JP7632133B2 - Method for producing polyoxyalkylene diol, method for producing polyurethane resin precursor, method for producing polyurethane resin, polyurethane resin, polyurethane resin composition, and article - Google Patents

Description

The present invention relates to a method for producing a polyoxyalkylene diol, a method for producing a polyurethane resin precursor, a method for producing a polyurethane resin, a polyurethane resin, a polyurethane resin composition, and an article.

In general, polyurethane products such as adhesives, pressure sensitive adhesives, paints, coating agents, synthetic leathers, artificial leathers, elastomers, elastic fibers, flooring materials, and printing ink binders are required to have desired properties such as hydrophilicity, hydrophobicity, heat resistance, weather resistance, and mechanical properties.
As a method for controlling these properties, it has been proposed to prepare a polyurethane resin using a polyol obtained by ring-opening addition polymerization of an alkylene oxide such as propylene oxide using a polycarbonate diol as an initiator (see, for example, Patent Documents 1 and 2).

International Publication No. 2006/043569 JP 2005-179567 A

However, the polyol obtained by ring-opening addition polymerization of an alkylene oxide using a polycarbonate diol as an initiator sometimes undergoes phase separation. Such phase separation of the polyol may cause variations or deterioration in the physical properties of the polyurethane resin obtained using the polyol.

In view of the above problems, the present invention aims to provide a method for producing a polyoxyalkylene diol that can suppress phase separation of the polyoxyalkylene diol obtained by reacting a polycarbonate diol with a cyclic ether, a method for producing a polyurethane resin precursor using the polyoxyalkylene diol obtained by the method, a method for producing a polyurethane resin using the polyurethane resin precursor obtained by the method, a polyurethane resin obtained by the method, a polyurethane resin composition containing the polyurethane resin, and an article containing the polyurethane resin composition.

As a result of intensive research into solving the above problems, the present inventors have found that the above problems can be solved when a polycarbonate diol used as an initiator is at least one of a condensation polymer of two or more types of alcohols and a carbonate compound, and a reaction product of one or more types of alcohols and one or more types of cyclic esters with a carbonate compound, and satisfies either of the following (i) or (ii), and have completed the present invention.
(i) The content of carbonate groups in the polycarbonate diol is less than 30 mass%.
(ii) The content of carbonate groups in the polycarbonate diol is 30% by mass or more, and the content of carbonate groups in the polyoxyalkylene diol is 11% by mass or less.
That is, the present invention is as follows.
[1] A method for producing a polyoxyalkylene diol by reacting a polycarbonate diol with a cyclic ether in the presence of a ring-opening polymerization catalyst, the polycarbonate diol being at least one of a condensation polymer of two or more alcohols with a carbonate compound, and a reaction product of one or more alcohols and one or more cyclic esters with a carbonate compound, and satisfying either of the following (i) and (ii):
(i) The content of carbonate groups in the polycarbonate diol is less than 30 mass%.
(ii) The content of carbonate groups in the polycarbonate diol is 30% by mass or more, and the content of carbonate groups in the polyoxyalkylene diol is 11% by mass or less.
[2] The method for producing a polyoxyalkylene diol according to the above [1], wherein the content of a carbonate group in the polycarbonate diol is less than 30% by mass, and the content of a carbonate group in the polyoxyalkylene diol is 15% by mass or less.
[3] The method for producing a polyoxyalkylene diol according to the above [1], wherein the content of a carbonate group in the polycarbonate diol is 30% by mass or more, and the content of a carbonate group in the polyoxyalkylene diol is 10% by mass or less.
[4] The method for producing a polyoxyalkylene diol according to the above [3], wherein the content of carbonate groups in the polyoxyalkylene diol is 9% by mass or less.
[5] The method for producing a polyoxyalkylene diol according to any one of the above [1] to [4], wherein the number average molecular weight of the polycarbonate diol is 400 or more and 4,000 or less.
[6] The method for producing a polyoxyalkylene diol according to any one of [1] to [5] above, wherein the number average molecular weight of the polyoxyalkylene diol is 450 or more and 40,000 or less.
[7] A method for producing a polyurethane resin precursor, comprising obtaining a polyoxyalkylene diol by the method for producing a polyoxyalkylene diol according to any one of [1] to [6] above, and reacting the obtained polyoxyalkylene diol with a polyisocyanate compound.
[8] The method for producing a polyurethane resin precursor according to the above [7], wherein the molecular weight of the polyisocyanate compound is 120 or more and 400 or less.
[9] The method for producing a polyurethane resin precursor according to [7] or [8], wherein the polyisocyanate compound is a diisocyanate compound.
[10] A method for producing a polyurethane resin, comprising obtaining a polyurethane resin precursor by the method for producing a polyurethane resin precursor according to any one of [7] to [9] above, and producing a polyurethane resin using the obtained polyurethane resin precursor.
[11] A method for producing a polyurethane resin, comprising reacting the polyurethane resin precursor with a chain extender to produce a polyurethane resin, wherein the chain extender is at least one selected from the group consisting of a polyol having at least two active hydrogens that react with an isocyanate group and a polyamine having at least two active hydrogens that react with an isocyanate group, according to the method for producing a polyurethane resin described in [10] above.
[12] The method for producing a polyurethane resin according to the above [11], wherein the chain extender has a divalent hydrocarbon group having 2 to 12 carbon atoms, or a divalent hydrocarbon group having 2 to 12 carbon atoms containing an etheric oxygen atom between carbon atoms.
[13] A polyurethane resin obtained by the method for producing a polyurethane resin according to any one of [10] to [12] above.
[14] The polyurethane resin according to [13] above, wherein the polyurethane resin has a number average molecular weight of more than 800.
[15] A polyurethane resin composition comprising the polyurethane resin according to [13] or [14] above.
[16] An article comprising the polyurethane resin composition according to [15] above.

According to the present invention, it is possible to provide a method for producing a polyoxyalkylene diol that can suppress phase separation of the polyoxyalkylene diol obtained by reacting a polycarbonate diol with a cyclic ether, a method for producing a polyurethane resin precursor using the polyoxyalkylene diol obtained by the method, a method for producing a polyurethane resin using the polyurethane resin precursor obtained by the method, a polyurethane resin obtained by the method, a polyurethane resin composition containing the polyurethane resin, and an article containing the polyurethane resin composition.

The present invention will be described in detail below.
In this specification, any of the items that are considered to be preferred may be adopted arbitrarily, and it can be said that a combination of preferred items is more preferable.
In addition, in this specification, the expression "XX to YY" means "XX or more and YY or less."
In addition, in this specification, the lower limit and upper limit described in stages for the preferred numerical ranges (e.g., ranges of content, etc.) can be independently combined. For example, the description "preferably 10 to 90, more preferably 30 to 60" can be combined with the "preferable lower limit (10)" and the "more preferable upper limit (60)" to form "10 to 60." In addition, in the numerical ranges described in this specification, the upper limit or lower limit of the numerical range may be replaced with a value shown in the examples.
In this specification, the term "unit" constituting a polymer means an atomic group formed by polymerization of a monomer.
In this specification, the number average molecular weight (hereinafter sometimes referred to as "Mn") and weight average molecular weight (hereinafter sometimes referred to as "Mw") of the polyoxyalkylene diol or polycarbonate diol are polypropylene glycol-equivalent molecular weights measured by gel permeation chromatography (GPC) according to the method described in the Examples, using a calibration curve prepared using polypropylene glycol with a known hydroxyl group-equivalent molecular weight.
In this specification, the Mn and Mw of a polyurethane resin or a polyurethane resin precursor are polystyrene-equivalent molecular weights measured by gel permeation chromatography (GPC) using the method described in the Examples and creating a calibration curve using standard polystyrene samples with known molecular weights.
In this specification, the molecular weight distribution is a value calculated from the above Mw and Mn, and is the ratio of Mw to Mn (hereinafter sometimes referred to as "Mw/Mn").
Furthermore, in this specification, the term "condensation polymer" means "a condensation polymer obtained by polycondensation through an ester exchange reaction", and the term "reactant" means "a reactant obtained by condensation polymerization through an ester exchange reaction and ring-opening polymerization of a cyclic ester".

(Method for producing polyoxyalkylene diol)
The method for producing a polyoxyalkylene diol of the present invention is a method for producing a polyoxyalkylene diol (hereinafter, sometimes referred to as "(PCD)") obtained by reacting a polycarbonate diol (hereinafter, sometimes referred to as "(PCD) initiator") with a cyclic ether in the presence of a ring-opening polymerization catalyst, in which the polycarbonate diol is at least one of a condensation polymer of two or more types of alcohols and a carbonate compound, and a reaction product of one or more types of alcohols and one or more types of cyclic esters with a carbonate compound, and the method for producing a polyoxyalkylene diol satisfies either of the following (i) and (ii):
(i) The content of carbonate groups in the polycarbonate diol is less than 30 mass%.
When the content of carbonate groups in the polycarbonate diol is less than 30% by mass, the content of carbonate groups in the polyoxyalkylene diol is not particularly limited, but is preferably 15% by mass or less, more preferably 13.5% by mass or less, particularly preferably 10% by mass or less, and is preferably 1% by mass or more, more preferably 2% by mass or more, particularly preferably 3% by mass or more.
(ii) The content of carbonate groups in the polycarbonate diol is 30% by mass or more, and the content of carbonate groups in the polyoxyalkylene diol is 11% by mass or less.
When the content of carbonate groups in the polycarbonate diol is 30% by mass or more, the content of carbonate groups in the polyoxyalkylene diol is not particularly limited as long as it is 11% by mass or less, but is preferably 10% by mass or less, more preferably 9% by mass or less, even more preferably 5% by mass or less, particularly preferably 4% by mass or less, and also preferably 1% by mass or more, more preferably 2% by mass or more, particularly preferably 3% by mass or more.
Here, the "carbonate group content" is usually a value calculated based on the "method of calculating the carbonate group content" described in the Examples. However, when the "carbonate group content in the polycarbonate diol" and the "carbonate group content in the polyoxyalkylene diol" cannot be calculated by the "method of calculating the carbonate group content" described in the Examples (for example, when the polycarbonate diol can be analyzed to be at least one of a condensation polymer of two or more alcohols and a carbonate compound, and a reaction product of one or more alcohols and one or more cyclic esters and a carbonate compound, but the structure of the alcohol, cyclic ester, or polycarbonate diol cannot be specifically identified, and the "number of carbonate groups in one molecule of the polycarbonate diol" cannot be calculated), a sample (polycarbonate diol or polyoxyalkylene diol) is dissolved in deuterated chloroform to which an internal standard substance has been added, and ¹ From the NMR chart obtained by measuring H-NMR, the ratio of the total area of the peak based on the proton bonded to the carbon atom adjacent to the carbonate group to the total area of the peak based on the proton of the internal standard is calculated, the number of carbonate groups per unit weight is calculated, and further, the "content of carbonate groups in the polycarbonate diol" or the "content of carbonate groups in the polyoxyalkylene diol" is calculated using the Mn of the polycarbonate diol or polyoxyalkylene diol determined by GPC.
By satisfying either the above (i) or (ii), phase separation of the polyoxyalkylene diol obtained by reacting a polycarbonate diol with a cyclic ether can be suppressed.
Incidentally, the reason why the present invention can solve the problem is unclear, but it is believed that the present invention can solve the problem by making the content of carbonate groups in the polycarbonate diol less than 30% by mass (i.e., making the polarity of the polycarbonate diol small), or by making the content of carbonate groups in the polyoxyalkylene diol after the addition of the cyclic ether 11% by mass or less even if the content of carbonate groups in the polycarbonate diol is 30% by mass or more (i.e., increasing the amount of cyclic ether added to the polycarbonate diol to relatively reduce the content of carbonate groups in the polyoxyalkylene diol after the addition of the cyclic ether, or by reducing the remaining amount of polycarbonate diol to which the cyclic ether is not added).
This is presumably due to the suppression of phase separation occurring between the two components, "polycarbonate diol having a cyclic ether added thereto" and "polycarbonate diol having no cyclic ether added thereto."
In the above (i) and (ii), if the content of carbonate groups is within the preferred range, phase separation of the polyoxyalkylene diol obtained by reacting the polycarbonate diol with the cyclic ether can be more reliably suppressed.

<Polycarbonate diol>
The polycarbonate diol is not particularly limited so long as it is at least one of a condensation polymer of two or more kinds of alcohols and a carbonate compound, and a reaction product of one or more kinds of alcohols and one or more kinds of cyclic esters with a carbonate compound.

The Mn of the polycarbonate diol is not particularly limited, but is preferably 400 to 4,000, more preferably 450 to 3,500, and particularly preferably 500 to 3,000.
When the Mn of the polycarbonate diol is not less than the above lower limit, the tensile properties and mechanical strength of a polyurethane resin obtained by using the polyoxyalkylene diol derived from the polycarbonate diol in a film are better. When the Mn is not more than the above upper limit, the transparency (haze) of a polyurethane resin obtained by using the polyoxyalkylene diol derived from the polycarbonate diol in a film is better.

The Mw/Mn of the polycarbonate diol is not particularly limited, but is preferably 3.5 or less, more preferably 3.0 or less, and particularly preferably 2.5 or less.
When the Mw/Mn of the polycarbonate diol is equal to or less than the upper limit, the viscosity of the polycarbonate diol can be reduced, making it easy to handle.

The method for producing polycarbonate diol is not particularly limited, and examples thereof include the methods described in JP-A-2012-77280, JP-A-2014-080590, JP-A-2015-91937, JP-A-2001-270938, JP-A-2010-126591, JP-A-02-289616, and JP-A-04-239023.

When the polycarbonate diol is a condensation polymerization product of two types of alcohol and a carbonate compound, the molar ratio of the amount of one of the two types of alcohol to the amount of the other of the two types of alcohol is not particularly limited, but from the viewpoint of the tensile properties and mechanical strength when the polyurethane resin obtained using the polycarbonate diol derived from the alcohol is made into a film, it is preferably 10/90 to 90/10, more preferably 15/85 to 85/15, even more preferably 20/80 to 80/20, even more preferably 30/70 to 70/30, even more preferably 40/60 to 60/40, and particularly preferably 45/55 to 55/45. However, when the polycarbonate diol is a condensation polymer of two types of alcohol and a carbonate compound, and the two types of alcohol are 1,9-nonanediol (1,9-ND) and 2-methyl-1,8-octanediol (MOD), the molar ratio of the amount of one of the two types of alcohol to the amount of the other of the two types of alcohol is not particularly limited, but is preferably 10/90 to 90/10, more preferably 15/85 to 85/15, from the viewpoint of the tensile properties and mechanical strength when the polyurethane resin obtained using the polycarbonate diol derived from the alcohol is made into a film.

When the polycarbonate diol is a reaction product of one type of alcohol and one type of cyclic ester with a carbonate compound, the molar ratio of the amount of the one type of alcohol to the amount of the one type of cyclic ester is not particularly limited, but from the viewpoint of the tensile properties and mechanical strength when the polyurethane resin obtained using the polyoxyalkylene diol derived from the alcohol and the cyclic ester is made into a film, it is preferably 10/90 to 90/10, more preferably 15/85 to 85/15, even more preferably 20/80 to 80/20, even more preferably 30/70 to 70/30, even more preferably 40/60 to 60/40, and particularly preferably 45/55 to 55/45.

