuel-derived 1,6-hexanediol, thereby making it possible to achieve the Sustainable Development Goals (SDGs). Biomass-derived 1,6-hexanediol is 1,6-hexanediol derived from non-edible biomass and / or non-fossil fuels.

[0045] In the present invention, 1,6-hexanediol derived from a fossil fuel refers to at least one selected from 1,6-hexanediol derived from petroleum, 1,6-hexanediol derived from coal, and 1,6-hexanediol derived from natural gas.

[0046] The above-mentioned biomass-derived 1,6-hexanediol may contain the above-mentioned aldehyde (A) depending on its origin. Therefore, the above-mentioned effects of the present invention can be obtained by controlling the content of the aldehyde (A) in the 1,6-hexanediol to produce the diol-containing composition of the present invention, or by controlling the content of the aldehyde (A) in the polycarbonate diol produced using the 1,6-hexanediol.

[0047] <Aldehyde (A)> The aldehyde (A) in the present invention is one component constituting the diol-containing composition of the present invention. The aldehyde (A) in the present invention is not particularly limited, and any known aldehyde compound or an aldehyde compound in which the hydroxy group of the diol (1) is replaced with an aldehyde group can be used.

[0048] An aldehyde group may react with a hydroxy group to convert to an acetal group. Therefore, the aldehyde (A) in the present invention also includes an acetal compound in which the aldehyde group of the aldehyde compound is replaced with an acetal group (hereinafter, sometimes referred to as "acetal (A)"). That is, the content of the aldehyde (A) in the present invention means the total content of the aldehyde compound and the acetal (A) which is an acetal modified product thereof.

[0049] Examples of the acetal (A) include an acetal compound (a) in which an aldehyde group of the aldehyde (A) reacts with a hydroxy group to form an acetal group; an acetal compound (b) in which two molecules of a monohydroxy compound react with one aldehyde group of the aldehyde (A); an acetal compound (c) in which one molecule of a dihydroxy compound reacts with one aldehyde group of the aldehyde (A); and a hemiacetal compound (d) in which one molecule of a monohydroxy compound reacts with one aldehyde group of the aldehyde (A). The acetal (A) may be one of these or two or more of them.

[0050] The aldehyde (A) is produced as a by-product in a hydrogenation reaction step in producing the diol (1) by hydrogenating a carboxylic acid having 3 to 6 carbon atoms or an ester derivative of the carboxylic acid, which is a precursor of the diol (1). The type of the “precursor of diol (1)” is not particularly limited. For example, in the diol (1) represented by the general formula (1), When n=3, malonic acid or a malonic acid ester; When n=4, succinic acid or a succinate ester; When n=5, glutaric acid or glutaric acid esters; When n=6 (the compound (1-1)), adipic acid or an adipic acid ester; Examples include:

[0051] In the production step of the diol (1), methods for increasing the amount of the by-product aldehyde (A) can be used, such as reducing the amount of catalyst used in the hydrogenation reaction, shortening the residence time, or making the hydrogen pressure too low. Conversely, in the production stage of the diol (1), methods for reducing the by-product aldehyde (A) can be used such as increasing the amount of catalyst used in the hydrogenation reaction, lengthening the residence time, or excessively increasing the hydrogen pressure.

[0052] In addition, since the acetal (A) requires a hydrogenation catalytic ability different from that of the aldehyde (A), the hydrogenation reaction is difficult to carry out with a hydrogenation catalyst for the aldehyde (A), and the acetal (A) may remain in the diol (1). Furthermore, in the production of the diol (1), the diol (1) is usually purified by distillation after the hydrogenation reaction step, but even in the distillation stage, the acetal (A) produced as a by-product in the hydrogenation reaction step may decompose into the aldehyde (A) and be mixed into the purified diol (1).Also, the aldehyde (A) may react with a hydroxy group to produce the acetal (A), which may be mixed into the diol (1). In general, the aldehyde (A) produced as a by-product in the production process of a dihydroxy compound having a small number of carbon atoms can be relatively easily separated by distillation purification. However, when the boiling points of the diol (1) and the aldehyde (A) are close to each other and it is difficult to separate them as acetal (A), the aldehyde (A) and / or acetal (A) tend to remain in the diol (1) even after distillation purification.

[0053] The type of aldehyde (A) in the present invention is not particularly limited, and examples thereof include compounds having 4 to 6 carbon atoms and having at least one, preferably at most six, aldehyde groups in the molecule. When n=3, monoaldehyde compounds such as 3-hydroxypropanal, dialdehyde compounds such as malondialdehyde; When n=4, monoaldehyde compounds such as 4-hydroxybutanal, dialdehyde compounds such as succinaldehyde; When n=5, monoaldehyde compounds such as 5-hydroxypentanal, dialdehyde compounds such as glutaraldehyde; When n=6 (the compound (1-1)), examples of the compound include monoaldehyde compounds such as 6-hydroxyhexanal, and dialdehyde compounds such as adipaldehyde.

[0054] Among these, from the viewpoint of the mechanical strength and chemical resistance of the obtained polyurethane, the diol-containing composition of the present invention is preferably a diol-containing composition in which the diol (1) is 1,6-hexanediol and the aldehyde is at least one selected from 6-hydroxyhexanal and adipaldehyde.

[0055] <Aldehyde (A) content> The content of the aldehyde (A) in the diol-containing composition of the present invention refers to the content of the aldehyde (A) in the composition. Furthermore, in the case where the diol-containing composition contains the acetal (A), the content of the aldehyde (A) in the diol-containing composition of the present invention refers to the total content of the aldehyde (A) and the acetal (A) in the composition.

