JP7819638B2 - Polycarbonate polyol, its production method and composition - Google Patents

Description

The present invention relates to polycarbonate polyols, their production methods, and compositions.

Like polyester polyols and polyether polyols, polycarbonate polyols are useful as raw materials for producing polyurethane resins by reacting them with polyisocyanate compounds, as well as for engineering plastics, adhesives, paints, etc., and are also used as modifiers for polyester resins, etc.

A known method for modifying polycarbonate diol is to react polycarbonate diol with lactone (for example, Patent Document 1). This product has fewer carbonate bonds than polycarbonate diol and contains ester bonds.

In order to modify the properties of polycarbonate, there is a known example in which urethane bonds are introduced by reacting a cyclic amide compound when synthesizing polycarbonate by reacting a polyol and a dialkyl carbonate (see, for example, Patent Document 2).

International Publication No. 2014/069563 US Patent Application Publication No. 2018/0251597

The polycarbonate diol of Patent Document 1 lacks solvent resistance when urethane-treated, and therefore further improvement in solvent resistance is required.
In addition, the polycarbonate of Patent Document 2 has a high viscosity and is difficult to handle due to its high molecular weight of 20,000 g/mol or more. Furthermore, Patent Document 2 does not clarify whether the polycarbonate has a molecular terminal structure, such as a hydroxyl group, that can react with isocyanate, and does not mention the derivation of polyurethane as a polycarbonate diol.

The object of the present invention is to provide a polycarbonate polyol that is easy to handle and improves the mechanical properties and solvent resistance of polyurethane resins obtained from polycarbonate diols.

Specific features of the present invention are as follows.

1. A polycarbonate polyol having an ester bond and a urethane bond and an acid value of 0.01 to 5.0 mgKOH/g.
2. The polycarbonate polyol according to 1 above, wherein the molar ratio of the urethane bond to the ester bond (urethane/ester) is 0.8 to 1.2.
3. The polycarbonate polyol according to 1 or 2 above, wherein the content of carbonate bonds is 3 to 35 mass% based on the total amount of the polycarbonate polyol.
4. The polycarbonate polyol according to any one of 1 to 3 above, wherein the content of ester bonds is 1.5 to 15 mass% based on the total amount of the polycarbonate polyol, and the content of urethane bonds is 2 to 20 mass% based on the total amount of the polycarbonate polyol.
5. The polycarbonate polyol according to any one of 1 to 4 above, wherein the content of ester bonds and urethane bonds represented by the following formula (I) is 10 to 90 mol %:
(E+U)/(E+U+C)×100 (I)
E: number of moles of ester bonds in the polycarbonate polyol, U: number of moles of urethane bonds in the polycarbonate polyol, C: number of moles of carbonate bonds in the polycarbonate polyol. 6. The polycarbonate polyol according to any one of 1 to 5 above, having a hydroxyl value of 25 to 250 mgKOH/g.
7. The polycarbonate polyol according to any one of 1 to 6 above, which has a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2):

(In the formula, ^R1 and ^R2 represent hydrocarbon groups having 2 to 20 carbon atoms.)

8. The polycarbonate polyol according to 7 above, wherein in formula (1), R ¹ is a linear or branched alkylene group having 4 to 7 carbon atoms.
9. The polycarbonate polyol according to any one of 1 to 8 above, having a number average molecular weight of 400 to 4,500 g/mol.
10. The polycarbonate polyol according to any one of 1 to 9 above, which is liquid at room temperature (25°C).
11. A method for producing a polycarbonate polyol having an ester bond and a urethane bond and an acid value of 0.01 to 5.0 mgKOH/g, comprising:
A method for producing a polycarbonate polyol using a transesterification catalyst, at least one carbonate represented by the following formula (3), at least one diol represented by the following formula (4), and a cyclic amide represented by the following formula (5):

(In the formula, ^R1 and ^R2 represent a hydrocarbon group having 2 to 20 carbon atoms. In the formula, ^R3 represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 5 to 8 carbon atoms, and two ^R3s in the same molecule may be the same or different, or two ^R3s may be joined together to form a ring as an alkylene group having 1 to 4 carbon atoms.)