<<Alcohol>>
Examples of the alcohol include diols. Specific examples of the diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol (hereinafter sometimes referred to as "1,4-BD"), 1,5-pentanediol (hereinafter sometimes referred to as "1,5-PD"), 1,6-hexanediol (hereinafter sometimes referred to as "1,6-HD"), 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol (hereinafter sometimes referred to as "1,9-ND"), 1,10-decanediol, 1,11-undecanediol, 1,1 Diols having no side chains, such as 2-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, and 1,20-eicosanediol; 2-methyl-1,8-octanediol (hereinafter sometimes referred to as "MOD"), 2,2-dimethyl-1,3-propanediol (neopentyl glycol, hereinafter sometimes referred to as "NPG"), 2-ethyl-1,3-hexanediol, and 2-ethyl-1,6-hexanediol, Diols having a side chain such as 2-methyl-1,4-butanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,4-dimethyl-1,5-pentanediol, and 2,4-diethyl-1,5-pentanediol; 1,3-cyclohexanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, isosorbide (hereinafter sometimes referred to as "iSB"), 2-bis(4-hydroxycyclohexyl)-propanediol, and the like; cyclic diols such as propane, 2,7-norbornanediol, 2,3-norbornanediol, tetrahydrofuran-2,2-dimethanol, 2,5-bis(hydroxymethyl)-1,4-dioxane, and 5,5-bis(hydroxymethyl)-2-phenyl-1,3-dioxane; and diols having an aromatic ring such as p-xylene glycol, p-tetrachloroxylenediol, 1,4-bis(hydroxyethoxy)benzene, and 2,2-bis[(4-hydroxyethoxy)phenyl]propane. These may be used alone or in combination of two or more.

Among these, from the viewpoint of reactivity with carbonate compounds, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 2-methyl-1,8-octanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), chol), 2-ethyl-1,6-hexanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,3-cyclohexanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2-bis(4-hydroxycyclohexyl)-propane 2,7-norbornanediol, tetrahydrofuran-2 ,2-dimethanol, 2,5-bis(hydroxymethyl)-1,4-dioxane, and isosorbide are preferred, and ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, 2-ethyl-1,6-hexanediol, 1,4-cyclohexanedimethanol, 2-methyl-1,8-octanediol, isosorbide, 2-methyl-1,3-propanediol, 2,2-dimethyl- ethyl-1,3-propanediol (neopentyl glycol), and 3-methyl-1,5-pentanediol are more preferred, and 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, 2-methyl-1,8-octanediol, isosorbide, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), and 3-methyl-1,5-pentanediol are particularly preferred.

<<Cyclic Esters>>
The cyclic ester is not particularly limited, and examples thereof include ε-caprolactone (hereinafter sometimes referred to as "CL"), β-propiolactone, β-methyl-β-propiolactone, δ-valerolactone, glycolide, lactide, etc. These may be used alone or in combination of two or more.
Of these, ε-caprolactone is preferred.

<<Carbonate compounds>>
The carbonate compound used in the production of polycarbonate diol is not particularly limited, and examples thereof include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, diphenyl carbonate, ethylene carbonate, trimethylene carbonate, propylene carbonate, 1,2-butylene carbonate, neopentylene carbonate, etc. These may be used alone or in combination of two or more.
Among these, dimethyl carbonate, diethyl carbonate, diphenyl carbonate, and ethylene carbonate are preferred from the viewpoint of ease of reaction with alcohols and cyclic esters.
Here, dimethyl carbonate and diethyl carbonate are preferred from the viewpoint that the boiling point of the compound eliminated during the reaction is low and therefore the equilibrium reaction is likely to lean towards the target compound, and diphenyl carbonate is preferred from the viewpoint that the difference in boiling point between the compound eliminated during the reaction and the target compound is large and therefore the target compound can be easily separated.

The amount of carbonate compound used in the production of polycarbonate diol is not particularly limited, but from the viewpoint of the tensile properties and mechanical strength when the polyurethane resin obtained using the polycarbonate diol derived from the carbonate compound is made into a film, the amount is preferably 40 to 160 parts by mass, more preferably 50 to 150 parts by mass, and particularly preferably 60 to 140 parts by mass per 100 parts by mass of the total amount of two or more alcohols (or 100 parts by mass of the total amount of one or more alcohols and one or more cyclic esters).

The structure of the polycarbonate diol, which is a condensation polymer of two or more kinds of alcohols and a carbonate compound, is not particularly limited, and examples thereof include a structure represented by the following formula A.
HO-(R ³ -OC(=O)-O) _u -R ³⁰ -OH...Formula A

^R3 in formula A is a carbon chain derived from an alcohol ( ^R3 in formula G described later). The carbon chain derived from an alcohol is a residue obtained by removing a hydroxyl group from an alcohol, and may be either a linear or branched chain.
Examples of ^R3 in formula A include chain hydrocarbon groups having 2 to 20 carbon atoms and cyclic hydrocarbon groups having a ring structure having 6 to 20 carbon atoms. These groups may have one or more substituents.

The number of carbon atoms in the chain hydrocarbon group of ^R3 is not particularly limited as long as it is 2 to 20, but is preferably 2 to 18, and more preferably 3 to 16. In addition, the chain hydrocarbon group of ^R3 is preferably a linear or branched alkylene group, and is preferably unsubstituted.

When ^R3 is a chain hydrocarbon group having a substituent, the substituent is not particularly limited, and examples thereof include an alkyl group having 1 to 8 carbon atoms; a halogen atom such as a chlorine atom; and an alkoxy group such as a methoxy group or an ethoxy group.
The alkyl group having 1 to 8 carbon atoms is not particularly limited, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, etc. Among these, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and a t-butyl group are preferable, and a methyl group, an ethyl group, and a t-butyl group are more preferable.
When ^R3 is a chain hydrocarbon group having a substituent, the number of the substituents is not particularly limited, but is preferably 1 to 4, and more preferably 1 to 2.

When R ³ in formula A is a cyclic hydrocarbon group having a ring structure containing 6 to 20 carbon atoms, the atoms constituting the ring may contain an oxygen atom, but when an oxygen atom is contained, adjacent atoms are not both oxygen atoms.

When ^R3 is a cyclic hydrocarbon group having a substituent, the substituent is not particularly limited, and examples thereof include an alkyl group having 1 to 8 carbon atoms; a halogen atom such as a chlorine atom; and an alkoxy group such as a methoxy group or an ethoxy group.
The alkyl group having 1 to 8 carbon atoms is not particularly limited, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, etc. Among these, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and a t-butyl group are preferable, and a methyl group, an ethyl group, and a t-butyl group are more preferable.
When ^R3 is a cyclic hydrocarbon group having a substituent, the number of the substituents is not particularly limited, but is preferably 1 to 4, and more preferably 1 to 2.

(R ³ -O-C(═O)-O) _u in formula A includes units represented by two or more types of (R ³ -O-C(═O)-O) in which R ³ is different, and may include units represented by three or more types of (R ³ -O-C(═O)-O).
When the polycarbonate diol contains two or more types of units represented by (R ³ -O-C(═O)-O), the low-temperature properties and transparency (haze) of the polyurethane resin obtained using the polycarbonate diol as an initiator can be improved while making use of ^the strength properties of the polyurethane resin.
It is presumed that the inclusion of a unit represented by the formula (I) causes the crystallinity to be appropriately disrupted.
The arrangement of the two or more types of units represented by (R ³ -O-C(=O)-O) constituting the polycarbonate diol may be random, may be block, or may be a combination of both random and block.

The number u in formula A is not particularly limited as long as it is an integer of 1 or more, and is appropriately adjusted according to the molecular weight of the (R ³ -O-C(═O)-O) group so that the Mn of the polycarbonate diol falls within the desired range, and is preferably 2 to 50, more preferably 3 to 30.

It is preferable that "(R ³ -O-C(═O)-O) _u " in formula A is composed of a combination of two or more types of units selected from the group consisting of units B represented by the following formula B and units C represented by the following formula C. Here, the two or more types of units may be selected from either units B or units C, or may be selected from both units B and units C.
(R ³¹ -OC(=O)-O)...Formula B
(R ³² -O-C(=O)-O)...Formula C

R ³¹ in formula B is a linear alkylene group having an even number of carbon atoms among R ³ , specifically, one or more linear alkylene groups selected from those having 2, 4, 6, 8, 10, 12, 14, 16, 18 and 20 carbon atoms.

R ³² in formula C is a group among R ³ other than R ^31. Specific examples of R ³² are not particularly limited, and include, for example, a chain hydrocarbon group having 3 to 20 carbon atoms (excluding linear alkylene groups having an even number of carbon atoms) and a cyclic hydrocarbon group having a ring structure having 6 to 20 carbon atoms, and these groups may have one or more substituents.
When R ³² is a cyclic hydrocarbon group having a ring structure with 6 to 20 carbon atoms, the atoms constituting the ring may contain an oxygen atom, but when an oxygen atom is contained, adjacent atoms are not both oxygen atoms.

Specific examples of R ³² in formula C include, for example, —CH ₂ —C(C ₂ H ₅ )H—, —CH ₂ —CH(CH ₃ )—CH ₂ —, —CH 2 —CH 2 —CH ₂ —CH ₂ —CH ₂ —CH ₂ —CH ₂ —, —CH ₂ —CH ₂ —C(CH ₃ )—CH 2 —CH 2 —, —CH ₂ —CH 2 —CH 2 —CH ₂ —CH ₂ —CH 2 —CH ₂ —CH ₂ —CH ₂ —CH ₂ —CH _{2 —} , —CH ₂ —CH(CH 3 )—CH ₂ —CH ₂ —CH 2 —CH 2 —CH ₂ —CH ₂ —CH 2 —, —CH 2 —CH ₂ —CH ₂ —CH ₂ —CH 2 —CH 2 —CH ₂ —CH ( _{CH 3} )—CH ₂ —CH _{2 —CH 2} —CH ₂ —CH ₂ —CH ₂ —CH _{2 —} -, -CH ₂ -C(CH ₃ ) ₂ -CH ₂ -, a group represented by the following formula D, a group represented by the following formula E, -CH ₂ -CH(CH ₃ )-CH ₂ -CH(CH ₃ )-CH ₂ -CH 2 -, -CH ₂ -CH ₂ -CH(CH ₃ )-CH ₂ -CH ₂ -, -CH ₂ -CH(C ₂ H ₅ )-CH ₂ -CH(C ₂ H ₅ )-CH ₂ -, etc. These may be used alone or in combination of two or more.

The combination of two or more types of units selected from both the unit B and the unit C is not particularly limited, but for example, the following (a) to (c) are preferred.
(a) a combination of ((CH ₂ ) ₆ -O-C(=O)-O) as unit B and ((CH ₂ ) ₅ -O-C(=O)-O) as unit C; (b) a combination of ((CH ₂ ) ₄ -O-C(=O)-O) as unit B and (R ³² -O-C(=O)-O) as unit C (wherein R ³² is formula D above); (c) a combination of ((CH ₂ ) ₄ -O-C(=O)-O) as unit B and (-CH ₂ -C(CH ₃ ) ₂ -CH ₂ -O-C(=O)-O) as unit C. There are no particular limitations on the combination of two or more types of units selected from unit B. For example, a combination of ((CH ₂ ) ₆ -O-C(=O)-O) as unit B and ((CH ₂ ) ₄ -OC(=O)-O) combination is preferred.
The combination of two or more types of units selected from the unit C is not particularly limited, but for example, the following (a) or (b) is preferable.
(a) a combination of ((CH ₂ ) ₉ -O-C(═O)-O) as unit C and (CH ₂ -CH(CH ₃ )-CH ₂ -CH ₂ -CH ₂ -CH ₂ -CH 2 -CH _{2 -O} -C(═O)-O) as unit C;
(b) A combination of ((CH ₂ ) ₉ -O-C(═O)-O) as unit C and (CH ₂ -CH ₂ -CH ₂ -CH ₂ -CH ₂ -CH ₂ -CH(CH ₃ )-CH ₂ -O-C(═O)-O) as unit C.

When the unit B is contained, the proportion of the unit B in (R ³ -O-C(═O)-O) _u in formula A is not particularly limited, but is preferably 5 to 95 mol %, more preferably 10 to 90 mol %, and particularly preferably 20 to 85 mol %.
When the proportion of the unit B is within the above preferred range, the crystallinity of the resulting polymer can be easily adjusted to an appropriate level.
When the unit C is contained, the proportion of the unit C in (R ³ -O-C(═O)-O) _u in formula A is not particularly limited, but is preferably 5 to 95 mol %, more preferably 10 to 90 mol %, and particularly preferably 15 to 80 mol %.
When the proportion of the units C is within the above preferred range, the crystallinity of the resulting polymer can be easily adjusted to an appropriate level.

The proportion of each unit in (R ³ —O—C(═O)—O) _u is determined by ¹ H-NMR.
Specifically, polycarbonate diol is dissolved in deuterated chloroform to a concentration of 10% by mass, and ¹ H-NMR is measured with a resolution of 400 MHz (product name: JNM-ECZ400SJNM, manufactured by JEOL Ltd.), and calculation is performed based on the peak due to hydrogen bonded to the carbon adjacent to the carbonate group.
For example, the molar ratio of units derived from 1,4-butanediol (1,4-BD) to units derived from neopentyl glycol (NPG) can be calculated by calculating the peak area at 4.10-4.20 ppm based on the two protons bonded to the methylene group of 1,4-BD adjacent to the carbonate group and the peak area at 3.90-4.00 ppm based on the two protons bonded to the methylene group of NPG adjacent to the carbonate group, and then calculating the ratio of these peak areas.

R ³⁰ and preferred embodiments thereof in formula A are the same as R ³ .

The structure of the polycarbonate diol which is a reaction product of one or more alcohols and one or more cyclic esters with a carbonate compound is not particularly limited, and examples thereof include a structure represented by the following formula A2.
HO-(R ³ -O-C(=O)-O) _u (R ³³ -C(=O)-O) _u2 -R ³⁴ -OH
...Formula A2

R ³ and preferred embodiments thereof in formula A2 are the same as R ³ in formula A.
Moreover, u and preferred embodiments thereof in formula A2 are the same as u in formula A.

In formula A2, R ³³ is a carbon chain derived from a cyclic ester. The carbon chain derived from a cyclic ester is a residue obtained by removing an ester group from a cyclic ester. However, when the cyclic ester has multiple ester groups, R ³³ is a carbon chain present between the multiple ester groups. For example, when the cyclic ester is glycolide, R ³³ is -(CH ₂ )-, and when the cyclic ester is lactide, R ³³ is -CH(-CH ₃ )-, -(CH ₂ ) ₃ -, etc.
Specific examples of R ³³ in formula A2 include chain hydrocarbon groups having 1 to 10 carbon atoms. The chain hydrocarbon group of R ³³ is preferably a linear or branched alkylene group. Specific examples of R ³³ include -(CH ₂ ) ₅ -, -(CH 2 ) 2 -, -C(CH ₃ )H-CH _{2 -} , -(CH ₂ ) ₄ -, -(CH ₂ ) -, -CH(-CH _{3 )} -, -(CH ₂ ) ₃ -, and the like.