[0056] The lower limit of the content of the aldehyde (A) in the diol-containing composition is not particularly limited, and from the viewpoints of excellent mechanical properties and chemical resistance of the obtained polyurethane and suppression of variation in the mechanical properties, and further, economic efficiency for reducing the aldehyde (A), the lower limit is preferably 1 ppm by mass or more, more preferably 5 ppm by mass or more, even more preferably 15 ppm by mass or more, particularly preferably 50 ppm by mass or more, and most preferably more than 50 ppm by mass, relative to the total mass of the diol-containing composition. On the other hand, the upper limit of the content of the aldehyde (A) is not particularly limited, and is preferably 900 mass ppm or less based on the total mass of the diol-containing composition from the viewpoint of maintaining good mechanical properties and chemical resistance of the obtained polyurethane. If the content of the aldehyde (A) is too high, depending on the production conditions when producing polyurethane using the polycarbonate diol made from the diol-containing composition of the present invention as a raw material, the aldehyde (A) reacts with the hydroxyl group terminal of the polycarbonate diol, or reacts with the isocyanate compound used as a raw material for the polyurethane, forming a crosslinked structure in the polyurethane during polyurethane polymerization, and gelation occurs, resulting in impaired polymerization stability. The upper limit of the content of the aldehyde (A) is more preferably 700 mass ppm or less, even more preferably 500 mass ppm or less, and particularly preferably 300 mass ppm or less. The upper and lower limits can be combined arbitrarily.For example, the content ratio of the aldehyde (A) contained in the diol-containing composition of the present invention is preferably 1 mass ppm or more and 900 mass ppm or less, more preferably 5 mass ppm or more and 700 mass ppm or less, even more preferably 15 mass ppm or more and 500 mass ppm or less, and particularly preferably 50 mass ppm or more and 300 mass ppm or less, based on the total mass of the diol-containing composition.

[0057] In the diol-containing composition of the present invention, the specific method for controlling the content ratio of the aldehyde (A) 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 diol-containing composition of the present invention described later based on well-known techniques.

[0058] [Polycarbonate diol] The polycarbonate diol of the present invention is a polycarbonate diol compound produced from the diol-containing composition of the present invention and a carbonate compound described below as raw materials. The polycarbonate diol of the present invention can contain a structural unit (1) derived from a diol (1) represented by the following general formula (1). HO-(CH2) n -OH (1) (In the above general formula (1), n ​​is an integer of 3 to 6.)

[0059] The polycarbonate diol of the present invention contains the structural unit (1) derived from the diol (1), and thus the obtained polyurethane has good mechanical properties and chemical resistance.

[0060] In the polycarbonate diol of the present invention, the diol (1) is not particularly limited, and a known dihydroxy compound used as a raw material for polycarbonate diol can be appropriately selected and used. Specific examples thereof include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol. The diol (1) may be used alone or in combination of two or more kinds.

[0061] 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 polyurethane obtained, it is preferably 40% by mass or more, more preferably 60% by mass or more, even more preferably 75% by mass or more, and particularly preferably 80% by mass or more, based on the total mass 100% of the polycarbonate diol. On the other hand, the upper limit of the content of the structural unit (1) is not particularly limited, and may be 100% by mass or less. Alternatively, from the viewpoint of maintaining good chemical resistance of the polyurethane obtained, it is more preferably 98% by mass or less, more preferably 95% by mass or less, and particularly preferably 90% by mass or less, based on the total mass 100% of the composition. The 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 40% by mass or more and 100% by mass or less, more preferably 60% by mass or more and 98% by mass or less, further preferably 75% by mass or more and 95% by mass or less, and particularly preferably 80% by mass or more and 90% by mass or less, based on 100% by mass of the total mass of the polycarbonate diol.

[0062] Since the polycarbonate diol of the present invention is produced using the diol-containing composition of the present invention as a raw material, it is possible to maintain the quality such as color tone well.

[0063] Furthermore, since the polycarbonate diol of the present invention is produced by using the diol-containing composition of the present invention containing the aldehyde (A) as a raw material, the mechanical strength and chemical resistance of the obtained polyurethane are more excellent, and it is possible to stably produce a high-quality polyurethane with reduced variation in the mechanical strength.

[0064] Furthermore, in the polycarbonate diol of the present invention, the diol (1) forming the structural unit (1) can include a compound (1-1) represented by the following general formula (1-1), that is, 1,6-hexanediol. HO-(CH2)6-OH (1-1)

[0065] When the polycarbonate diol in the present invention contains the compound (1-1) represented by the formula (1-1), i.e., 1,6-hexanediol, as the diol (1) forming the structural unit (1), the structural unit (1-1) is represented, for example, by the following formula (1-1').

[0066] [ka]

[0067] In such a case, the content ratio of the compound (1-1) in the diol (1) forming the structural unit (1) is not particularly limited, and from the viewpoint of improving the handleability of the obtained polycarbonate diol and the flexibility and low-temperature properties of the obtained polyurethane, it is preferably 10% by mass or more, more preferably 30% by mass or more, even more preferably 50% by mass or more, and particularly preferably 70% by mass or more, based on 100% of the total mass of the diol (1). This content ratio can also be 90% by mass or more. On the other hand, the upper limit of the content ratio of the compound (1-1) in the diol (1) is not particularly limited, and may be 100% by mass, or may be preferably less than 100% by mass, more preferably 99% by mass or less, even more preferably 98% by mass or less, and particularly preferably 97% by mass or less, based on 100% of the total mass of the diol (1). The above upper and lower limits can be combined in any manner.

[0068] <Diol (2)> The diol (2) in the present invention is a compound represented by the following general formula (2), and can be used as a raw material for constituting the polycarbonate diol in the present invention, if necessary. That is, in the polycarbonate diol of the present invention, the polycarbonate diol can contain a structural unit (2) derived from a diol (2) represented by the following general formula (2). H.O.R. 1 -OH (2) (In the above general formula (2), R 1 represents a divalent alkylene group having 3 to 20 carbon atoms, which may have a substituent. However, the compound (2) represented by the above general formula (2) does not include the compound (1) represented by the above general formula (1).

[0069] In the formula (2), R 1 represents a substituted or unsubstituted divalent alkylene group having 3 to 20 carbon atoms.

[0070] The structural unit (2) derived from the compound represented by the formula (2) is represented by, for example, the following formula (2').

[0071] [ka]

[0072] In the formula (2), R 1 In the formula (2), R may be one type or a plurality of types. 1 is a substituted or unsubstituted divalent alkylene group having 3 to 20 carbon atoms. R 1 The carbon atom in the main chain constituting the alkylene group is preferably a secondary, tertiary or quaternary carbon atom, and more preferably a secondary carbon atom.

[0073] In the polycarbonate diol of the present invention, by using an aliphatic dihydroxy compound having no aromatic ring structure in the molecular structure, such as the diol (2), the handleability of the polycarbonate diol and the flexibility and chemical resistance of the obtained polyurethane can be excellent.