12. The method for producing a polycarbonate polyol according to 11 above, wherein the transesterification catalyst is a titanium compound and/or an alkali metal compound.
13. A polyurethane resin-forming composition comprising the polycarbonate polyol (A) according to any one of claims 1 to 10 and a polyisocyanate (C).
14. A polyurethane resin having a structure derived from the polycarbonate polyol (A) described in any one of items 1 to 10 above and a structure derived from the polyisocyanate (C).
15. An aqueous polyurethane resin dispersion comprising the polyurethane resin according to 14 above.
16. A coating composition comprising the polyurethane resin according to 14 above.
17. A coating composition comprising the polyurethane resin according to 14 above.
18. An adhesive composition comprising the polyurethane resin of claim 14.
19. A polyurethane resin film comprising the polyurethane resin according to 14 above.
20. Synthetic leather containing the polyurethane resin described in 14 above.
21. A thermoplastic polyurethane comprising the polyurethane resin described in 14 above.
22. A thermoset cast polyurethane comprising the polyurethane resin described in 14 above.

The present invention provides a polycarbonate polyol that is easy to handle and improves the mechanical properties and solvent resistance of polyurethane resins obtained from the polycarbonate polyol.

[Polycarbonate polyol]
The polycarbonate polyol of the present invention has an ester bond and a urethane bond and an acid value of 0.01 to 5.0 mgKOH/g. This makes it possible to provide a polycarbonate polyol that is easy to handle and improves the mechanical properties and solvent resistance of polyurethane resins obtained from the polycarbonate polyol. The polycarbonate polyol of the present invention is preferably a polycarbonate diol having hydroxyl groups at both molecular terminals.
In the present invention, "easy to handle" means that at least one of the following conditions 1) and 2) is satisfied.
1) The viscosity at 75°C is 3000 cP or less. 2) The viscosity is liquid at room temperature (25°C).
The ease of handling makes it possible to easily use the polycarbonate polyol as a raw material for polyurethane resins and the like.

<Ester bond>
The content of ester bonds is preferably 1.5% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, and even more preferably 8% by mass or more, based on the total amount of polycarbonate polyol. Furthermore, the content of ester bonds is preferably 15% by mass or less, more preferably 14% by mass or less, and even more preferably 12% by mass or less, based on the total amount of polycarbonate polyol. The content of ester bonds is preferably 1.5 to 15% by mass, more preferably 3 to 14% by mass, and even more preferably 5 to 12% by mass, based on the total amount of polycarbonate polyol. By adjusting the content within this range, a polycarbonate polyol can be obtained that is easy to handle and improves the mechanical properties and chemical resistance of the polyurethane resin.

<Urethane bond>
The content of urethane bonds is preferably 2% by mass or more, more preferably 4% by mass or more, even more preferably 9% by mass or more, and even more preferably 13% by mass or more, based on the total amount of polycarbonate polyol. Furthermore, the content of urethane bonds is preferably 20% by mass or less, more preferably 19% by mass or less, and even more preferably 16% by mass or less, based on the total amount of polycarbonate polyol. The content of urethane bonds is preferably 2 to 20% by mass, more preferably 4 to 19% by mass, and even more preferably 9 to 16% by mass, based on the total amount of polycarbonate polyol. By adjusting the content within this range, a polycarbonate polyol can be obtained that is easy to handle and improves the mechanical properties and chemical resistance of the polyurethane resin.

<Carbonate bond>
The carbonate bond content is preferably 3% by mass or more, more preferably 6% by mass or more, even more preferably 11% by mass or more, and even more preferably 14% by mass or more, based on the total amount of polycarbonate polyol. Furthermore, the carbonate bond content is preferably 35% by mass or less, more preferably 32% by mass or less, and even more preferably 23% by mass or less, based on the total amount of polycarbonate polyol. The carbonate bond content is preferably 3 to 35% by mass, more preferably 6 to 32% by mass, and even more preferably 11 to 23% by mass, based on the total amount of polycarbonate polyol. By adjusting the content within this range, a polycarbonate polyol can be obtained that is easy to handle and improves the mechanical properties and chemical resistance of the polyurethane resin. The polycarbonate polyol of the present invention is particularly preferably one that has ester bonds, urethane bonds, and carbonate bonds, and the contents of each bond are all within the above-mentioned ranges, since this allows the polycarbonate polyol to fully exhibit the general properties of polycarbonate and further has excellent chemical resistance and handleability.