Furthermore, u2 in formula A2 is not particularly limited as long as it is an integer of 1 or more, and is appropriately adjusted according to the molecular weight of the (R ³³ -C(=O)-O) group so that the Mn of the polycarbonate diol falls within the desired range, and is preferably 2 to 50, more preferably 3 to 30.

In formula A2, R ³⁴ is R ³ or R ³³ , and preferred embodiments thereof are also the same as those of R ³ and R ³³ .

In formula A2, (R ³ -O-C(═O)-O) _u is a "repeating unit derived from an alcohol (a repeating unit of "carbon chain derived from an alcohol + carbonate group")", (R ³³ -C(═O)-O) _u2 in formula A2 is a "repeating unit derived from a cyclic ester (a repeating unit of "carbon chain derived from a cyclic ester + ester group")", and R ³⁴ is a "carbon chain derived from an alcohol that does not constitute a repeating unit, or a carbon chain derived from a cyclic ester that does not constitute a repeating unit". The arrangement of the units represented by (R ³ -O-C(═O)-O) and (R ³³ -C(═O)-O) that constitute the polycarbonate diol may be random, may be block, or may be a combination of both random and block.
For example, the structure of polycarbonate diol, which is a reaction product of 1,6-hexanediol and ε-caprolactone, has a repeating unit derived from an alcohol, ((CH ₂ ) ₆ -O-C(=O)-O) _u , and a repeating unit derived from a cyclic ester, ((CH ₂ )
₅ -C(=O)-O) _u2 , an alkylene group having 6 carbon atoms (-(CH ₂ ) _6- ) as a carbon chain derived from an alcohol that is not a repeating unit, an alkylene group having 5 carbon atoms (-(CH ₂ ) _5- ) as a carbon chain derived from a cyclic ester that is not a repeating unit, and hydroxyl groups at both ends.
Preferable specific examples of (R ³³ —C(═O)—O) _u2 in formula A2 include groups represented by the following formula F (v in formula F is an integer of 1 or more).

The structure of the alcohol used in the production of the polycarbonate diol is not particularly limited, and examples thereof include the structure represented by the following formula G.
HO-R ³ -OH...Formula G

^R3 in formula G, which represents an example of the structure of an alcohol used in the production of a polycarbonate diol, is the same as ^R3 in formula A or formula A2, which represents an example of the structure of a polycarbonate diol, and preferable combinations of ^R3 are also the same as the preferable combinations of ^R3 .

The structure of the carbonate compound used in the production of the polycarbonate diol is not particularly limited, and examples thereof include a structure represented by the following formula H.
R ⁴ -O-C(=O)-O-R ⁵ ...Formula H

In formula H, which represents an example of the structure of a carbonate compound used in the production of a polycarbonate diol, ^R4 and ^R5 are each independently an alkyl group having 1 to 20 carbon atoms or a phenyl group. Here, ^R4 and ^R5 may be bonded to each other to form a ring.

<Cyclic Ether>
Examples of cyclic ethers include cyclic ethers having two carbon atoms forming a ring, such as ethylene oxide, propylene oxide (hereinafter sometimes referred to as "PO"), 1,2-butylene oxide, and 2,3-butylene oxide. These may be used alone or in combination of two or more. However, the above cyclic ethers do not include ethers (tetrahydrofuran, dioxane, etc.) described later.
Among these, propylene oxide is preferred from the viewpoint of tensile properties and mechanical strength when the polyurethane resin obtained by using the cyclic ether is formed into a film.

The reaction between a cyclic ether and a polycarbonate diol is a reaction in which, using the polycarbonate diol as an initiator, the cyclic ether undergoes ring-opening addition polymerization to the hydroxyl groups (active hydrogen-containing groups) of the polycarbonate diol in the presence of a ring-opening polymerization catalyst. This produces a polyoxyalkylene diol that has a polyoxyalkylene chain made of oxyalkylene units and terminates with a hydroxyl group.

When two or more types of cyclic ethers are reacted with a polycarbonate diol, the ring-opening addition polymerization may be random polymerization, block polymerization, or a combination of random polymerization and block polymerization.

The polymerization temperature for the ring-opening polymerization reaction of the cyclic ether is not particularly limited, but is preferably 30 to 180°C, more preferably 70 to 160°C, and particularly preferably 90 to 140°C.
When the polymerization temperature is equal to or higher than the above lower limit, the ring-opening polymerization of the cyclic ether can be reliably initiated, whereas when the polymerization temperature is equal to or lower than the above upper limit, a decrease in the polymerization activity of the ring-opening polymerization catalyst can be suppressed.

The polymerization time for the ring-opening polymerization reaction of the cyclic ether is not particularly limited, but is preferably 2 to 18 hours, more preferably 3 to 14 hours, and particularly preferably 4 to 10 hours.
When the polymerization time is equal to or more than the above lower limit, the reaction performance is excellent, and when it is equal to or less than the above upper limit, the economical efficiency is excellent.

The amount of the cyclic ether to be charged is not particularly limited, but is preferably 30 to 1500 parts by mass, more preferably 50 to 1200 parts by mass, and particularly preferably 100 to 900 parts by mass, based on 100 parts by mass of the polycarbonate diol (PCD).
When the amount of the cyclic ether charged is within the above preferred range, the tensile properties and mechanical strength of a film made from a polyurethane resin obtained by using the cyclic ether can be improved.

The ring-opening polymerization reaction of the cyclic ether is preferably carried out under good stirring conditions.
When using a general stirring method using a stirring blade, it is preferable to make the rotation speed of the stirring blade as fast as possible within a range in which a large amount of gas from the gas phase is not taken into the reaction liquid and the stirring efficiency is not reduced. From the viewpoint of narrowing the Mw/Mn of the obtained polymer, it is preferable to make the supply speed of the cyclic ether into the reaction vessel as slow as possible, but since this reduces the production efficiency, it is preferable to determine the supply speed of the cyclic ether by comparing and balancing these factors.

A reaction solvent may be used in the ring-opening polymerization reaction of the cyclic ether.
The reaction solvent is not particularly limited, and examples thereof include aliphatic hydrocarbons such as hexane, heptane, cyclohexane, etc., aromatic hydrocarbons such as benzene, toluene, xylene, etc., halogen-based solvents such as chloroform, dichloromethane, etc., ethers such as tetrahydrofuran, dioxane, etc. These may be used alone or in combination of two or more.
Among these, hexane and tetrahydrofuran are preferred from the viewpoints of their low boiling points and ease of removal after the completion of the reaction.
The amount of the reaction solvent used is not particularly limited, and a desired amount can be used.

<Ring-opening polymerization catalyst>
The ring-opening addition polymerization catalyst is not particularly limited, and examples thereof include composite metal cyanide complex catalysts (hereinafter sometimes referred to as "DMC catalysts"); alkali catalysts such as sodium hydroxide, potassium hydroxide, and cesium hydroxide; Ziegler-Natta catalysts consisting of an organoaluminum compound and a transition metal compound; metal porphyrin catalysts as complexes obtained by reacting porphyrin; phosphazene catalysts; imino group-containing phosphazenium salts; tris(pentafluorophenyl)borane; catalysts consisting of metal salen complexes; and catalysts consisting of reduced Robson's type macrocyclic ligands. These may be used alone or in combination of two or more.
When a DMC catalyst is used as a ring-opening addition polymerization catalyst, polyoxyalkylene diols having a narrow Mw/Mn and lower viscosity can be obtained.
The DMC catalyst is not particularly limited, and examples thereof include a zinc hexacyanocobaltate complex in which the ligand is t-butyl alcohol (hereinafter sometimes referred to as a "TBA-DMC catalyst"), a zinc hexacyanocobaltate complex in which the ligand is ethylene glycol dimethyl ether (sometimes referred to as a "glyme"), a zinc hexacyanocobaltate complex in which the ligand is diethylene glycol dimethyl ether (sometimes referred to as a "diglyme"), etc. These may be used alone or in combination of two or more.
Among these, the TBA-DMC catalyst is preferred from the viewpoint of having higher activity during polymerization and being able to narrow the Mw/Mn of the polyoxyalkylene diol described below, thereby enabling a lower viscosity.

The amount of the ring-opening addition polymerization catalyst to be added is not particularly limited as long as it is an amount necessary for the ring-opening polymerization of the cyclic ether, but it is preferably as small as possible, and is preferably 0.001 to 10 parts by mass, more preferably 0.01 to 1 part by mass, and particularly preferably 0.02 to 0.20 parts by mass, relative to 100 parts by mass of the polyoxyalkylene diol.
The smaller the amount of the ring-opening addition polymerization catalyst used in the ring-opening polymerization reaction of the cyclic ether, the smaller the amount of the ring-opening addition polymerization catalyst contained in the product polyoxyalkylene diol, which reduces the effect of the ring-opening addition polymerization catalyst on the reactivity of the polyoxyalkylene diol with the polyisocyanate compound.

For ring-opening addition polymerization using a ring-opening addition polymerization catalyst, the manufacturing conditions described in, for example, WO 2003/062301, WO 2004/067633, JP 2004-269776, JP 2005-15786, WO 2013/065802, and JP 2015-010162 can be adopted.

<Polyoxyalkylene Diol>
The polyoxyalkylene diol is a compound capable of producing a polyurethane resin precursor by reacting with a polyisocyanate compound.

The Mn of the polyoxyalkylene diol is not particularly limited, but is preferably 450 to 40,000, more preferably 450 to 35,000, even more preferably 500 to 30,000, still more preferably 550 to 24,000, and particularly preferably 1,500 to 9,500.
When the Mn of the polyoxyalkylene diol is not less than the above lower limit, the tensile properties and mechanical strength of a polyurethane resin obtained by using the polyoxyalkylene diol in a film are improved. When the Mn is not more than the above upper limit, the mixability with the polyisocyanate compound is improved, and the polyurethane resin is more likely to react with the polyisocyanate compound.

The Mw/Mn of the polyoxyalkylene diol is not particularly limited, but is preferably 1.00 to 3.00, more preferably 1.01 to 2.50, even more preferably 1.02 to 2.20, still more preferably 1.03 to 2.00, and particularly preferably 1.10 to 1.60.
When the Mw/Mn of the polyoxyalkylene diol is at least the lower limit, the tensile properties and mechanical strength are improved, and when it is no more than the upper limit, the viscosity tends to be low and the polyoxyalkylene diol is easy to handle.

The viscosity of the polyoxyalkylene diol at 25°C is not particularly limited, but is preferably 100 to 100,000 mPa·s, more preferably 300 to 80,000 mPa·s, even more preferably 500 to 80,000 mPa·s, still more preferably 500 to 60,000 mPa·s, particularly preferably 800 to 6,600 mPa·s, and especially preferably 1,100 to 6,600 mPa·s.
When the viscosity of the polyoxyalkylene diol at 25°C is equal to or higher than the above lower limit, the tensile properties and mechanical strength of a polyurethane resin obtained by using the polyoxyalkylene diol in a film are improved. When the viscosity is equal to or lower than the above upper limit, the mixability with the polyisocyanate compound is improved, and the polyurethane resin is more likely to react with the polyisocyanate compound.
The "viscosity" here is measured in the same manner as in the examples.

The structure of the polyoxyalkylene diol is not particularly limited, and examples thereof include a structure represented by the following formula I when a polycarbonate diol which is a condensation polymerization product of two or more types of alcohols and a carbonate compound is used, and a structure represented by the following formula I2 when a polycarbonate diol which is a reaction product of one or more types of alcohols and one or more types of cyclic esters with a carbonate compound is used.
HO-(R ² O) _s -(R ³ -OC(=O)-O) _u -R ³⁰ -(OR ² ) _t -OH...Formula I
HO-(R ² O) _s -(R ³ -OC(=O)-O) _u (R ³³ -C(=O)-O) _u2 -R ³⁴ -(OR ² ) _t -OH...Formula I2

R ³ and preferred embodiments thereof in formula I are the same as R ³ in formula A.
Furthermore, R ³⁰ and preferred embodiments thereof in formula I are the same as R ³⁰ in formula A.
In addition, u and preferred embodiments thereof in formula I are the same as u in formula A.
^R3 and preferred embodiments thereof in formula I2 are the same as ^R3 in formula A2.
Furthermore, R ³³ and preferred embodiments thereof in formula I2 are the same as R ³³ in formula A2.
Furthermore, R ³⁴ and preferred embodiments thereof in formula I2 are the same as R ³⁴ in formula A2.
Moreover, u and preferred embodiments thereof in formula I2 are the same as u in formula A2.
In addition, u2 and preferred embodiments thereof in formula I2 are the same as u2 in formula A2.

In formula I and formula I2, R ² is an alkylene group having 2 to 4 carbon atoms, and s and t are integers of 1 or more.
In formula I and formula I2, s and t are appropriately adjusted according to the Mn of the polycarbonate diol that is the raw material of the polyoxyalkylene diol and the carbon number of ^R2 so that the Mn of the polyoxyalkylene diol falls within the above range.
In formula I and formula I2, s and t may be the same or different values, but it is preferable that they are approximately the same value in order to facilitate setting of production conditions.

In the polyoxyalkylene diol, the ratio of the number of moles of carbonate groups represented by -OC(=O)O- to the total number of moles of oxyalkylene units represented by (R ² O) units and (OR ² ) [carbonate groups/oxyalkylene units] is not particularly limited, but is preferably 0.01 to 3, more preferably 0.1 to 2, from the viewpoint of the tensile properties and mechanical strength when a polyurethane resin obtained by using the polyoxyalkylene diol is formed into a film.
The ratio of [carbonate group/oxyalkylene unit] in the polyoxyalkylene diol is determined by ¹ H-NMR.
Specifically, polyoxyalkylene diol is dissolved in deuterated chloroform to a concentration of 10% by mass, and ^1H -NMR is measured with a resolution of 400 MHz (product name: JNM-ECZ400SJNM, manufactured by JEOL Ltd.), and calculation is performed based on the peak due to hydrogen bonded to the carbon adjacent to the carbonate group and the hydrogen bonded to the carbon not adjacent to the carbonate group (hydrogen in the oxyalkylene unit).

The number of carbon atoms in ^R2 in formula I and formula I2 is preferably 2 or 3, and more preferably 3.
There are no particular limitations on R ² O, but an oxypropylene group is preferred from the viewpoints that the resulting polyoxyalkylene diol will be easier to handle and less prone to phase separation.
Each of (R ² O) _s and (OR ² ) _t may contain two or more kinds of oxyalkylene groups, and when two or more kinds of oxyalkylene groups are contained, a combination of an oxypropylene group and an oxyethylene group is preferred.