[0074] The lower limit of the content of the structural unit (2) in 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 flexibility and chemical resistance of the obtained polyurethane, it is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 25% by mass or more, based on 100% of the total mass of the polycarbonate diol. On the other hand, the upper limit of the content of the structural unit (2) is not particularly limited, and from the viewpoint of maintaining good handleability of the polycarbonate diol and good flexibility and low-temperature properties of the obtained polyurethane, it is preferably 95% by mass or less, more preferably 75% by mass or less, and even more preferably 50% by mass or less, based on 100% of the total mass of the polycarbonate diol. The upper and lower limits can be combined in any combination. For example, the content of the structural unit (2) in the polycarbonate diol of the present invention is preferably 5% by mass or more and 95% by mass or less, more preferably 10% by mass or more and 75% by mass or less, and even more preferably 25% by mass or more and 50% by mass or less, based on 100% by mass of the total mass of the polycarbonate diol.

[0075] In the polycarbonate diol of the present invention, the diol (2) is not particularly limited, and examples thereof include 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,3-butanediol, 2-methyl-1,4-butanediol, 1,7-heptanediol, 1,8-octanediol, 2-methyl-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, 1,12-octadecanediol, and 1,20-eicosanediol. Among these, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,3-butanediol, 2-methyl-1,4-butanediol, and 1,10-decanediol are preferred, and 1,10-decanediol is more preferred, because the resulting polyurethane has an excellent balance of flexibility, low-temperature properties, and chemical resistance. These diols (2) may be used alone or in combination of two or more.

[0076] <Diol (3)> The diol (3) in the present invention is a dihydroxy compound having a moiety represented by the following general formula (3) as a part of its structure, and can be used as a raw material for constituting the polycarbonate diol in the present invention, if necessary. That is, in the polycarbonate diol of the present invention, the polycarbonate diol can contain a structural unit (3) derived from a diol (3) having a moiety represented by the following general formula (3) in a part of its structure. -(CH2-O)- (3) (However, this does not include the case where the moiety represented by the above general formula (3) is a part of -CH2-OH.)

[0077] In the polycarbonate diol of the present invention, by using a dihydroxy compound having a moiety represented by the structural unit (3) as a part of the structure, such as the diol (3), the handleability of the polycarbonate diol and the flexibility and low-temperature properties of the obtained polyurethane can be excellent.

[0078] The lower limit of the content of the structural unit (3) in the polycarbonate diol of the present invention is not particularly limited, and from the viewpoint of the handleability of the polycarbonate diol and the flexibility and low-temperature properties of the obtained polyurethane, it is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 25% by mass or more, based on 100% of the total mass of the polycarbonate diol. On the other hand, the upper limit of the content of the structural unit (3) is not particularly limited, and from the viewpoint of maintaining good handleability of the polycarbonate diol and good heat resistance and strength of the obtained polyurethane, it is preferably 95% by mass or less, more preferably 75% by mass or less, and even more preferably 50% by mass or less, based on 100% of the total mass of the composition. The upper and lower limits can be combined in any way. For example, the content of the structural unit (3) in the polycarbonate diol of the present invention is preferably 5% by mass or more and 95% by mass or less, more preferably 10% by mass or more and 75% by mass or less, and even more preferably 25% by mass or more and 50% by mass or less, based on 100% by mass of the total mass of the polycarbonate diol.

[0079] In the polycarbonate diol of the present invention, the diol (3) is not particularly limited, and examples thereof include oxyalkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol; 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-methylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-isopropylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-isobutylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-tert-butylphenyl)fluorene, 9,9-bis(4-(2 9,9-bis(4-(2-hydroxyethoxy)-3-cyclohexylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3,5-dimethylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-tert-butyl-6-methylphenyl)fluorene, 9,9-bis(4-(3-hydroxy-2,2-dimethylpropoxy)phenyl)fluorene, and other compounds having an aromatic group on the side chain and an ether group bonded to the aromatic group on the main chain; anhydrous sugar alcohols represented by dihydroxy compounds represented by the following general formula (4); and compounds having a cyclic ether structure such as spiro glycol represented by the following general formula (5). These diols (3) may be used alone or in combination of two or more.

[0080] [ka]

[0081] [ka]

[0082] Of these diols (3), it is preferable to use a dihydroxy compound that does not have an aromatic ring structure from the viewpoint of the light resistance of the resulting polyurethane.

[0083] Specific examples of anhydrous sugar alcohols typified by the dihydroxy compound represented by the above general formula (4) include at least one selected from isosorbide, isomannide, and isoidet, which are stereoisomeric. These may be used alone or in combination of two or more. Among them, isosorbide obtained by dehydration condensation of sorbitol produced from various starches, which are abundant and easily available as a plant-derived resource, is most preferred from the viewpoints of availability and ease of production, light resistance, optical properties, moldability, heat resistance, and achievement of the Sustainable Development Goals (SDGs).

[0084] <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 good mechanical properties of the obtained 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 keeping the viscosity of the polycarbonate diol of the present invention to a certain level and maintaining good handleability, and from the viewpoint of maintaining good chemical resistance of the obtained 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 combined in any manner.

[0085] <Aldehyde (A) content> The polycarbonate diol of the present invention is made from the diol-containing composition of the present invention containing the aldehyde (A) as a raw material, and therefore usually contains the aldehyde (A) derived from the diol-containing composition of the present invention. The content ratio of the aldehyde (A) in the polycarbonate diol of the present invention refers to the content ratio of the aldehyde (A) in the polycarbonate diol. Furthermore, when the polycarbonate diol contains the acetal (A), the content of the aldehyde (A) in the polycarbonate diol of the present invention refers to the total content of the aldehyde (A) and the acetal (A) in the polycarbonate diol. The polycarbonate diol of the present invention is also called a "polycarbonate diol composition" because it contains a polycarbonate diol and an aldehyde (A). However, since the content of the aldehyde (A) in the polycarbonate diol of the present invention is very small as described below, it is called a "polycarbonate diol" in this specification.

[0086] The upper limit of the content of the aldehyde (A) in the polycarbonate diol of the present invention is not particularly limited, and from the viewpoint of a good color tone of the polycarbonate diol and good polymerization stability during polyurethane polymerization, and further from the viewpoint of maintaining good mechanical properties and chemical resistance of the obtained polyurethane, the upper limit is preferably 440 ppm by mass or less, more preferably 400 ppm by mass or less, further preferably 350 ppm by mass or less, and particularly preferably 300 ppm by mass or less, relative to the total mass of the polycarbonate diol. On the other hand, the lower limit of the content ratio of the aldehyde (A) in the polycarbonate diol is not particularly limited, and from the viewpoint of the polyurethane obtained using this polycarbonate diol being excellent in mechanical properties and chemical resistance and suppressing variation in mechanical properties, the content ratio of the aldehyde (A) in the polycarbonate diol of the present invention is preferably 1 ppm by mass or more, more preferably 5 ppm by mass or more, further preferably 15 ppm by mass or more, and particularly preferably 50 ppm by mass or more, based on the total mass of the polycarbonate diol. The upper and lower limits can be combined arbitrarily. For example, the content of the aldehyde (A) in the polycarbonate diol of the present invention is preferably 1 mass ppm or more and 440 mass ppm or less, more preferably 5 mass ppm or more and 400 mass ppm or less, further preferably 15 mass ppm or more and 350 mass ppm or less, and particularly preferably 50 mass ppm or more and 300 mass ppm or less, based on the total mass of the polycarbonate diol.

[0087] The aldehyde (A) in the polycarbonate diol of the present invention includes both the aldehyde (A) that is free in the polycarbonate diol of the present invention and the aldehyde (A) that is bonded or associated with the polycarbonate diol or that is included as part of the structure of the polycarbonate diol.

[0088] The form of the "aldehyde (A) bonded to or associated with a polycarbonate diol or contained as a part of the structure of the polycarbonate diol" is not particularly limited, and examples thereof include a form in which a hydroxy group or an amino group contained in the aldehyde (A) reacts to form a carbonate bond or a urethane bond in the polycarbonate diol.

[0089] [Production method of 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), International Publication No. WO 2015 / 199070, etc. can be used.

[0090] As a specific embodiment of the method for producing the polycarbonate diol of the present invention, a method in which the diol-containing composition of the present invention containing the aldehyde (A) and a carbonate compound described later are polycondensed by an ester exchange reaction in the presence of a catalyst described later to obtain a polycarbonate diol can be mentioned.

[0091] <Carbonate compounds> The carbonate compound (sometimes referred to as "carbonic acid diester") that can be used 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 known carbonate compounds used in the synthesis of polycarbonate diols, such as dialkyl carbonates, diaryl carbonates, and alkylene carbonates, and can be appropriately selected by a person skilled in the art depending on the use of the polycarbonate diol, production conditions, and the like. For example, from the viewpoint of reactivity between the diol (1) and the diol (2) and diol (3) used as needed and the carbonate compound, the carbonate compound is preferably a diaryl carbonate, or from the viewpoint of economy, the carbonate compound is preferably a dialkyl carbonate or an alkylene carbonate. Specific examples of the carbonate compound include dimethyl carbonate, diethyl carbonate, dibutyl carbonate, diphenyl carbonate, and ethylene carbonate. The amount of the carbonate compound used is not particularly limited, and can be appropriately optimized by a person skilled in the art in accordance with known techniques, for example, the conditions described in WO 2015 / 199070.

[0092] <Catalyst> In the method for producing the polycarbonate diol of the present invention, when the dihydroxy compound composition including the diol-containing composition of the present invention and a carbonate compound are polycondensed by transesterification to obtain the polycarbonate diol, a known transesterification catalyst (hereinafter, sometimes referred to as "catalyst") used in the synthesis of polycarbonate diol can be used as a catalyst for promoting the transesterification reaction. In that case, if an excessive amount of catalyst remains in the obtained polycarbonate diol, the reaction may be inhibited or excessively promoted when the polycarbonate diol is used to produce a polyurethane. The type of the catalyst and the amount of the catalyst remaining in the polycarbonate diol are not particularly limited. For example, the conditions described in WO 2015 / 199070 can be appropriately optimized by a person skilled in the art according to known techniques.

[0093] <Catalyst deactivator> As mentioned above, when a catalyst is used in the polymerization reaction, the catalyst usually remains in the obtained polycarbonate diol, and the remaining catalyst may cause an increase in molecular weight or a change in composition when the polycarbonate diol is heated, or the polyurethane reaction may become uncontrollable. In order to suppress the influence of the remaining catalyst, if necessary, a catalyst deactivator such as a phosphorus compound or the like can be added in an amount approximately equivalent in moles 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 of the heat treatment are not particularly limited. For example, the conditions described in WO 2015 / 199070 can be appropriately optimized by a person skilled in the art according to known techniques.

[0094] [Polyurethane] The polyurethane of the present invention is produced using the polycarbonate diol of the present invention and an isocyanate compound described below as raw materials. The method for producing the polyurethane of the present invention is not particularly limited, and a person skilled in the art can appropriately optimize and use known polyurethane reaction conditions described in, for example, WO 2015 / 016261, WO 2018 / 088575, etc. in accordance with known techniques. 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, a polyisocyanate described below, and a chain extender described below, which is further used as needed, at a temperature range from room temperature to 200°C.

[0095] 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 end, and then adding a chain extender to react with the prepolymer to increase the polymerization degree of the polymer.

[0096] <Polyisocyanate> As the polyisocyanate used in the production of the polyurethane of the present invention, any known polyisocyanate used in the production of polyurethanes can be used. The polyisocyanate is not particularly limited, and examples thereof include various aliphatic, alicyclic, or aromatic polyisocyanate compounds described in WO 2015 / 016261 and WO 2018 / 088575.

[0097] Specific examples of the diisocyanates include known aliphatic diisocyanates such as tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, and 2,2,4-trimethylhexamethylene diisocyanate; known alicyclic diisocyanates such as 1,4-cyclohexane diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and 1,3-bis(isocyanatemethyl)cyclohexane; and known aromatic diisocyanates such as xylylene diisocyanate, 4,4'-diphenyl diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and 4,4'-diphenyldimethylmethane diisocyanate. These may be used alone or in combination of two or more.

[0098] Among these, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate and isophorone diisocyanate are preferred in that the resulting polyurethane has a good balance of physical properties and that they are available industrially in large quantities at low cost.