When (R ² O) _s is composed of two or more kinds of oxyalkylene groups, the arrangement may be random, block, or a combination of both random and block.
When (OR ² ) _t is composed of two or more kinds of oxyalkylene groups, the arrangement may be random, block, or a combination of both random and block.

When the unit based on polyoxyalkylene diol is analyzed in more detail, the polyoxyalkylene diol is placed in a pressure-resistant container coated with polytetrafluoroethylene together with a 20% by mass sodium hydroxide solution and heated at 190°C for 19 hours. Thereafter, the mixture is extracted with a mixed solution of hexane/water (50/50 (mass ratio)), allowed to stand and separated, and the hexane layer is taken out. The hexane is distilled off from this hexane layer, and the obtained component is dissolved in tetrahydrofuran to obtain a measurement solution, which is measured by preparative GPC (LC-Force, product name of YMC Co., Ltd.), and the measurement solution corresponding to each of the two peaks obtained is separated.
The measurement solution corresponding to each peak is separated, dried to remove tetrahydrofuran, and then analyzed by ¹ H NMR, thereby identifying which of the peaks is a unit based on an alcohol and a cyclic ester, and which is a unit based on a carbonate compound, and determining the content ratio of each component by GPC.

The ratio of Mn of the polyoxyalkylene diol to Mn of the polycarbonate diol [Mn of polyoxyalkylene diol/Mn of polycarbonate diol] is not particularly limited, but is preferably 1.0 to 20, more preferably 1.1 to 15, and particularly preferably 1.15 to 12.

The polyoxyalkylene polycarbonate diol of the present invention can also be used as a raw material for polyhydroxyurethane resin. For example, epoxy groups are added to the terminals of the polyoxyalkylene polycarbonate diol of the present invention in the same manner as described in paragraphs 0026 to 0034 of Japanese Patent No. 3,114,304 and in Example 1 of Japanese Patent Publication No. 7-116171. Next, the epoxy groups at the terminals of the polyoxyalkylene polycarbonate diol of the present invention are reacted with carbon dioxide in the same manner as described in paragraphs 0034 to 0043 of Japanese Patent No. 5,277,233 to obtain a cyclic carbonate compound. Furthermore, the cyclic carbonate group of the cyclic carbonate compound is reacted with an amine compound in the same manner as described in paragraphs 0044 to 0050 of Japanese Patent No. 5,277,233 to obtain a polyhydroxyurethane resin.

(Method for producing polyurethane resin precursor)
The method for producing a polyurethane resin precursor of the present invention is a method for reacting the polyoxyalkylene diol obtained by the method for producing a polyoxyalkylene diol of the present invention with a polyisocyanate compound, thereby obtaining a polyurethane resin precursor.

<Polyisocyanate Compound>
The polyisocyanate compound is not particularly limited as long as it is a compound having a plurality of isocyanate groups in one molecule. As the polyisocyanate compound, a diisocyanate compound having two isocyanate groups in one molecule is preferable.
Examples of diisocyanate compounds include aromatic diisocyanate compounds such as 4,4'-diphenylmethane diisocyanate (hereinafter sometimes referred to as "MDI"), naphthalene-1,5-diisocyanate, polyphenylene polymethylene diisocyanate, 2,4-tolylene diisocyanate, and 2,6-tolylene diisocyanate; aralkyl diisocyanate compounds such as tetramethyl xylylene diisocyanate and xylylene diisocyanate; aliphatic diisocyanate compounds such as hexamethylene diisocyanate; alicyclic diisocyanate compounds such as isophorone diisocyanate and 4,4'-methylenebis(cyclohexyl isocyanate); urethane modified compounds obtained from diisocyanate compounds; biuret modified compounds; allophanate modified compounds; carbodiimide modified compounds; isocyanurate modified compounds; and the like. These may be used alone or in combination of two or more.
Among these, from the viewpoint of reactivity with polyoxyalkylene diol, aromatic diisocyanate compounds are preferred, and 4,4'-diphenylmethane diisocyanate is more preferred. Furthermore, from the viewpoint of suppressing yellowing over time, aliphatic diisocyanate compounds and alicyclic diisocyanate compounds are preferred, and hexamethylene diisocyanate and isophorone diisocyanate are more preferred.
Examples of compounds having two or more isocyanate groups in one molecule include polymeric MDI, biuret form of hexamethylene diisocyanate, nurate form of hexamethylene diisocyanate, nurate form of isophorone diisocyanate, trimethylolpropane adduct of hexamethylene diisocyanate, trimethylolpropane adduct of isophorone diisocyanate, and trimethylolpropane adduct of 2,4-tolylene diisocyanate.

The isocyanate group index, which is the ratio of isocyanate groups in a polyisocyanate compound to hydroxyl groups in a polyoxyalkylene diol ((the number of isocyanate groups contained in a polyisocyanate compound)/(the number of hydroxyl groups contained in a polyoxyalkylene diol)×100), is not particularly limited, but is preferably 150 to 300, and more preferably 180 to 280.
The amount of the polyisocyanate compound to be reacted with the polyoxyalkylene diol is preferably in excess, since an excessive amount of the polyisocyanate compound can be used to obtain a polyurethane resin precursor having isocyanate groups at both ends.

The molecular weight of the polyisocyanate compound is not particularly limited, but is preferably 120-400, more preferably 130-390, and particularly preferably 140-380.
When the molecular weight of the polyisocyanate compound is equal to or more than the above lower limit, the reactivity with polyoxyalkylene diol becomes better, and the tensile properties and mechanical strength of a polyurethane resin obtained by using the polyisocyanate compound in a film become better. When the molecular weight is equal to or less than the above upper limit, the tensile properties and mechanical strength of a polyurethane resin obtained by using the polyisocyanate compound in a film become better.

A reaction catalyst may be used when reacting the polyoxyalkylene diol with the polyisocyanate compound. When a reaction catalyst is used when reacting the polyoxyalkylene diol with the polyisocyanate compound, the reaction catalyst is not particularly limited, and examples thereof include known urethane reaction catalysts such as organic tin compounds such as dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dioctoate, and tin 2-ethylhexanoate; iron compounds such as iron acetylacetonate and ferric chloride; and tertiary amine catalysts such as triethylamine and triethylenediamine. These may be used alone or in combination of two or more.
Among these, organotin compounds are preferred from the viewpoint of better reactivity.
When a reaction catalyst is used in reacting the polyoxyalkylene diol with the polyisocyanate compound, the amount of the reaction catalyst to be added is not particularly limited, but is preferably 0.001 to 5 parts by mass, more preferably 0.005 to 0.1 parts by mass, and particularly preferably 0.01 to 0.05 parts by mass, relative to 100 parts by mass of the polyoxyalkylene diol.
When the amount of the reaction catalyst added is equal to or more than the above lower limit, the reactivity is superior, and when it is equal to or less than the above upper limit, the storage stability is superior.

The temperature at which the polyoxyalkylene diol and the polyisocyanate compound are reacted is not particularly limited, but is preferably 15 to 120°C, more preferably 30 to 100°C, and particularly preferably 50 to 90°C.
When the temperature during the reaction of the polyoxyalkylene diol with the polyisocyanate compound is equal to or higher than the above lower limit, the reaction is easily initiated reliably, whereas when the temperature is equal to or lower than the above upper limit, the reaction is easily controlled.

The reaction time when reacting the polyoxyalkylene diol with the polyisocyanate compound is not particularly limited, but is preferably 0.1 to 100 hours, more preferably 1 to 10 hours, and particularly preferably 3 to 5 hours.
When the reaction time is equal to or more than the lower limit, the reaction proceeds more efficiently, and when the reaction time is equal to or less than the upper limit, the reaction is more economical.

When the polyoxyalkylene diol is reacted with the polyisocyanate compound, a solvent may be used.
The solvent is not particularly limited, and examples of the solvent include solvents inert to the reaction, such as ethers such as tetrahydrofuran and dioxane, amides such as dimethylformamide and dimethylacetamide, sulfoxides such as dimethylsulfoxide, ketones such as acetone, methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, secondary alcohols such as isopropyl alcohol, and aromatic hydrocarbons such as toluene and xylene. These may be used alone or in combination of two or more.

Specific methods for reacting polyoxyalkylene diol with a polyisocyanate compound include, for example, the method described in International Publication No. 2006/043569.

<Polyurethane resin precursor>
The polyurethane resin precursor is a precursor of a polyurethane resin that can give a polyurethane resin by reacting with a chain extender.
The Mn of the polyurethane resin precursor is not particularly limited, but is preferably 600 to 120,000, more preferably 650 to 110,000, further preferably 700 to 95,000, and particularly preferably 750 to 50,000.
When the Mn of the polyurethane resin precursor is not less than the above lower limit, the tensile properties and mechanical strength of a polyurethane resin obtained by using the polyurethane resin precursor in a film form are better. When the Mn is not more than the above upper limit, the tensile properties of a polyurethane resin obtained by using the polyurethane resin precursor in a film form are better.

The structure of the polyurethane resin precursor is not particularly limited, but examples thereof include a structure represented by the following formula J.
OCN-(Q-NH-C(=O)-LC(=O)-NH) _n -Q-NCO...Formula J
In formula J, L is a group obtained by removing hydrogen atoms from both ends of a polyoxyalkylene diol represented by formula I or formula I2, Q is a group obtained by removing NCO groups from both ends of a polyisocyanate compound, and n is an integer of 1 or more.
In formula J, n is appropriately adjusted depending on the Mn of the polyoxyalkylene diol and the molecular weight of the polyisocyanate compound so that the Mn of the polyurethane resin precursor falls within the above range.

The polyurethane resin precursor can be widely used in foams, elastomers, coatings, elastic fibers, adhesives, pressure sensitive adhesives, binders, active energy ray curable resin compositions, medical materials, sealants, synthetic leather, artificial leather, coating agents, flooring materials, etc.
For example, the elastomer can be used for applications described in paragraphs 0114 to 0117 of JP 2017-133024 A, the coating material can be used for applications described in paragraphs 0118 and 0119 of JP 2017-133024 A, and the elastic fiber can be used for applications described in paragraphs 0125 to 0127 of JP 2017-133024 A. In addition, the adhesive can be used for applications described in paragraphs 0120 to 0123 of JP 2017-133024 A, the binder can be used for applications described in paragraph 0124 of JP 2017-133024 A, and the active energy ray curable resin composition can be used for applications described in paragraphs 0130 to 0135 of JP 2017-133024 A. The medical material can be used for the applications described in paragraph 0129 of JP 2017-133024 A, and the sealant can be used for the applications described in paragraph 0128 of JP 2017-133024 A.
As components other than the polyurethane resin precursor in the paint, the same components as those in the clear coat paint composition and colored paint composition described below can be used, and as components other than the polyurethane resin precursor in the pressure-sensitive adhesive, the same components as those in the pressure-sensitive adhesive composition described below can be used.

(Method of producing polyurethane resin)
The method for producing a polyurethane resin of the present invention is a method for producing a polyurethane resin precursor by the method for producing a polyurethane resin precursor of the present invention, and using the obtained polyurethane resin precursor to produce a polyurethane resin. Thereby, a polyurethane resin is obtained.
The method for producing a polyurethane resin is, for example, a method for producing a polyurethane resin by reacting a polyurethane resin precursor with a chain extender.

<Chain extender>
When a chain extender is used, the chain extender is preferably at least one selected from the group consisting of polyols having at least two active hydrogens that react with isocyanate groups and polyamines having at least two active hydrogens that react with isocyanate groups. The chain extender more preferably has a divalent hydrocarbon group having 2 to 12 carbon atoms, or a divalent hydrocarbon group having 2 to 12 carbon atoms that contains an etheric oxygen atom between the carbon atoms. The divalent hydrocarbon group may be linear or branched, or may have a ring structure.

Examples of divalent hydrocarbon groups having 2 to 12 carbon atoms include ethylene, n-propylene, n-butylene, n-hexylene, n-heptylene, n-octylene, n-dodecylene, cyclohexylene, and 2,2-dimethylpentylene.

The structure of the chain extender is not particularly limited, but examples thereof include a structure represented by the following formula K.
HO-R ¹ -OH...Formula K
R ¹ in formula K is a divalent hydrocarbon group having 2 to 12 carbon atoms (preferably 2 to 8 carbon atoms) or a divalent hydrocarbon group having 2 to 12 carbon atoms (preferably 2 to 8 carbon atoms) containing an etheric oxygen atom between carbon atoms. The divalent hydrocarbon group may be linear or branched, or may have a ring structure.

Specific examples of the chain extender are not particularly limited, and include linear 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; 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-heptanediol, 1 diols having a branched chain such as 2,4-dimethylolhexane, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, dimer diol, and neopentyl glycol; diols having an ether group such as diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, and tripropylene glycol; 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,4- Diols having an alicyclic structure, such as dihydroxycyclohexane and 1,4-dihydroxyethylcyclohexane; diols having an aromatic group, such as xylylene glycol, 1,4-dihydroxyethylbenzene and 4,4'-methylenebis(hydroxyethylbenzene); polyols, such as glycerin, trimethylolpropane and pentaerythritol; hydroxyamines, such as N-methylethanolamine and N-ethylethanolamine; ethylenediamine, 1,3-diaminopropane, hexamethylenediamine, triethylenetetramine, diethylenetriamine, etc. Examples of the polyamines include polyamines such as diamine, isophoronediamine, 4,4'-diaminodicyclohexylmethane, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, 4,4'-diphenylmethanediamine, methylenebis(o-chloroaniline), xylylenediamine, diphenyldiamine, tolylenediamine, hydrazine, piperazine, and N,N'-diaminopiperazine. These may be used alone or in combination of two or more.
Among these, ethylene glycol, propylene glycol, 1,4-butanediol, and 1,6-hexanediol are preferred, and 1,4-butanediol is more preferred.

The molecular weight of the chain extender is not particularly limited, but is preferably less than 300, and more preferably 60 or more and less than 300.
When the molecular weight of the chain extender is within the above preferred range, the tensile properties and mechanical strength of the resulting polyurethane resin when made into a film can be improved.

When a chain extender is used, the amount of the chain extender to be charged is not particularly limited, but is preferably 1.5 to 10 parts by mass, more preferably 2.5 to 7 parts by mass, and particularly preferably 3.5 to 5 parts by mass, relative to 100 parts by mass of the polyurethane resin precursor.
When the amount of the chain extender charged is equal to or more than the lower limit, the reaction can be reliably initiated, and when the amount is equal to or less than the upper limit, the amount of unreacted chain extender remaining can be suppressed.

<Hard segment content>
The hard segment content is not particularly limited, but is preferably from 5 to 40% by mass, and more preferably from 10 to 35% by mass.
When the hard segment content is equal to or more than the above lower limit, a urethane resin having better elongation properties can be obtained, and when the hard segment content is equal to or less than the above upper limit, a urethane resin having high mechanical strength can be obtained.
The hard segment content is a value (mass%) obtained by calculation using the formula "(mass of polyisocyanate compound+mass of chain extender)/(mass of polyisocyanate compound+mass of chain extender+mass of polyoxyalkylene diol)×100".