[0099] <Chain extender> As the chain extender used in the production of the polyurethane of the present invention, any known chain extender used in the production of polyurethanes can be used. The chain extender is not particularly limited, and examples thereof include low molecular weight polyols, amines, water, and the like described in WO 2015 / 016261 and WO 2018 / 088575. Specifically, straight-chain diols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol; branched-chain diols such as 2-methyl-1,3-propanediol and 2,2-dimethyl-1,3-propanediol; diols having an ether group such as diethylene glycol and propylene glycol; diols having an alicyclic structure such as 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and 1,4-dihydroxyethylcyclohexane; xylylene glycol, 1,4-dihydroxyethylcyclohexane, and the like. Examples of the chain extenders include diols having an aromatic group such as hydroxyethylbenzene and 4,4'-methylenebis(hydroxyethylbenzene); polyols such as glycerin, trimethylolpropane and pentaerythritol; hydroxyamines such as N-methylethanolamine and N-ethylethanolamine; polyamines such as ethylenediamine, 1,3-diaminopropane, hexamethylenediamine, triethylenetetramine, diethylenetriamine, isophoronediamine, 4,4'-diaminodicyclohexylmethane, 2-hydroxyethylpropylenediamine, 4,4'-diphenylmethanediamine, xylylenediamine, diphenyldiamine, hydrazine and piperazine; and water. These chain extenders may be used alone or in combination of two or more.

[0100] Among these, ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,4-cyclohexanedimethanol, 1,4-dihydroxyethylcyclohexane, ethylenediamine, 1,3-diaminopropane, isophoronediamine, and 4,4'-diaminodicyclohexylmethane are preferred, in that they give rise to a favorable balance of physical properties in the resulting polyurethane and are available in large quantities industrially at low cost.

[0101] <Chain stopper> When producing the polyurethane of the present invention, a known chain terminator used in the production of polyurethanes can be used, if necessary, for the purpose of controlling the molecular weight of the polyurethane. The chain terminator is not particularly limited, and examples thereof include compounds having one active hydrogen group, as described in WO 2015 / 016261 and WO 2018 / 088575. Specific examples include monohydric alcohols such as methanol, ethanol, propanol, butanol, and hexanol, and secondary amines such as diethylamine, dibutylamine, di-n-propylamine, n-butylamine, monoethanolamine, and diethanolamine. These may be used alone or in combination of two or more.

[0102] <Catalyst> When producing the polyurethane of the present invention, a known catalyst used in the production of 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., described in WO 2015 / 016261 and WO 2018 / 088575 can be used.

[0103] <Solvent> When producing the polyurethane of the present invention, a solvent may be used, if necessary. The solvent is not particularly limited, and examples thereof include the solvents described in WO 2015 / 016261 and WO 2018 / 088575. Specific examples include dimethylformamide, diethylformamide, dimethylacetamide, dimethylsulfoxide, tetrahydrofuran, methyl isobutyl ketone, dioxane, cyclohexanone, benzene, toluene, ethyl cellosolve, etc. These may be used alone or in combination of two or more.

[0104] <Amount / How to 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.

[0105] <Polyurethane weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn)> The lower limit of the weight average molecular weight (Mw) of the polyurethane of the present invention is not particularly limited, and from the viewpoint of obtaining good mechanical properties and chemical resistance of the polyurethane obtained, it is preferably 50,000 or more, more preferably 100,000 or more, and even more preferably 150,000 or more. On the other hand, the upper limit of the weight average molecular weight (Mw) is not particularly limited, and from the viewpoint of maintaining good chemical resistance of the polyurethane obtained, it is preferably 500,000 or less, more preferably 300,000 or less, and even more preferably 200,000 or less. The above upper and lower limits can be combined arbitrarily.

[0106] The lower limit of the molecular weight distribution (Mw / Mn) of the polyurethane of the present invention is not particularly limited, and from the viewpoint of obtaining good mechanical properties and chemical resistance of the polyurethane obtained, it is preferably 1.50 or more, more preferably 2.00 or more, and even more preferably 2.50 or more. On the other hand, the upper limit of the molecular weight distribution (Mw / Mn) is not particularly limited, and from the viewpoint of maintaining good mechanical properties and chemical resistance of the polyurethane obtained, it is preferably 4.00 or less, more preferably 3.00 or less, and even more preferably 2.90 or less. The above upper and lower limits can be combined arbitrarily.

[0107] The weight average molecular weight (Mw) and the molecular weight distribution (Mw / Mn) are measured by gel permeation chromatography (GPC measurement), and the measurement conditions are as described in the Examples section below.

[0108] <Applications of polyurethane> The polyurethane of the present invention is excellent in mechanical properties and chemical resistance, has suppressed variation in the mechanical properties, and has good heat resistance and weather resistance. Therefore, the polyurethane 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.

[0109] In particular, when the polyurethane of the present invention is used in applications such as active energy radiation curable polymer compositions, artificial leather, synthetic leather, paints such as water-based polyurethane paints, coating agents, elastic fibers, pressure sensitive adhesives, and adhesives, it has a good balance of chemical resistance, flexibility, heat resistance, and weather resistance, and therefore can impart good properties such as high durability in areas that come into contact with human skin or where cosmetic agents or disinfectant alcohol are used, sufficient flexibility, and resistance to physical impacts, etc. In addition, it can be suitably used in automotive applications requiring heat resistance and outdoor applications requiring weather resistance.

[0110] [Effects] Since the diol-containing composition of the present invention contains the aldehyde (A), the variation in mechanical properties of the resulting polyurethane is suppressed. Although the reason for this is not clear, it is presumed to be as follows. According to the study by the present inventors, when aldehyde (A) is contained in a polycarbonate diol produced from a diol-containing composition containing aldehyde (A) or a polyurethane obtained from the polycarbonate diol, the aldehyde (A) reacts with a compound having a hydroxyl group such as diol (1) to generate an acetal. The acetal reacts with a hydroxyl group or an amino group of the polyurethane to form a branched structure in the polyurethane structure. It was found that the presence of a branched structure in the polyurethane structure improves the viscosity of the polyurethane or a composition containing polyurethane. As a result, it is possible to efficiently improve the uniformity of the polyurethane composition by a stirring operation, and it is presumed that the coating stability and molding stability of the polyurethane or a composition containing polyurethane are improved by appropriately improving the viscosity, and the dimensional stability of the obtained film-like material, fiber-like material, and other molded products is improved, thereby suppressing the variation in mechanical properties of the obtained polyurethane product.

[0111] Furthermore, since the diol-containing composition of the present invention contains an aldehyde (A), the resulting polyurethane has good mechanical properties and chemical resistance, and the balance between the two is excellent. Although the reason for this is unclear, it is presumed to be as follows. According to the study by the present inventors, when polyurethane is polymerized using a polycarbonate diol made from a diol-containing composition containing an aldehyde (A), a part of the aldehyde (A) forms a branched structure in the polyurethane structure as described above. As a result of the formation of the branched structure, it was found that the molecular weight distribution of the polyurethane obtained becomes wider, and the high molecular weight component and crosslinked component of the polyurethane increase. As a result, it is presumed that the breaking strength, breaking elongation, and chemical resistance of the polyurethane obtained are improved. EXAMPLES

[0112] The present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention is not limited to these examples as long as the gist of the present invention is not exceeded.

[0113] [Evaluation method] In the following, the evaluation methods for each physical property value are as follows.

[0114] <Content of aldehyde (A) in diol-containing composition> The content of aldehyde (A) in the diol-containing composition containing 1,6-hexanediol as diol (1) used in the examples and comparative examples was measured according to the following procedure. In this evaluation, "aldehyde (A)" refers to 6-hydroxyhexanal, and the definition of "content of aldehyde (A)" is as described above in the explanation of aldehyde (A). In this evaluation, "aldehyde (A) in a 1,6-hexanediol composition" means aldehyde (A) in a 1,6-hexanediol composition containing 1,6-hexanediol as a main component and aldehyde (A) as a minor component. "Containing as a main component" means that the component is contained in an amount of 85.0% by mass or more relative to 100% by mass of the total mass of the composition. The diol-containing composition was dissolved in CDCl3, and the measurement was performed using a nuclear magnetic resonance spectrometer (400 MHz, manufactured by JEOL Ltd., model name: ECZ-400) under the conditions of a measurement temperature of 30°C and an accumulation number of 32. 1 H-NMR measurements were performed. Obtained 1 From the H-NMR measurement results, the aldehyde group in aldehyde (A) (6-hydroxyhexanal) present at δ 9.80-9.75 ppm 1 The content (unit: mass%) of the aldehyde (A) in the diol-containing composition relative to the total mass of the diol-containing composition (100%) was calculated using the integral value a of the H proton peak, the integral value b of the 4H proton peak of the α-methylene group in 1,6-hexanediol present at δ 3.69 to 3.50 ppm, and the following formula.

[0115]

number

[0116] In the above formula, "M(aldehyde (A))" represents the molecular weight of aldehyde (A) (6-hydroxyhexanal) (=116), and "M(16HD)" represents the molecular weight of 1,6-hexanediol (=118).

[0117] <Aldehyde (A) content in polycarbonate diol> The content of aldehyde (A) in the polycarbonate diol obtained in the Examples and Comparative Examples was measured according to the following procedure. In this evaluation, the definitions of "aldehyde (A)" and "content of aldehyde (A)" are as described in the above description of aldehyde (A). The polycarbonate diol was dissolved in CDCl3, and a nuclear magnetic resonance spectrometer (400 MHz, manufactured by JEOL Ltd., model name: ECZ-400) was used to measure the polycarbonate diol at a measurement temperature of 30° C. and an accumulation number of 64 times. 1 H-NMR measurement was performed. 1 From the H-NMR measurement results, two peaks observed at the following signal positions were identified, and integral values ​​A to C of each peak were obtained. The integral value of the 1H proton of the aldehyde group in the aldehyde (A) present at δ 9.80-9.75 ppm = A The integral value of the 2H proton peak of the methylene group next to the hydroxyl group terminal in the polycarbonate diol present at δ 3.69-3.50 ppm = B The integral value of the 4H proton peak of the γ methylene group of the structure derived from 1,6-hexanediol in polycarbonate diol present at δ 1.49-1.30 ppm = C

[0118] In addition, the integral value of the peak derived from the structural unit of the polycarbonate diol terminal derived from the aldehyde (A) was calculated as "ALD m " Similarly, the integral value of the peak derived from the structural unit of the polycarbonate diol terminal derived from 1,6-hexanediol (hereinafter abbreviated as "16HD") is referred to as "16HD mThe 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 " Based on the number of protons in the structural unit derived from aldehyde (A), the structural unit derived from DPC, and the structural unit derived from 16HD, the integral value of the peak derived from each of the structural units described above was calculated using the following formula. ALD m =A 16HD m =B÷2 16HD o =(C-16HD m ×4)÷4

[0119] Next, the number average molecular weight M(PCD) of the polycarbonate diol was calculated using the following formula.

[0120]

number

[0121] In the above formula, M(16HD o ) refers to the molecular weight (=116) of the structural unit derived from 16HD in the polycarbonate diol other than the polycarbonate diol terminal, and M (carbonyl group) refers to the molecular weight (=28) of the carbonyl group.

[0122] Next, the content ratio (unit: mass %) of the aldehyde (A) relative to 100% total mass of the polycarbonate diol (PCD) composition was calculated using the above value and the following formula.

[0123]

number

[0124] In the above formula, "M(aldehyde (A))" represents the molecular weight (=116) of aldehyde (A) (6-hydroxyhexanal).

[0125] <Color tone of polycarbonate diol> As an index of the color tone of the polycarbonate diol obtained in the examples and comparative examples, the APHA value was measured by comparing the polycarbonate diol sample with a standard solution placed in a colorimetric tube in accordance with JIS K0071-1 (1998). The reagent used was a chromaticity standard solution of 1000 degrees (1 mgPt / mL) (manufactured by Kishida Chemical Co., Ltd.).

[0126] <Number average molecular weight (Mn) calculated from the 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 acetylation reagent in accordance with JIS K1557-1. Then, the number average molecular weight (Mn) of the polycarbonate polyol was calculated from the obtained hydroxyl value using the following formula. Number average molecular weight (Mn) = (molecular weight of KOH) x 2000 / hydroxyl value

[0127] <Mass average molecular weight (Mw) and number average molecular weight (Mn) of polyurethane> For the polyurethanes obtained in the examples and comparative examples, the weight average molecular weight (Mw) and number average molecular weight (Mn) were determined by gel permeation chromatography (GPC measurement) according to the following procedure. The polyurethane sample was dissolved in dimethylacetamide (containing 0.3% by mass of anhydrous lithium bromide) so that the polyurethane concentration was 0.07% by mass, and this was used as a sample for GPC measurement. Using a GPC device (manufactured by Tosoh Corporation, model name: HLC-8420, column: Tosoh Corporation TSKgel SuperAWM-H x 2), GPC measurement was performed under the following measurement conditions: sample injection amount of about 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 in terms of number average molecular weight (Mn), weight average molecular weight (Mw), and molecular weight distribution (Mw / Mn) in terms of standard polystyrene using a commercially available monodisperse polystyrene solution as a standard sample.