<NCO Unit Content>
The NCO unit content is not particularly limited, but is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, and particularly preferably 12 to 28% by mass.
When the NCO unit content is equal to or more than the above lower limit, the tensile properties of the polyurethane resin when formed into a film are better, and when the NCO unit content is equal to or less than the above upper limit, the elongation properties of the polyurethane resin when formed into a film are better.
The NCO unit content is a value (% by mass) calculated using the formula "(mass of polyisocyanate compound)/(mass of polyisocyanate compound+mass of chain extender+mass of polyoxyalkylene diol)×100".

A urethanization reaction catalyst may be used when reacting the polyurethane resin precursor with the chain extender. When a urethanization reaction catalyst is used when reacting the polyurethane resin precursor with the chain extender, the urethanization reaction catalyst is not particularly limited, and examples thereof include organic tin compounds such as dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dioctoate, and tin 2-ethylhexanoate; iron compounds such as iron acetylacetonate and ferric chloride; and tertiary amine catalysts such as triethylamine and triethylenediamine. These may be used alone or in combination of two or more.
Among these, organotin compounds are preferred from the viewpoint of better reactivity.

When a urethanization reaction catalyst is used, the amount of the urethanization reaction catalyst added is not particularly limited, but is preferably 0.0001 to 1.0 part by mass, and more preferably 0.001 to 0.01 part by mass, per 100 parts by mass of the polyurethane resin precursor and the chain extender combined.

The temperature at which the polyurethane resin precursor is reacted with the chain extender is not particularly limited, but is preferably 20 to 160°C, more preferably 60 to 150°C, and particularly preferably 90 to 140°C.
When the temperature during the reaction of the polyurethane resin precursor with the chain extender is equal to or higher than the above lower limit, the reaction can be reliably initiated. When the temperature is equal to or lower than the above upper limit, side reactions are unlikely to occur and a high molecular weight is likely to be obtained.

The reaction time when reacting the polyurethane resin precursor with the chain extender is not particularly limited, but is preferably 0.1 to 100 hours, more preferably 1 to 10 hours, and particularly preferably 2 to 5 hours.
When the reaction time is equal to or more than the lower limit, the reaction is excellent in terms of performance, and when the reaction time is equal to or less than the upper limit, the reaction is economically excellent.

The reaction between the polyurethane resin precursor and the chain extender may be carried out in an organic solvent.
When the reaction between the polyurethane resin precursor and the chain extender is carried out in an organic solvent, a polyurethane resin solution in which the polyurethane resin is dissolved in the organic solvent is obtained.
The organic solvent is not particularly limited, and examples thereof include dimethylformamide, dimethylacetamide, dimethylsulfoxide, methyl ethyl ketone, cyclohexanone, ethyl acetate, isopropyl alcohol, etc. These may be used alone or in combination of two or more.

Specific methods for reacting a polyurethane resin precursor with a chain extender include, for example, the methods described in WO 2008/149682, WO 2011/122178, JP 2015-057468, etc.

(Polyurethane resin)
The polyurethane resin of the present invention is obtained by the method for producing a polyurethane resin of the present invention.
The polyurethane resin of the present invention has units based on a polyoxyalkylene diol and units based on a polyisocyanate compound, and further has units based on a chain extender, as necessary.
The unit based on a polyoxyalkylene diol is a unit based on a polyoxyalkylene diol obtained by polymerizing a polycarbonate diol and a cyclic ether.

The proportion of each unit in the polyurethane resin can be determined, for example, as follows.
The polyurethane resin is placed in a pressure-resistant container coated with polytetrafluoroethylene together with pyridine and distilled water, and heated for 15 hours at 130° C. Thereafter, the pyridine is distilled off to obtain a solution in tetrahydrofuran.
This solution is used as a measurement solution and is measured by the above-mentioned preparative GPC, and the measurement solution is fractionated to correspond to each of the three peaks obtained.
For each of the sample solutions corresponding to the three peaks, tetrahydrofuran is removed by drying under reduced pressure at 80° C. for 1 hour, and each of the remaining liquids is analyzed by ¹ H-NMR. This identifies which of the peaks is a unit based on the polyisocyanate compound, which is a unit based on the chain extender, and which is a unit based on the polyoxyalkylene diol, and the content ratio of each component is determined by GPC.

The Mn of the polyurethane resin is not particularly limited, but is preferably more than 800, more preferably from 1,000 to 120,000, even more preferably from 1,100 to 100,000, and particularly preferably from 73,000 to 97,000.
When the Mn of the polyurethane resin is at least the above lower limit, the elongation properties when made into a film are better, and when it is no greater than the above upper limit, the tensile properties when made into a film are better.

The glass transition temperature Tg of the polyurethane resin is not particularly limited, but is preferably from -60 to 0°C, more preferably from -55 to -10°C, and particularly preferably from -50 to -25°C.
When the glass transition temperature Tg of the polyurethane resin is within the above preferred range, the polyurethane resin has excellent low-temperature properties.

The flow initiation temperature of the polyurethane resin is not particularly limited, but is preferably 120 to 210°C, more preferably 130 to 200°C, further preferably 140 to 190°C, and particularly preferably 145 to 180°C.
When the flow starting temperature of the polyurethane resin is equal to or higher than the above lower limit, the heat resistance is excellent, and when the flow starting temperature is equal to or lower than the above upper limit, the injection moldability is excellent.

The structure of the polyurethane resin is not particularly limited, but examples thereof include a structure represented by the following formula L.
H-(E-C(=O)-NH-J-NH-C(=O)-) _m -E-H...Formula L
In formula L, J is a group obtained by removing NCO groups at both ends from a polyurethane resin precursor represented by formula J, E is a group obtained by removing hydrogen atoms at both ends from a chain extender represented by formula K, and m is an integer of 1 or more.
In formula L, m is appropriately adjusted according to the Mn of the polyurethane resin precursor and the molecular weight of the chain extender so that the Mn of the polyurethane resin falls within the above range.

(Polyurethane resin composition)
The polyurethane resin composition of the present invention is a composition containing the polyurethane resin of the present invention. The polyurethane resin composition of the present invention may contain, in addition to the polyurethane resin of the present invention, additives such as a filler (reinforcing agent), a stabilizer, a pigment (inorganic pigment, organic pigment), a flame retardant, a release agent, and a fungicide, if necessary.

<Filler (reinforcing agent)>
The filler (reinforcing agent) is not particularly limited, and examples thereof include carbon black, aluminum hydroxide, calcium carbonate, titanium oxide, silica, glass, bone powder, wood powder, fiber flakes, etc. These may be used alone or in combination of two or more.

<Stabilizer>
The stabilizer is not particularly limited, and examples thereof include anti-aging agents such as antioxidants and ultraviolet absorbers; light stabilizers; etc. These may be used alone or in combination of two or more.

The antioxidant is not particularly limited, and examples thereof include butylhydroxytoluene (BHT).
hindered phenol compounds such as these, benzotriazole compounds, hindered amine compounds, butylhydroxyanisole (BHA), diphenylamine, phenylenediamine, triphenyl phosphite, etc. These may be used alone or in combination of two or more.

<Pigments>
The inorganic pigment is not particularly limited, and examples thereof include titanium dioxide, zinc oxide, ultramarine, red iron oxide, lithopone, lead, cadmium, iron, cobalt, aluminum, hydrochloride, sulfate, etc. These may be used alone or in combination of two or more.
The organic pigment is not particularly limited, and examples thereof include azo pigments, copper phthalocyanine pigments, etc. These may be used alone or in combination of two or more.

<Flame retardants>
The flame retardant is not particularly limited, and examples thereof include chloroalkyl phosphate, dimethyl methyl phosphonate, ammonium polyphosphate, organic bromine compounds, etc. These may be used alone or in combination of two or more.

<Release Agent>
The releasing agent is not particularly limited, and examples thereof include wax, soaps, silicone oil, etc. These may be used alone or in combination of two or more kinds.

<Antifungal agent>
The antifungal agent is not particularly limited, and examples thereof include pentachlorophenol, pentachlorophenol laurate, bis(tri-n-butyltin)oxide, etc. These may be used alone or in combination of two or more.

The polyurethane resin composition of the present invention contains a polyurethane resin that has good compatibility and suppresses the variation and deterioration of physical properties, and therefore can be suitably used in paint compositions, pressure sensitive adhesive compositions, printing ink compositions, adhesive compositions, porous films formed on nonwoven fabrics for artificial leather, tire compositions, elastomers, elastic fibers, binders, active energy ray curable resin compositions, medical materials, sealants, coating agents, foams, flooring materials, etc. In particular, when the polyurethane resin composition of the present invention is applied to tire compositions, tires with excellent steering stability on icy roads, etc. can be obtained.

The elastomer can be used for applications described in paragraphs 0114 to 0117 of JP 2017-133024 A, and the elastic fiber can be used for applications described in paragraphs 0125 to 0127 of JP 2017-133024 A. The binder can be used for applications described in paragraph 0124 of JP 2017-133024 A, and the active energy ray curable resin composition can be used for applications described in paragraphs 0130 to 0135 of JP 2017-133024 A. The medical material can be used for applications described in paragraph 0129 of JP 2017-133024 A, and the sealant can be used for applications described in paragraph 0128 of JP 2017-133024 A.

The polyurethane resin composition of the present invention may contain a solvent. The solvent may be either water or an organic solvent, or both.
When the polyurethane resin composition of the present invention contains water as a solvent, it may be an aqueous solution in which the polyurethane resin is dissolved in water, or an aqueous dispersion in which the polyurethane resin is dispersed in water. The aqueous dispersion may be a dispersion in which the polyurethane resin is dispersed in water by a surfactant, or a self-emulsifying dispersion in which the polyurethane resin is dispersed in water.
The dispersion liquid in which the polyurethane resin is dispersed in water by the surfactant may be, for example, a dispersion liquid obtained by forcibly emulsifying a polyurethane resin precursor obtained by reacting a polyoxyalkylene polycarbonate diol with a polyisocyanate compound in the presence of a surfactant and water by a method such as high-speed stirring, ultrasonic wave or high-pressure emulsification, and then reacting a chain extender. The surfactant is not particularly limited, but it is preferable to use a nonionic surfactant, and more preferably polyoxyalkylene monoalkyl ether, polyoxyalkylene monoalkenyl ether, polyoxyalkylene monoalkanopolyether, polyoxyethylene distyrylphenyl ether, polyoxyethylene propylene distyrylphenyl ether, polyoxyethylene tristyrylphenyl ether, polyoxyethylene propylene tristyrylphenyl ether, or Pluronic-type nonionic surfactant.
The self-emulsifying dispersion in which the polyurethane resin itself is dispersed in water may be a dispersion obtained by dispersing in water a polyurethane resin precursor obtained by reacting a polyoxyalkylene polycarbonate diol, a polyisocyanate compound, and a compound that exhibits ionicity in water, and then further reacting the polyurethane resin precursor with a chain extender.
Examples of compounds that exhibit ionicity in water include compounds having a sulfo group, compounds having a carboxy group, compounds having an amino group, compounds having a phosphate structure, and compounds having a quaternary ammonium salt structure. Specific examples of compounds that exhibit ionicity in water include 2-oxyethanesulfonic acid, phenolsulfonic acid, 3,4-diaminobutanesulfonic acid, 3,6-diamino-2-toluenesulfonic acid, 2-(2-aminoethylamino)ethanesulfonic acid, ethylenediaminepropylsulfonic acid, ethylenediaminebutylsulfonic acid, 1,2- or 1,3-propylenediamine-β-ethylsulfonic acid, 2-(3-aminopropylamino)ethanesulfonic acid, 2, Examples of such compounds include compounds having a sulfo group, such as 4-diaminobenzenesulfonic acid; dihydroxycarboxylic acids, such as 2,2-dimethylollactic acid, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, and 2,2-dimethylolvaleric acid; compounds having a sulfo group and a carbonyl group, such as sulfobenzoic acid, sulfosuccinic acid, and 5-sulfoisophthalic acid; and compounds having a sulfo group and an amino group, such as sulfanilic acid and 1,3-phenylenediamine-4,6-disulfonic acid.
As a method for obtaining a dispersion in which a polyurethane resin is dispersed in water by an emulsifier and a self-emulsified dispersion in which a polyurethane resin itself is dispersed in water, for example, the methods described in JP-A-2001-354742 and JP-A-2019-112564 can be used.
When the polyurethane resin composition of the present invention contains water as a solvent, the composition can be used for paints, ink binders, coating agents, pressure sensitive adhesives, adhesives, artificial leathers, synthetic leathers, and the like.
The polyurethane resin composition of the present invention may contain a polyurethane resin solution in which the polyurethane resin of the present invention is dissolved in an organic solvent, or may be the polyurethane resin solution itself.

<Polyurethane resin solution>
The polyurethane resin solution may be obtained by reacting the polyurethane resin precursor of the present invention with a chain extender in an organic solvent as described above, or may be obtained by adding an organic solvent to a polyurethane resin that does not contain an organic solvent, or may be obtained by reacting the polyurethane resin precursor of the present invention with a chain extender in an organic solvent and then adding an organic solvent. The organic solvent is not particularly limited, and examples thereof include dimethylformamide, dimethylacetamide, dimethylsulfoxide, methyl ethyl ketone, cyclohexanone, ethyl acetate, isopropyl alcohol, toluene, methanol, and ethanol. These may be used alone or in combination of two or more.
Polyurethane resin solutions can be used as components of solvent-based two-component paints, moisture-curing one-component paints, blocked isocyanate-based solvent paints, alkyd resin paints, urethane-modified synthetic resin paints, and ultraviolet-curing paints.
The polyurethane resin solution can be used, for example, as a coating composition, a pressure sensitive adhesive composition, a printing ink composition, an adhesive composition, a composition for forming a surface skin layer, a composition for a porous coating, a composition for tires, and the like.

<<Paint composition>>
The coating composition may be a coating composition for a clear coat that does not contain a pigment, or may be a colored coating composition that contains a pigment.

The components other than the polyurethane resin in the clear coat coating composition are not particularly limited, and examples thereof include organic solvents, reactive diluents, transparent pigments, fillers, dyes, nanoparticles, light stabilizers, antioxidants, degassing agents, emulsifiers, slip additives, polymerization inhibitors, adhesion promoters, flow regulators, film formation aids, thickeners, slack regulators, flame retardants, corrosion inhibitors, catalysts, waxes, drying agents, biocides, matting agents, etc. These may be used alone or in combination of two or more.
The content of the polyurethane resin in the clear coat coating composition is not particularly limited, but is preferably 1 to 90% by mass, more preferably 20 to 85% by mass, and particularly preferably 40 to 80% by mass.

The components other than the polyurethane resin in the colored coating composition are not particularly limited, and examples thereof include organic solvents, reactive diluents, transparent pigments, fillers, dyes, nanoparticles, light stabilizers, antioxidants, degassing agents, emulsifiers, slip additives, polymerization inhibitors, adhesion promoters, flow regulators, film formation aids, thickeners, slack regulators, flame retardants, corrosion inhibitors, catalysts, waxes, drying agents, biocides, matting agents, etc. These may be used alone or in combination of two or more.
The content of the polyurethane resin in the colored coating composition is not particularly limited, but is preferably 1 to 90% by mass, more preferably 20 to 85% by mass, and particularly preferably 40 to 80% by mass.

<<Adhesive composition>>
The components other than the polyurethane resin in the pressure-sensitive adhesive composition are not particularly limited, and examples thereof include various additives such as organic solvents, catalysts, reaction accelerators, internal release agents, fillers, reinforcing agents, dyes, pigments, colorants, flame retardants, UV absorbers, antioxidants, hydrolysis resistance improvers, mildew inhibitors, and stabilizers; various fibers such as glass fibers and polyester fibers; inorganic components such as talc and silica; various coupling agents; etc. These may be used alone or in combination of two or more.
The content of the polyurethane resin in the pressure-sensitive adhesive composition is not particularly limited, but is preferably 1 to 90% by mass, more preferably 20 to 85% by mass, and particularly preferably 40 to 80% by mass.

<<Printing ink composition>>
The components other than the polyurethane resin in the printing ink composition are not particularly limited, and examples thereof include organic solvents, colorants, other additives, etc. These may be used alone or in combination of two or more.
The content of the polyurethane resin in the printing ink composition is not particularly limited, but is preferably from 1 to 90% by mass, more preferably from 20 to 85% by mass, and particularly preferably from 40 to 80% by mass.

<<Adhesive composition>>
The components other than the polyurethane resin in the adhesive composition are not particularly limited, and examples thereof include pigments, solvents, resins other than polyurethane resins, colorants, antiblocking agents, dispersion stabilizers, viscosity regulators, leveling agents, gelling inhibitors, light stabilizers, antioxidants, ultraviolet absorbers, heat resistance improvers, fillers, plasticizers, lubricants, antistatic agents, reinforcing materials, catalysts, auxiliaries, and other additives. These may be used alone or in combination of two or more. The solvent is not particularly limited as long as it is suitable for the characteristics of the polyurethane resin to be obtained, and both aqueous and organic solvents may be used.
The content of the polyurethane resin in the adhesive composition is not particularly limited, but is preferably 1 to 90% by mass, more preferably 20 to 85% by mass, and particularly preferably 40 to 80% by mass.
The adhesive composition can be used as a composition for forming a surface layer of synthetic leather and artificial leather, for bonding between layers, for food packaging, shoes, footwear, binders, decorative paper, wood, structural members, automobile members, etc. The adhesive composition can also be used as a component of low-temperature adhesives and hot melts.

<<Composition for forming epidermal layer>>
The composition for forming a skin layer can be used for synthetic leather, artificial leather, etc. The components other than the polyurethane resin in the composition for forming a skin layer are not particularly limited, and examples thereof include organic solvents, resins other than the polyurethane resin of the present invention, colorants, other additives, etc. These may be used alone or in combination of two or more.
The content of the polyurethane resin in the composition for forming the surface layer is not particularly limited, but is preferably 1 to 90% by mass, more preferably 20 to 85% by mass, and particularly preferably 40 to 80% by mass.

<<Porous Coating Composition>>
The porous coating composition can be used to form a porous coating that forms a nonwoven fabric for artificial leather. The components other than the polyurethane resin in the porous coating composition are not particularly limited, and examples thereof include organic solvents, resins other than polyurethane resins, colorants, other additives, etc. These may be used alone or in combination of two or more.
The content of the polyurethane resin in the porous coating composition is not particularly limited, but is preferably 1 to 90% by weight, more preferably 20 to 85% by weight, and particularly preferably 40 to 80% by weight.

<<Tire Composition>>
Examples of components in the tire composition other than the polyurethane resin of the present invention include catalysts, fillers, flame retardants, colorants such as pigments or dyes, antistatic agents, reinforcing fibers, antioxidants, and other additives. The tire composition may also contain fillers such as rubber, elastomers, thermoplastic resins, silica, calcium carbonate, and clay, antioxidants, oils, plasticizers, color formers, and weather resistance agents, as desired.
The tire composition preferably contains 1 to 80% by mass of the polyurethane resin of the present invention.
The tire composition is used in tires and tire components. Specifically, it is used in pneumatic tires and non-pneumatic tires or parts thereof. Examples of tire components include, but are not limited to, run-flat tire supports, airless tire supports, and tire frameworks.

(Goods)
The article of the present invention comprises the polyurethane resin composition of the present invention.
The article of the present invention may be composed entirely of the polyurethane resin composition of the present invention, or may be composed partially of the polyurethane resin composition of the present invention.
The embodiment in which a part of an article is constituted by the polyurethane resin composition of the present invention is not particularly limited, and examples thereof include a configuration in which a layer of the polyurethane resin composition is provided on the surface or inside, a configuration in which a layer impregnated with a polyurethane resin solution is provided on the surface or inside, and the like.
Examples of articles obtainable using the polyurethane resin composition of the present invention include coated articles, laminates, printed matter, synthetic leather, artificial leather, tires, and tire parts.
The coated article is an article in which the surface of a substrate is coated with a coating composition, which is the polyurethane resin composition of the present invention. The substrate is not particularly limited, but examples thereof include leather, textiles, resins such as vinyl chloride, acrylic resins, polystyrene, polypropylene, polyester, and polyurethane, metals, glass, paper, wood, cement, and rubber.
Examples of methods for applying the coating composition to the surface of an article to be coated include roll coating, spray coating, dip coating, spin coating, curtain coating, and die coating.

The polyurethane resin solution as the polyurethane resin composition of the present invention may be uniformly applied onto a substrate, dried, and peeled off from the substrate to be molded into a film, or may be poured into a mold to be molded into a film.
When the polyurethane resin composition of the present invention does not contain an organic solvent, it can be molded into a film or any other desired shape by heating it to melt or soften it and inserting it into a mold.
The uses of the articles molded into a film are not particularly limited, and examples thereof include elastic films used for paper diapers, dustproofing, etc.; general-purpose conveyor belts; various keyboard sheets; laminates; intermediate films for laminated glass; pressure-sensitive adhesives; cushioning materials; and multilayer actuator components.

When the article of the present invention is a film, its physical properties will be described below.
The storage modulus E' (-20°C) of the film is not particularly limited, but is preferably 0.1 to 1000 MPa, more preferably 0.5 to 300 MPa, and particularly preferably 1.0 to 50 MPa.
The storage modulus E' (0° C.) of the film is not particularly limited, but is preferably from 0.01 to 300 MPa, more preferably from 0.1 to 100 MPa, and particularly preferably from 0.5 to 25 MPa.
The storage modulus E' (25° C.) of the film is not particularly limited, but is preferably from 0.01 to 300 MPa, more preferably from 0.1 to 100 MPa, and particularly preferably from 0.3 to 15 MPa.
The glass transition temperature Tg of the film is not particularly limited, but is preferably from -100 to 10°C, more preferably from -70 to 0°C, and further preferably from -50 to -10°C.
The stress M100 when the film is stretched 100% is not particularly limited, but is preferably 1.0 to 6.0 MPa, more preferably 1.1 to 5.0 MPa, and particularly preferably 1.2 to 4.0 MPa.
The breaking strength Tmax of the film is not particularly limited, but is preferably 5 to 100 MPa, more preferably 8 to 70 MPa, and further preferably 10 to 50 MPa.
The breaking elongation L of the film is not particularly limited, but is preferably 400 to 1,500%, more preferably 500 to 1,300%, and particularly preferably 600 to 1,100%.
The "storage modulus E'", "glass transition temperature Tg", "stress at 100% elongation M100", "breaking strength Tmax" and "breaking elongation L" are measured in the same manner as in the examples.

Examples of articles obtained using the polyurethane resin composition of the present invention include coated articles, laminates, printed matter, synthetic leather, and artificial leather.

<Painted items>
A coated article is an article in which a coating composition is applied to the surface of a substrate.
The object to be coated is not particularly limited, and examples thereof include leather, textiles, resins such as polyvinyl chloride, acrylic resin, polystyrene, polypropylene, polyester, polyurethane, etc., metal, glass, paper, wood, cement, rubber, etc. These may be used alone or in combination of two or more.
The method for applying the coating composition to the surface of the substrate is not particularly limited, and examples thereof include roll coating, spray coating, dip coating, spin coating, curtain coating, die coating, etc. These may be used alone or in combination of two or more.

<Laminate>
The laminate is an article having a pressure-sensitive adhesive composition between layers.
The material of the substrate constituting each layer in the laminate is not particularly limited, and examples thereof include plastics such as polyethylene terephthalate, polyethylene naphthalate, acrylic resin, polycarbonate, polyamide, polyolefin, polyamide, polyvinyl chloride, polyimide, etc.; paper; metal foil; glass; etc. These may be used alone or in combination of two or more.
The method for applying the pressure-sensitive adhesive composition between the layers in the laminate is not particularly limited, and examples thereof include roll coating, die coating, silk screen, gravure coating, spin coating, dispenser, etc. These may be used alone or in combination of two or more.
Using the above-mentioned coating method, a laminate can be obtained by (a) a technique in which the adhesive composition is coated on one side of a substrate and another substrate is laminated on top of the coated adhesive composition under atmospheric pressure or reduced pressure conditions, or (b) a technique in which the adhesive composition is directly filled between the layers of the substrate using a dispenser.

<Printed materials>
A printed matter is an article in which a printing ink composition is printed on one or both sides of a printing substrate.
A printed matter can be obtained by applying the printing ink composition to a substrate to be printed by a method such as gravure coating, roll coating, die coating, curtain coating or spin coating, and, if necessary, heating or drying under reduced pressure to form a coating film.
The printing substrate is not particularly limited, and examples thereof include plastic films such as polyethylene terephthalate, polyamide, polyolefins (polyethylene, polypropylene, etc.), polystyrene, vinyl chloride, acrylic resin, etc., metal films such as aluminum foil, rubber, elastomers, etc. These may be used alone or in combination of two or more.

<Synthetic leather, artificial leather>
Synthetic leather and artificial leather can be obtained, for example, by impregnating the surface of a fiber substrate or a nonwoven fabric with a composition for forming a surface skin layer or a composition for a porous coating, and passing the resulting material through a water tank in a wet coagulation method, or by passing the material through a heated oven in a dry coagulation method.

The present invention will be described in detail below with reference to examples. However, the present invention is not limited to the following examples.

(Evaluation test)
<Molecular weight>
The Mn and Mw of the polyoxyalkylene diol (PCD+PO) obtained in each example described below were measured by gel permeation chromatography (GPC). The measurement results are shown in Table 1.
The solvent used was tetrahydrofuran, and the calibration curve was prepared using polypropylene glycol with a known hydroxyl value-based molecular weight. In other words, the molecular weight was calculated as a polypropylene glycol-based molecular weight.
The "hydroxyl value-based molecular weight" refers to a molecular weight calculated by applying the hydroxyl value calculated based on JIS K 1557 (2007) to the formula "[56,100/(hydroxyl value)]×2" in an oxyalkylene polymer containing a repeating unit based on an alkylene oxide monomer.

Furthermore, the Mn and Mw of the polyurethane resin obtained in each example described later were measured by GPC. The measurement results of Mn are shown in Table 2.
The solvent used was tetrahydrofuran, and the calibration curve was prepared using polystyrene with a known molecular weight. That is, the molecular weight was calculated as a polystyrene equivalent.

The "Propylene oxide (PO) charge amount" shown in Table 1 refers to the charge amount (parts by mass) of propylene oxide as a cyclic ether per 100 parts by mass of polycarbonate diol (PCD initiator).

<Calculation method for carbonate group content (hereinafter sometimes referred to as "content ratio")>
[Ratio of carbonate groups in one molecule of initiator PCD]
The content of carbonate groups in one molecule of the initiator PCD (G _(PCD) , mass%) was calculated from the following formula 1.
G _(PCD) = (60×A)/(Mn _(PCD) )×100...Formula 1
In the formula 1, the symbols have the following meanings, and "60" is the formula weight per carbonate group present in one molecule of the initiator PCD.
G _(PCD) : Content of carbonate group in one molecule of initiator PCD (% by mass)
A: Number of carbonate groups in one molecule of initiator PCD Mn _(PCD) : Mn of initiator PCD