[0128] <Polyurethane solution viscosity> The viscosity of the polyurethane solutions obtained in the examples and comparative examples was measured at 40° C. using an E-type viscometer (device name: TV-100EH, cone: 3°×R14, manufactured by Toki Sangyo Co., Ltd.).

[0129] <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. The polyurethane solutions obtained in the examples and comparative examples were applied to a 0.1 mm thick fluororesin sheet (product name: fluoro tape "Nitoflon 900", manufactured by Nitto Denko Corporation) using an applicator with a clearance of 500 μm, and then dried at a temperature of 80° C. for 1 hour, then at 100° C. for 0.5 hours, and further dried in a vacuum at 100° C. for 1.0 hour to dry and remove the solvent (DMF), and then left to stand at a constant temperature and humidity of 23° C. and 55% RH for 12 hours or more to obtain a laminated film in which a polyurethane layer was formed on the surface of the fluororesin sheet. The thickness of the polyurethane layer after drying was 100 μm. After peeling off the polyurethane layer from the obtained laminated film, a rectangular polyurethane film (length 150 mm, width 10 mm, thickness 100 μm) was cut out and used as a sample piece for a tensile test. (Tensile test) The above tensile test specimens were subjected to tensile tests 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 four tensile test specimens, and the 100% modulus, as well as the average value and standard deviation of the stress (breaking strength) and elongation (breaking elongation) at the time the specimen broke were measured. The following formulas were used to calculate the coefficient of variation of 100% modulus, breaking strength and breaking elongation. Coefficient of variation (%) = (standard deviation / average value) x 100

[0130] <Chemical resistance of polyurethane> As an index of the chemical resistance of the polyurethane, the mass change rate when the polyurethane was immersed in a test solution was measured using the method described below. The polyurethane solutions obtained in the Examples and Comparative Examples were applied to a 0.1 mm thick fluororesin sheet (product name: fluorotape "Nitoflon 900", manufactured by Nitto Denko Corporation) using an applicator with a clearance of 500 μm, and then dried at 80° C. for 1 hour, then at 100° C. for 0.5 hour, and further at 100° C. in a vacuum for 1.0 hour to dry and remove the solvent (DMF), thereby obtaining a laminated film in which a polyurethane layer was formed on the surface of the fluororesin sheet. The thickness of the polyurethane layer after drying was 100 μm. After peeling off the polyurethane layer from the obtained laminated film, a square polyurethane film (3 cm long, 3 cm wide, 100 μm thick) was cut out and used as a sample piece for chemical resistance testing. (Ethanol resistance test) The weight of the above-mentioned chemical resistance test specimen was measured using a precision balance, and then it 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 test specimen was removed and lightly wiped on both sides with a paper wiper, and then the mass was measured using a precision balance, and the mass change rate (increase rate) was calculated from the change in mass of the test specimen before and after the test. The closer the mass change rate is to 0%, the better the ethanol resistance.

[0131] [Raw materials used] The abbreviations for the raw materials used in the examples and comparative examples are as follows. 16HD: 1,6-Hexanediol (BASF Ltd.) 14BG: 1,4-butanediol (manufactured by Mitsubishi Chemical Corporation) DPC: Diphenyl carbonate (manufactured by Mitsubishi Chemical Corporation) Mg catalyst: Magnesium acetate tetrahydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) MDI: Diphenylmethane diisocyanate (Tokyo Chemical Industry Co., Ltd.) U-830: Dioctyltin monodecanoate (product name: Neostan U-830, manufactured by Nitto Kasei Co., Ltd.) DMF: N,N-Dimethylformamide dehydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0132] [Production and Evaluation of Polycarbonate Diol] <Comparative example I-1> In a 5L glass separable flask equipped with a stirrer, a distillate trap, and a pressure regulator, 16HD (diol (1)) as a diol-containing composition, DPC as a carbonate compound, and an aqueous Mg catalyst solution (concentration: 8.4 g / L-magnesium acetate tetrahydrate) as a transesterification catalyst were added in the amounts shown in Table 1, and the flask was replaced with a nitrogen atmosphere. The contents in the flask were stirred and heated to 160°C, 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 gradually reduced from 101 kPa to 24 kPa over 2 minutes, and the reaction was allowed to proceed for 90 minutes while removing the generated phenol 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 30 minutes. After continuing the reaction, the temperature of the contents was raised to 170°C, and the reaction was continued for another 120 minutes while removing phenol and unreacted diol (1) from the reaction system. The temperature of the contents was then allowed to cool to room temperature, and 660 g of polycarbonate diol was obtained. The obtained polycarbonate diol was designated "PCD1". The evaluation results of this PCD1 are shown in Table 1.

[0133] <Example I-1> In Comparative Example I-1, 36 g of 16HD was heated at 130°C for 3 hours while bubbling air, and the 16HD was partially oxidized and converted to 6-hydroxyhexanal. The reaction was carried out under the same conditions as in Comparative Example I-1, except that the 16HD was used as the raw material for structural unit (1). The obtained polycarbonate diol was named "PCD2". The evaluation results of this PCD2 are shown in Table 1.

[0134] <Example I-2> In Comparative Example I-1, 99 g of 16HD was heated at 130°C for 3 hours while bubbling air, and the 16HD was partially oxidized and converted to 6-hydroxyhexanal. The reaction was carried out under the same conditions as in Comparative Example I-1, except that the 16HD was used as the raw material for structural unit (1). The obtained polycarbonate diol was named "PCD3". The evaluation results of this PCD3 are shown in Table 1.

[0135] <Example I-3> In Comparative Example I-1, 313 g of 16HD was heated at 130°C for 3 hours while bubbling air, and the 16HD was partially oxidized and converted to 6-hydroxyhexanal. The reaction was carried out under the same conditions as in Comparative Example I-1, except that 16HD containing the oxidized 16HD was used as the raw material for structural unit (1). The obtained polycarbonate diol was named "PCD4". The evaluation results of this PCD4 are shown in Table 1.

[0136] In Examples I-1 to I-3, the content ratio of 6-hydroxyhexanal (aldehyde (A)) contained in the raw material 16HD used in the production of polycarbonate diol was changed by changing the amount of 16HD bubbled with air. In Examples I-1 to I-3, the aldehyde (A) contained in the obtained PCD2 to 4 includes free 6-hydroxyhexanal or 6-hydroxyhexanal bonded to polycarbonate diol. In Comparative Example I-1, no compound corresponding to the aldehyde (A) was detected in the obtained PCD1.

[0137] [Table 1]

[0138] [Production and evaluation of polyurethane] <Purification of polycarbonate diol> In order to remove phenol contained in the polycarbonate diols (PCD1 to PCD4) obtained in Examples I-1 to I-3 and Comparative Example I-1, 0.89 g of a 0.85 mass% phosphoric acid aqueous solution was added to 660 g of the polycarbonate diol to deactivate magnesium acetate. The solution was then sent to a thin-film distillation apparatus at a flow rate of 20 g / min, and thin-film distillation (temperature: 180 to 190°C, pressure: 40 to 67 Pa) was performed. The thin-film distillation apparatus had a diameter of 50 mm, a height of 200 mm, and an area of ​​0.0314 m. 2 The molecular distillation apparatus was a special MS-300 model with an internal condenser and a jacket manufactured by Shibata Scientific Co., Ltd. Hereinafter, PCD1 to PCD4 after thin-film distillation will be referred to as PCD1A, PCD2A, PCD3A, and PCD4A, respectively. The content ratios of aldehyde (A) in PCD1A to PCD4A obtained by thin-film distillation are shown in Table 2. The aldehyde (A) contained in PCD2A to PCD4A obtained after thin-film distillation of PCD2 to PCD4 includes free 6-hydroxyhexanal and 6-hydroxyhexanal bound to polycarbonate diol. No compound corresponding to aldehyde (A) was detected in PCD1A obtained after thin-film distillation of PCD1.

[0139] <Comparative Example II-1> A separable flask equipped with a thermocouple and a cooling tube was charged with 69.8 g of PCD1A preheated to 80°C, 6.30 g of 14BG as a chain extender, 0.02 g of U-830 as a catalyst, and 239 g of DMF as a reaction solvent, and immersed in an oil bath set to 55°C. The flask was stirred at a stirring speed of 60 rpm until the mixture was homogenous. The amount of water in the reaction solution in the flask was measured, and the amount of MDI consumed by the water was calculated. The amount of MDI sampled and extracted was also recorded, and the amount of each raw material was corrected. To the reaction solution, MDI equivalent to an NCO / OH molar ratio of 0.900 (including moisture correction) was added in a solid state using a funnel as an isocyanate compound, and the mixture was stirred at a stirring speed of 60 rpm until it became uniform. 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 14BG when MDI is added. Immediately after the addition of MDI, an exothermic peak accompanied by a rise in the reaction solution temperature of +10 to 15°C was observed, and 5 minutes after the exothermic peak subsided, the temperature of the oil bath was set to 70°C and increased. 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 (MW = 170,000 to 180,000) was reached. If the target was not reached, 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. The addition of MDI and the measurement of the molecular weight were repeated until the target Mw was reached. Finally, a polyurethane solution containing polyurethane with a total NCO / OH molar ratio of 0.990 and Mw = 170,032 was obtained. The evaluation results of the polyurethane solution and the resulting polyurethane are shown in Table 2.

[0140] <Examples II-1 to II-3> In Comparative Example II-1, except that PCD2A, PCD3A or PCD4A was used instead of PCD1A and the amount of each raw material was changed to the amount shown in Table 2, polyurethane polymerization was carried out under the same conditions and in the same manner as in Comparative Example II-1 to obtain a polyurethane solution. The evaluation results of the polyurethane solution and the resulting polyurethane are shown in Table 2.

[0141] [Table 2]

[0142] The following can be seen from Table 2: In Examples II-1 to II-3, the polyurethane polymerization stability was good. The obtained polyurethanes had good mechanical properties and chemical resistance, and the variation in mechanical properties was also suppressed. In particular, the polyurethane obtained in Example II-1 had better mechanical properties and chemical resistance than the polyurethanes obtained in Comparative Example II-1 and Example II-3, although the weight average molecular weight (Mw) was similar, and the balance between the two was excellent. On the other hand, in Comparative Example II-1, the diol-containing composition used for producing the polycarbonate diol did not contain the aldehyde (A), so the coefficient of variation of the mechanical strength of the obtained polyurethane was high, the quality of the polyurethane was non-uniform, and the breaking strength was insufficient.

Claims

1. A diol-containing composition used in a process for producing a polycarbonate diol, comprising an aldehyde and a diol (1) represented by the following general formula (1): HO-(CH ２ , ｎ t0.75 t0.75 (In the above general formula (1), n ​​is an integer from 3 to 6.)

2. The diol-containing composition according to claim 1 , wherein the diol-containing composition contains the aldehyde in an amount of 1 ppm by mass or more based on the total mass of the diol-containing composition.

3. The diol-containing composition according to claim 1 , wherein the diol-containing composition contains the aldehyde in an amount of 900 ppm by mass or less based on the total mass of the diol-containing composition.

4. The diol-containing composition according to claim 1, wherein the content of the diol (1) is 85% by mass or more relative to 100% by total mass of the diol-containing composition.

5. The diol-containing composition according to claim 1, wherein the diol (1) is at least one selected from 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol.

6. The diol-containing composition according to claim 1 , wherein the aldehyde is a compound having 4 to 6 carbon atoms and one or more aldehyde groups in the molecule.

7. The diol-containing composition according to claim 1 , wherein the diol (1) comprises a biomass-derived diol.

8. The diol-containing composition according to claim 1, wherein the diol (1) is 1,6-hexanediol, and the aldehyde is at least one selected from the group consisting of 6-hydroxyhexanal and adipaldehyde.

9. A polycarbonate diol obtained by using the diol-containing composition according to any one of claims 1 to 8 and a carbonate compound as raw materials.

10. A polyurethane made from the polycarbonate diol according to claim 9 and an isocyanate compound.

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