In the above formula 1, A was calculated as follows in each of the cases where (a) the initiator PCD is composed of only two or more types of diols, and (b) the initiator PCD is composed of one or more types of diols and one or more types of cyclic esters.
(a) Initiator PCD Consists of Only Two or More Diols A in the above formula 1 was calculated from the following formula 2.
A=(Mn _(PCD) -C _(diol) -34)/(C _(diol) +60)...Formula 2
Here, the symbols in formula 2 have the following meanings, and the same symbols as in formula 1 have the same meanings as in formula 1. Furthermore, "34" is the total formula weight of the two terminal hydroxyl groups present in one molecule of the initiator PCD, and "60" is the formula weight per carbonate group present in one molecule of the initiator PCD.
C _(diol) : average of molecular weights (formula weights) of carbon chains (e.g., ^R3 or ^R30 in the above formula A) derived from each diol constituting the initiator PCD Here, "average of molecular weights (formula weights) of carbon chains derived from each diol constituting the initiator PCD" refers to a value obtained by calculating the product of the molecular weight (formula weight) of the carbon chain derived from each diol and the ratio (mol%) of all units derived from each diol to all units constituting the initiator PCD, and summing the values of the products calculated for each diol. Note that the carbon chain derived from each diol is a residue obtained by removing two hydroxyl groups from each diol, the total units constituting the initiator PCD are all the repeating units constituting the initiator PCD, and the total units derived from each diol are "all the repeating units derived from each diol (repeating units of "carbon chains derived from each diol + carbonate group")", and the same applies in the following explanation.
When the initiator PCD is obtained using diol A and diol B (where diol A/diol B=X/Y (molar ratio; X+Y=100)), the above "C _(diol) " is calculated by "molecular weight (formula weight) of carbon chain derived from diol A×X/100+molecular weight (formula weight) of carbon chain derived from diol B×Y/100". Specifically, when the initiator PCD is obtained using 1,5-pentanediol and 1,6-hexanediol (where 1,5-pentanediol/1,6-hexanediol (molar ratio: 50/50)), the above "C _(diol) " is "77", calculated by "70×50/100+84×50/100".
(b) In the case where the initiator PCD is composed of one or more diols and one or more cyclic esters, A in the above formula 1 was calculated from the following formula 3.
A = ((Mn _(PCD) - C _{ex (dEs)} ) / C _(dEs) ) × P...Formula 3
Here, the symbols in formula 3 have the following meanings, and the same symbols as those in formula 1 have the same meanings as those in formula 1.
P: The content ratio (mol%) of all units derived from each diol to all units constituting the initiator PCD
In addition, when the initiator PCD is an initiator PCD obtained using diol C and cyclic ester D (wherein diol C/cyclic ester D=Z/W (molar ratio; Z+W=100)), the above "P" corresponds to Z/100.
C _{ex (dEs)} : the sum of the average molecular weight (formula weight) of the "carbon chain derived from each diol and each cyclic ester (for example, R ³⁴ in the above formula A2)" that is directly bonded to the hydroxyl group at one end of the initiator PCD, and the formula weight (34) taking into account the terminal hydroxyl group in one molecule of the initiator PCD Here, the "average molecular weight (formula weight) of the carbon chain derived from each diol and each cyclic ester, which is directly bonded to the hydroxyl group at one end of the initiator PCD" refers to the product of the molecular weight (formula weight) of the carbon chain derived from each diol, which is directly bonded to the hydroxyl group at one end of the initiator PCD, and the ratio (mol%) of all units derived from each diol to all units constituting the initiator PCD, and the product of the molecular weight (formula weight) of the carbon chain derived from each cyclic ester, which is directly bonded to the hydroxyl group at one end of the initiator PCD, and the ratio (mol%) of all units derived from each cyclic ester to all units constituting the initiator PCD, and the total value of the products calculated for each diol and each cyclic ester is calculated. Note that the carbon chain derived from each cyclic ester is the residue obtained by removing the ester group from each cyclic ester, and the total units derived from each cyclic ester are "all of the repeating units derived from each cyclic ester (repeating units of "carbon chain derived from each cyclic ester + ester group")", and the same applies in the following explanation.
When the initiator PCD is an initiator PCD obtained using diol C and cyclic ester D (where diol C/cyclic ester D=Z/W (molar ratio; Z+W=100)), the above "C _ex(dEs)" is calculated as "(molecular weight (formula weight) of carbon chain derived from diol C×Z/100+molecular weight (formula weight) of carbon chain derived from cyclic ester D×W/100+34)". Specifically, when the initiator PCD is an initiator PCD obtained using 1,6-hexanediol and ε _- caprolactone (where 1,6-hexanediol/ε-caprolactone (molar ratio: 50/50)), the above "C ex(dEs)" is "111", calculated as "84×50/100+70×50/100+34".
C _(dEs) : average of molecular weights (formula weights) of units derived from each diol and each cyclic ester constituting the initiator PCD Here, "average of molecular weights (formula weights) of units derived from each diol and each cyclic ester constituting the initiator PCD" refers to the product of the molecular weight (formula weight) of the units derived from each diol constituting the initiator PCD and the content ratio (mol %) of all units derived from each diol to all units constituting the initiator PCD, calculating the product of the molecular weight (formula weight) of the units derived from each cyclic ester constituting the initiator PCD and the content ratio (mol %) of all units derived from each cyclic ester constituting the initiator PCD to all units constituting the initiator PCD, and summing up the values of these products calculated for each diol and each cyclic ester.
When the initiator PCD is obtained using diol C and cyclic ester D (wherein diol C/cyclic ester D=Z/W (molar ratio; Z+W=100)), the above "C _(dEs) " is calculated as "(molecular weight (formula weight) of all units derived from diol C×Z/100+molecular weight (formula weight) of all units derived from cyclic ester D×W/100)." Specifically, when the initiator PCD is obtained using 1,6-hexanediol and ε-caprolactone (wherein 1,6-hexanediol/ε-caprolactone (molar ratio: 50/50)), the above "C _(dEs) " is "129," calculated as "144×50/100+114×50/100."

[Ratio of carbonate groups in polyoxyalkylene diol (PCD + PO)]
The content of carbonate groups in the polyoxyalkylene diol (G _(PCD+PO), mass %) was calculated from the following formula 7.
G _(PCD+PO) = (A×60)/(Mn _(PCD+PO) )×100...Equation 7
In the formula 7, the meaning of each symbol is as follows, and the same symbols as those in the formula 1 have the same meaning as those in the formula 1.
G _{(PCD + PO)} : Content of carbonate groups in PCD + PO (mass%)
Mn _(PCD+PO) : Mn of PCD+PO

<Viscosity>
The viscosity (unit: mPa·s) at 25° C. of the polyoxyalkylene diol (PCD+PO) obtained in each synthesis example described later was measured using an E-type viscometer (product name: VISCOMETER TV-22, manufactured by Toki Sangyo Co., Ltd.). The measurement results are shown in Table 1.

<Evaluation of Phase Separation>
The polyoxyalkylene diols (PCD+PO) obtained in each synthesis example described below were heated at 80° C. for 1 hour and then thoroughly mixed. After that, the mixture was left to stand at 23° C. for 1 week, and the phase separation of the polyoxyalkylene diol was evaluated visually. The evaluation results are shown in Table 1. The evaluation criteria were as follows.
<<Evaluation criteria>>
A: The liquid is transparent and free of precipitates without being separated into two or more layers. B: The liquid is cloudy but not separated into two or more layers. C: The liquid is cloudy and there is a small amount of precipitate (a small amount of phase separation has occurred).
D: When separated into two or more layers

<Hard segment content>
The hard segment content shown in Table 2 is a value (mass%) obtained by calculation using the formula "(mass of polyisocyanate compound+mass of chain extender)/(mass of polyisocyanate compound+mass of chain extender+mass of polyoxyalkylene diol)×100".

<NCO Unit Content>
The NCO unit content shown in Table 2 is a value (mass%) obtained by calculation using the formula "(mass of polyisocyanate compound)/(mass of polyisocyanate compound+mass of chain extender+mass of polyoxyalkylene diol)×100".

<Flow starting temperature>
The polyurethane resin obtained in each of the examples described below was dried at 80° C. for 2 hours. Thereafter, the flow initiation temperature was measured using a flow tester (product name: CFT-500EX, manufactured by Shimadzu Corporation) (a die with an aperture of 1 mm and a length of 1 mm was used, pressure was 2.9 MPa, and temperature rise rate was 3° C./min). The measurement results are shown in Table 2.

<Storage modulus and glass transition temperature>
The polyurethane resin films obtained in each of the examples described below were cut to a size of 5 mm x 10 mm to prepare test samples. The storage modulus E' (MPa) and glass transition temperature Tg (°C) of the obtained test samples were measured at -20°C, 0°C, and 25°C under the following conditions. The measurement results are shown in Table 2.
Measuring device: Dynamic viscoelasticity measuring device (product name: EXSTAR6000DMS6100, manufactured by Seiko Instruments Inc.)
Mode: Tensile mode Temperature range: -80 to 150°C
Heating rate: 3°C/min Measurement frequency: 1Hz
Distortion: 1%

<Tensile test>
The polyurethane resin films obtained in each of the examples described below were punched out using a dumbbell frame (dumbbell No. 3) to obtain test specimens. Using these test specimens, a tensile test (product name: Tensilon VTM, manufactured by Toyo Boardwin Co., Ltd.) was performed at a tensile speed of 300 mm/min to measure the tensile properties of the stress at 100% elongation (M100, unit: MPa), breaking strength (Tmax, unit: MPa), and breaking elongation (L, unit: %). The measurement results are shown in Table 2.
If the stress (M100) is in the range of 1.5 MPa or more, it can be said that the mechanical strength of the film is good.
If the breaking strength (Tmax) is in the range of 15 MPa or more, the toughness of the film can be said to be good.
If the breaking elongation (L) is in the range of 400% or more, the flexibility of the film can be said to be good.

<Hydrolysis resistance>
The dumbbell-shaped test pieces were immersed in 80° C. water for one week, and then subjected to a tensile test to measure the breaking strength. The breaking strength was compared with that before the hydrolysis resistance test, and the hydrolysis resistance was evaluated according to the retention rate according to the following criteria. The evaluation results are shown in Table 2.
<<Evaluation criteria>>
A: Retention rate 85% or more B: Retention rate less than 85% 60% or more C: Retention rate less than 60%

<Heat resistance (100℃)>
The dumbbell-shaped test pieces were stored in an oven at 100° C. for one week, and then subjected to a tensile test to measure the breaking strength. The breaking strength was compared with that before the heat resistance test, and the heat resistance (100° C.) was evaluated according to the retention rate according to the following criteria. The evaluation results are shown in Table 2.
<<Evaluation criteria>>
A: Retention rate 85% or more B: Retention rate less than 85% 60% or more C: Retention rate less than 60%

<Heat resistance (120℃)>
The dumbbell-shaped test pieces were stored in an oven at 120° C. for one week, and then subjected to a tensile test to measure the breaking strength. The breaking strength was compared with that before the heat resistance test, and the heat resistance (120° C.) was evaluated according to the retention rate according to the following criteria. The evaluation results are shown in Table 2.
<<Evaluation criteria>>
A: Retention rate 85% or more B: Retention rate less than 85% 60% or more C: Retention rate less than 60%

<Ethanol resistance>
The polyurethane resin film obtained in each of the examples described below was stored in ethanol at 23° C. for one week, then removed from the ethanol and weighed. The weight was compared with that before the ethanol resistance test, and the ethanol resistance was evaluated according to the swelling ratio according to the following criteria. The evaluation results are shown in Table 2.
<<Evaluation criteria>>
A: Swelling rate less than 25% B: Swelling rate less than 40% 25% or more C: Retention rate 40% or more

<Synthesis of polyoxyalkylene diol>
In the following synthesis examples, synthesis examples 1 to 9 are examples, and synthesis examples 10 to 13 are comparative examples.

(Synthesis Example 1)
A polycarbonate diol derived from two diol compounds, 1,9-nonanediol (1,9-ND) and 2-methyl-1,8-octanediol (MOD) (product name: C-1015N, manufactured by Kuraray Co., Ltd., transparent liquid, Mw/Mn=2.04, Mn=1050, composition ratio of 1,9-ND/MOD is 15/85 (molar ratio)) was used as an initiator.
Polyoxyalkylene diol (a1) was obtained by ring-opening addition polymerization of 100 parts by mass of propylene oxide (PO) as a cyclic ether at 130° C. using 0.02 parts by mass of zinc hexacyanocobaltate complex (TBA-DMC catalyst) having a ligand of t-butyl alcohol relative to 100 parts by mass of this initiator. The obtained polyoxyalkylene diol (a1) was a transparent liquid.

(Synthesis Example 2)
A polycarbonate diol derived from 1,6-hexanediol (1,6-HD) as a diol compound and ε-caprolactone (CL) as a cyclic ester (product name: UHC50-100, manufactured by Ube Industries, transparent liquid, Mw/Mn=2.07, Mn=1070, composition ratio of 1,6-HD/CL is 50/50 (molar ratio)) was used as an initiator.
Polyoxyalkylene diol (a2) was obtained by ring-opening addition polymerization of 100 parts by mass of this initiator and 100 parts by mass of PO as a cyclic ether at 130° C. in the same manner as in Synthesis Example 1. The obtained polyoxyalkylene diol (a2) was a transparent liquid.

(Synthesis Example 3)
Two types of diol compounds, 1,5-pentanediol (1,5-PD) and polycarbonate diol derived from 1,6-HD (product name: PH-50, manufactured by Ube Industries, transparent liquid, Mw/Mn=1.80, Mn=600, composition ratio of 1,5-BD/1,6-HD was 50/50 (molar ratio)) were used as initiators.
Polyoxyalkylene diol (a3) was obtained by ring-opening addition polymerization of 300 parts by mass of PO as a cyclic ether at 130° C. using 0.04 parts by mass of TBA-DMC catalyst as a ring-opening polymerization catalyst relative to 100 parts by mass of this initiator. The obtained polyoxyalkylene diol (a3) was a transparent liquid.

(Synthesis Example 4)
A polycarbonate diol derived from two diol compounds, 1,9-ND and MOD (product name: C-1015N, manufactured by Kuraray Co., Ltd., transparent liquid, Mw/Mn=2.04, Mn=1050, composition ratio of 1,9-ND/MOD was 15/85 (molar ratio)) was used as an initiator.
Polyoxyalkylene diol (a4) was obtained by ring-opening addition polymerization of 200 parts by mass of PO as a cyclic ether at 130° C. using 0.03 parts by mass of TBA-DMC catalyst as a ring-opening polymerization catalyst relative to 100 parts by mass of this initiator. The obtained polyoxyalkylene diol was a transparent liquid.

(Synthesis Example 5)
A polycarbonate diol derived from two diol compounds, 1,9-ND and MOD (product name: C-1015N, manufactured by Kuraray Co., Ltd., transparent liquid, Mw/Mn=2.04, Mn=1050, composition ratio of 1,9-ND/MOD was 15/85 (molar ratio)) was used as an initiator.
Polyoxyalkylene diol (a5) was obtained by ring-opening addition polymerization of 60 parts by mass of PO as a cyclic ether and 40 parts by mass of ethylene oxide (EO) at 130° C. using 0.02 parts by mass of TBA-DMC catalyst as a ring-opening polymerization catalyst relative to 100 parts by mass of this initiator. The obtained polyoxyalkylene diol (a5) was a transparent liquid.

(Synthesis Example 6)
A polycarbonate diol derived from two diol compounds, 1,5-PD and 1,6-HD (product name: PH-50, manufactured by Ube Industries, transparent liquid, Mw/Mn=1.80, Mn=600, composition ratio of 1,5-BD/1,6-HD was 50/50 (molar ratio)) was used as an initiator.
Polyoxyalkylene diol (a6) was obtained by ring-opening addition polymerization of 220 parts by mass of PO and 80 parts by mass of EO as cyclic ethers at 130° C. using 0.04 parts by mass of TBA-DMC catalyst as a ring-opening polymerization catalyst relative to 100 parts by mass of this initiator. The obtained polyoxyalkylene diol (a6) was a transparent liquid.

(Synthesis Example 7)
A polycarbonate diol derived from two diol compounds, 1,5-PD and 1,6-HD (product name: T5651, manufactured by Asahi Kasei Corporation, transparent liquid, Mw/Mn=2.11, Mn=1080, composition ratio of 1,5-PD/1,6-HD was 50/50 (molar ratio)) was used as an initiator.
Polyoxyalkylene diol (a7) was obtained by ring-opening addition polymerization of 700 parts by mass of PO as a cyclic ether at 130° C. using 0.08 parts by mass of TBA-DMC catalyst as a ring-opening polymerization catalyst relative to 100 parts by mass of this initiator. The obtained polyoxyalkylene diol (a7) was a transparent liquid.

(Synthesis Example 8)
A polycarbonate diol derived from two diol compounds, 1,4-butanediol (1,4-BD) and isosorbide (iSB) (product name: HS0840B, manufactured by Mitsubishi Chemical Corporation, transparent liquid, Mw/Mn=1.67, Mn=670, composition ratio of 1,4-BD/iSB was 60/40 (molar ratio)) was used as an initiator.
Polyoxyalkylene diol (a8) was obtained by ring-opening addition polymerization of 900 parts by mass of PO as a cyclic ether at 130° C. using 0.10 parts by mass of TBA-DMC catalyst as a ring-opening polymerization catalyst relative to 100 parts by mass of this initiator. The obtained polyoxyalkylene diol (a8) was a transparent liquid.

(Synthesis Example 9)
A polycarbonate diol derived from two diol compounds, 1,5-PD and 1,6-HD (product name: T5651, manufactured by Asahi Kasei Corporation, transparent liquid, Mw/Mn=2.11, Mn=1080, composition ratio of 1,5-PD/1,6-HD was 50/50 (molar ratio)) was used as an initiator.
Polyoxyalkylene diol (a9) was obtained by ring-opening addition polymerization of 300 parts by mass of PO as a cyclic ether at 130° C. using 0.04 parts by mass of TBA-DMC catalyst as a ring-opening polymerization catalyst relative to 100 parts by mass of this initiator. The obtained polyoxyalkylene diol (a9) was a cloudy white liquid, and precipitate was generated.

(Synthesis Example 10)
A polycarbonate diol derived from two diol compounds, 1,4-BD and 2,2-dimethyl-1,3-propanediol (neopentyl glycol) (NPG) (product name: NL1030B, manufactured by Mitsubishi Chemical Corporation, transparent liquid, Mw/Mn=1.71, Mn=980, composition ratio of 1,4-BD/NPG was 70/30 (molar ratio)) was used as an initiator.
Polyoxyalkylenediol (b1) was obtained by ring-opening addition polymerization of 100 parts by mass of PO as a cyclic ether to 100 parts by mass of this initiator in the same manner as in Synthesis Example 1. The obtained polyoxyalkylenediol (b1) was cloudy immediately after synthesis, and was phase-separated into two layers after standing for one week.

(Synthesis Example 11)
A polycarbonate diol derived from two diol compounds, 1,5-PD and 1,6-HD (product name: T5651, manufactured by Asahi Kasei Corporation, transparent liquid, Mw/Mn=2.11, Mn=1080, composition ratio of 1,5-PD/1,6-HD was 50/50 (molar ratio)) was used as an initiator.
Polyoxyalkylenediol (b2) was obtained by ring-opening addition polymerization of 100 parts by mass of PO as a cyclic ether to 100 parts by mass of this initiator in the same manner as in Synthesis Example 1. The obtained polyoxyalkylenediol (b2) was cloudy immediately after synthesis, and was phase-separated into two layers after standing for one week.

(Synthesis Example 12)
A polycarbonate diol derived from two diol compounds, 1,4-BD and iSB (product name: HS0840B, manufactured by Mitsubishi Chemical Corporation, transparent liquid, Mw/Mn=1.67, Mn=670, composition ratio of 1,4-BD/iSB was 60/40 (molar ratio)) was used as an initiator.
Polyoxyalkylenediol (b3) was obtained by ring-opening addition polymerization of 150 parts by mass of PO as a cyclic ether to 100 parts by mass of this initiator in the same manner as in Synthesis Example 1. The obtained polyoxyalkylenediol (b3) was cloudy immediately after synthesis, and was phase-separated into two layers after standing for one week.

(Synthesis Example 13)
A polycarbonate diol derived from two diol compounds, 1,5-PD and 1,6-HD (product name: T5651, manufactured by Asahi Kasei Corporation, transparent liquid, Mw/Mn=2.11, Mn=1080, composition ratio of 1,5-PD/1,6-HD was 50/50 (molar ratio)) was used as an initiator.
Polyoxyalkylenediol (b4) was obtained by ring-opening addition polymerization of 200 parts by mass of PO as a cyclic ether at 130° C. using 0.03 parts by mass of TBA-DMC catalyst as a ring-opening polymerization catalyst relative to 100 parts by mass of this initiator. The obtained polyoxyalkylenediol (b4) was cloudy immediately after synthesis, and was phase-separated into two layers after standing for one week.

For Synthesis Examples 1 to 13, the composition ratio (molar ratio) of polycarbonate diol (diol compound and cyclic ester), the content (mass%) of carbonate groups in polycarbonate diol (PCD) as an initiator, the amount (parts by mass) of propylene oxide (PO) as a cyclic ether per 100 parts by mass of polycarbonate diol (PCD), Mn and Mw/Mn of polyoxyalkylene diol (PCD + PO), the content (mass%) of carbonate groups in polyoxyalkylene diol (PCD + PO), the viscosity (mPa·s) of polyoxyalkylene diol (PCD + PO), and the evaluation results of phase separation are shown in Table 1.

As shown in Table 1, in Synthesis Examples 1, 2, 4, and 5, in which the content of carbonate groups in the polycarbonate diol is less than 30% by mass, no phase separation of the polyoxyalkylene diol (PCD + PO) was observed (Phase separation evaluation A). In addition, in Synthesis Examples 3, 6, and 7 to 9, in which the content of carbonate groups in the polycarbonate diol is 30% by mass or more and the content of carbonate groups in the polyoxyalkylene diol is 11% by mass or less, no phase separation of the polyoxyalkylene diol (PCD + PO) was observed (Phase separation evaluations A to C).
In contrast, in Synthesis Examples 10 to 13 in which the content of carbonate groups in the polycarbonate diol was 30% by mass or more and the content of carbonate groups in the polyoxyalkylene diol was more than 11% by mass, phase separation of the polyoxyalkylene diol (PCD+PO) was observed (phase separation evaluation D).
The Mn of the polyoxyalkylene diols (PCD+PO) obtained in Synthesis Examples 1 to 9 was 2,100 to 8,200.
The Mw/Mn of the polyoxyalkylene diols (PCD+PO) obtained in Synthesis Examples 1 to 9 was 1.10 to 1.60.
The polyoxyalkylene diols (PCD+PO) obtained in Synthesis Examples 1 to 9 had a viscosity of 880 to 6,600 mPa·s.

<Synthesis of polyurethane resin>
In the following examples, Examples 1 to 3 are working examples, and Example 4 is a comparative example.

(Example 1)
In a reaction vessel, 266 g of polyoxyalkylene diol (a1), 73.6 g of 4,4'-diphenylmethane diisocyanate (hereinafter sometimes referred to as "MDI") (isocyanate group index: 222), and 3.5 g of an antioxidant (Irganox 1010) were mixed, heated to 80°C, and reacted for 3 hours to obtain an isocyanate group-terminated precursor (polyurethane resin precursor).
Next, 15.1 g of 1,4-butanediol (1,4-BD) as a chain extender was added to the obtained isocyanate group-terminated precursor, and the obtained mixture was transferred to a stainless steel pallet and further reacted at 130° C. for 4 hours to obtain a polyurethane resin (A1) having a hard segment content of 25%.

The obtained polyurethane resin (A1) was dissolved in tetrahydrofuran and filtered using a hydrophilic polytetrafluoroethylene filter (product name: Millex-LH filter, manufactured by Merck Millipore, pore size: 0.45 μm, filter diameter: 25 mm), and Mn was measured by GPC.
The obtained polyurethane resin (A1) was molded at a temperature of 195° C. using a hydraulic molding machine to obtain a film having a thickness of about 250 μm.

(Example 2)
In a reaction vessel, 266 g of polyoxyalkylene diol (a2), 73.4 g of MDI (isocyanate group index: 226), and 3.5 g of an antioxidant (Irganox 1010) were mixed, heated to 80° C., and reacted for 3 hours to obtain an isocyanate group-terminated precursor (polyurethane resin precursor).
Next, 15.3 g of 1,4-BD was added as a chain extender to the obtained isocyanate group-terminated precursor, and the obtained mixture was transferred to a stainless steel pallet and further reacted at 130° C. for 4 hours to obtain a polyurethane resin (A2) having a hard segment content of 25%.

The Mn of the resulting polyurethane resin (A2) was measured in the same manner as in Example 1.
The polyurethane resin (A2) thus obtained was molded at 175° C. using a hydraulic molding machine to obtain a film having a thickness of about 250 μm.

(Example 3)
In a reaction vessel, 266 g of polyoxyalkylene diol (a3), 72.5 g of MDI (isocyanate group index: 248), and 3.5 g of an antioxidant (Irganox 1010) were mixed, heated to 80° C., and reacted for 3.5 hours to obtain an isocyanate group-terminated precursor (polyurethane resin precursor).
Next, 16.1 g of 1,4-BD was added as a chain extender to the obtained isocyanate group-terminated precursor, and the obtained mixture was transferred to a stainless steel pallet and further reacted at 130° C. for 4 hours to obtain a polyurethane resin (A3) having a hard segment content of 25%.

The Mn of the obtained polyurethane resin (A3) was measured in the same manner as in Example 1, but the obtained polyurethane resin was not dissolved in tetrahydrofuran, and the molecular weight could not be measured. Note that, since the polyurethane resin (A3) swelled when immersed in tetrahydrofuran, the molecular weight could not be measured, but it is presumed that the chain extension reaction had progressed and the molecular weight had increased.
The polyurethane resin (A3) thus obtained was molded at a temperature of 200° C. using a hydraulic molding machine to obtain a film having a thickness of about 250 μm.

(Example 4)
The polyoxyalkylene diol (b2) obtained in Synthesis Example 11 was allowed to stand at 23° C. for one week to maintain a two-phase separated state. In a reaction vessel, 200 g of the upper layer of this polyoxyalkylene diol (b2), 55.5 g of MDI (isocyanate group index: 193), and 2.7 g of an antioxidant (Irganox 1010) were mixed, heated to 80° C., and reacted for 3 hours to obtain an isocyanate group-terminated precursor.
Next, 6.6 g of 1,4-BD was added as a chain extender to the obtained isocyanate group-terminated precursor, and the obtained mixture was transferred to a stainless steel pallet and further reacted at 130° C. for 4 hours to obtain a polyurethane resin (B2) having a hard segment content of 25%.
The obtained polyurethane resin (B2) was dissolved in tetrahydrofuran and filtered using a hydrophilic polytetrafluoroethylene filter (product name: Millex-LH filter, manufactured by Merck Millipore, pore size: 0.45 μm, filter diameter: 25 mm), and Mn was measured by GPC.
The polyurethane resin (B2) thus obtained was molded at 125° C. using a hydraulic molding machine to obtain a film having a thickness of about 250 μm.

Hard segment content (mass%) of the polyurethane resin obtained in Examples 1 to 3
The hard segment content (mass%), NCO unit content (mass%), Mn, and flow initiation temperature (° C.), as well as the evaluation results of the storage modulus E' (MPa), glass transition temperature Tg (° C.), tensile properties (stress M100 (MPa), breaking strength Tmax (MPa), breaking elongation L (%)), hydrolysis resistance, heat resistance (100° C.), heat resistance (120° C.), and ethanol resistance of the obtained film are shown in Table 2. For Example 4, the hard segment content (mass%), NCO unit content (mass%), Mn, and flow initiation temperature (° C.) of the obtained polyurethane resin, as well as the evaluation results of the tensile properties (stress M100 (MPa), breaking strength Tmax (MPa), breaking elongation L (%)) of the obtained film are shown in Table 2.

As shown in Table 2, in Examples 1 to 3, good results were obtained in all of the items of storage modulus, glass transition temperature Tg, tensile properties, hydrolysis resistance, and heat resistance.
In contrast, in Example 4 using a polyoxyalkylene diol that undergoes phase separation, M100 and Tmax were small, and sufficient tensile properties were not obtained.
Moreover, compared to Examples 1 and 3, Example 2 exhibited good heat resistance (120° C.), and compared to Examples 2 and 3, Example 1 exhibited good ethanol resistance.
The Mn of the polyurethane resins obtained in Examples 1 and 2 was 73,000 to 97,000.
The flow initiation temperatures of the polyurethane resins obtained in Examples 1 to 3 were 145.0 to 180.0°C.
The storage modulus E' (-20°C) of the films obtained in Examples 1 to 3 was 13.0 to 18.0 MPa.
The storage modulus E' (0° C.) of the films obtained in Examples 1 to 3 was 7.0 to 10.0 MPa.
The storage modulus E' (25° C.) of the films obtained in Examples 1 to 3 was 6.0 to 8.0 MPa.
The glass transition temperatures Tg of the films obtained in Examples 1 to 3 were -32.0 to -30.0°C.
The stress M100 when the films obtained in Examples 1 to 3 were stretched 100% was 1.5 to 2.5 MPa.
The breaking strength Tmax of the films obtained in Examples 1 to 3 was 19.0 to 35.0 MPa.
The elongation at break L of the films obtained in Examples 1 to 3 was 690 to 970%.

The polyurethane resin obtained by the present invention can be suitably used in a wide range of fields, including adhesives, pressure sensitive adhesives, paints, coatings, synthetic leather, artificial leather, elastomers, elastic fibers, flooring materials, and printing ink binders.

Claims (13)

A method for producing a polyoxyalkylene diol by reacting a polycarbonate diol with a cyclic ether in the presence of a ring-opening polymerization catalyst, comprising the steps of:
The polycarbonate diol is at least one of a condensation polymer of two or more alcohols and a carbonate compound, and a reaction product of one or more alcohols and one or more cyclic esters with a carbonate compound,
A method for producing a polyoxyalkylene diol, which satisfies either the following (i) or the following (ii):
(i) The content of carbonate groups in the polycarbonate diol is less than 30 mass%.
(ii) The content of carbonate groups in the polycarbonate diol is 30% by mass or more, and the content of carbonate groups in the polyoxyalkylene diol is 11% by mass or less. The method for producing a polyoxyalkylene diol according to claim 1, wherein the content of carbonate groups in the polycarbonate diol is less than 30% by mass, and the content of carbonate groups in the polyoxyalkylene diol is 15% by mass or less. The method for producing a polyoxyalkylene diol according to claim 1, wherein the content of carbonate groups in the polycarbonate diol is 30% by mass or more, and the content of carbonate groups in the polyoxyalkylene diol is 10% by mass or less. The method for producing a polyoxyalkylene diol according to claim 3, wherein the content of carbonate groups in the polyoxyalkylene diol is 9% by mass or less. The method for producing a polyoxyalkylene diol according to any one of claims 1 to 4, wherein the number average molecular weight of the polycarbonate diol is 400 or more and 4,000 or less. The method for producing a polyoxyalkylene diol according to any one of claims 1 to 5, wherein the number average molecular weight of the polyoxyalkylene diol is 450 or more and 40,000 or less. A method for producing a polyurethane resin, comprising obtaining a polyoxyalkylene diol by the method for producing a polyoxyalkylene diol according to any one of claims 1 to 6, and reacting the obtained polyoxyalkylene diol with a polyisocyanate compound to produce a polyurethane resin. 8. The method for producing a polyurethane resin according to claim 7, comprising reacting the polyoxyalkylene diol with the polyisocyanate compound and further reacting with a chain extender to produce a polyurethane resin, wherein the chain extender is at least one selected from the group consisting of a polyol having at least two active hydrogens reactive with an isocyanate group and a polyamine having at least two active hydrogens reactive with an isocyanate group . The method for producing a polyurethane resin according to claim 8 , wherein the chain extender has a divalent hydrocarbon group having 2 to 12 carbon atoms, or a divalent hydrocarbon group having 2 to 12 carbon atoms containing an etheric oxygen atom between carbon atoms. A polyurethane resin obtained by the method for producing a polyurethane resin according to any one of claims 7 to 9 . 11. The polyurethane resin of claim 10 , wherein the polyurethane resin has a number average molecular weight of greater than 800. A polyurethane resin composition comprising the polyurethane resin according to claim 10 or 11 . An article comprising the polyurethane resin composition of claim 12 .