<Ratio of each bond>
The molar ratio of the urethane bond to the ester bond (urethane/ester) is preferably 0.8 to 1.2, more preferably 0.9 to 1.1, and even more preferably 0.95 to 1.05. By adjusting the ratio to within this range, it is possible to obtain a polycarbonate polyol that is easy to handle and that improves the mechanical properties and solvent resistance of the polyurethane resin.
Furthermore, the content of ester bonds and urethane bonds represented by the following formula (I) is preferably 10 to 90 mol %. By setting it within this range, it is possible to obtain a polycarbonate polyol that is easy to handle and that improves the mechanical properties and solvent resistance of the polyurethane resin.

(E+U)/(E+U+C)×100 (I)
E: number of moles of ester bonds in polycarbonate polyol U: number of moles of urethane bonds in polycarbonate polyol C: number of moles of carbonate bonds in polycarbonate polyol

<Measurement of the Content of Ester Bonds, Urethane Bonds, and Carbonate Bonds>
It is also possible to measure ¹ H NMR of the polycarbonate polyol and quantify the contents of ester bonds, urethane bonds, and carbonate bonds contained in the polycarbonate polyol from the integrated values.
The contents of ester bonds, urethane bonds, and carbonate bonds contained in the polycarbonate polyol can also be calculated from the amounts of raw materials charged for the polycarbonate polyol.

<Acid value>
The polycarbonate polyol of the present invention has an acid value of 0.01 to 5.0 mgKOH/g. Within this range, a polyurethane resin with particularly good physical properties can be obtained using this as a raw material. The acid value is preferably 0.01 to 1.0 mgKOH/g, and more preferably 0.01 to 0.5 mgKOH/g. By adjusting the acid value within this range, a polycarbonate polyol can be obtained that is easy to handle and improves the mechanical properties and solvent resistance of the polyurethane resin.
In this specification, the acid value is a value measured in accordance with the indicator titration method of JIS K 1557.

<Hydroxyl value>
The polycarbonate polyol of the present invention may have a hydroxyl value of 25 to 250 mgKOH/g. If the hydroxyl value is within this range, a polyurethane resin with particularly good physical properties can be obtained using this as a raw material.

<Repeating unit>
The polycarbonate polyol preferably has a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2).

In the formula, R ¹ and R ² represent divalent hydrocarbon groups having 2 to 20 carbon atoms.
^R1 is preferably a linear, branched, or cyclic aliphatic hydrocarbon group having 4 to 8 carbon atoms or an aromatic hydrocarbon group having 8 to 12 carbon atoms, more preferably a linear, branched, or cyclic alkylene group having 4 to 8 carbon atoms, even more preferably a linear or branched alkylene group having 4 to 7 carbon atoms, and even more preferably a linear alkylene group having 5 or 6 carbon atoms.
^R2 is preferably an aliphatic or aromatic hydrocarbon group having 5 to 12 carbon atoms, more preferably a linear or branched alkylene group having 6 to 12 carbon atoms, and even more preferably a linear alkylene group having 6 carbon atoms.
^R1 and ^R2 may be a plurality of types of the hydrocarbon groups. For example, the polycarbonate polyol may have a repeating unit in which ^R1 is an alkylene group having 5 carbon atoms and a repeating unit in which ^R1 is an alkylene group having 6 carbon atoms.
By making R ¹ and R ² the divalent hydrocarbon group, it is possible to obtain a polycarbonate polyol that is easy to handle and improves the mechanical properties and solvent resistance of the polyurethane resin.

The hydrocarbon group may be a linear or branched alkylene group having 2 to 20 carbon atoms, such as an ethylene group, trimethylene group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, propylene group, isobutylene group, 2-methyltetramethylene group, 2-methylpentamethylene group, 3-methylpentamethylene group, isononamethylene group, or 2-methylnonamethylene group; or a substituted or unsubstituted cycloalkylene group having 3 to 20 carbon atoms, such as a cyclopentylene group, cyclohexylene group, or 1,2-dimethylenecycloalkylene group. Examples of repeating units include a pentane group, a 1,3-dimethylenecyclopentane group, a 1,2-dimethylenecyclohexane group, a 1,3-dimethylenecyclohexane group, a 1,4-dimethylenecyclohexane group, a 4,4'-methylenedicyclohexylene group, a 2,2-dicyclohexylenepropane group, and the like; and a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, for example, a phenylene group, a 1,2-dimethylenebenzene group, a 1,3-dimethylenebenzene group, a 1,4-dimethylenebenzene group, a naphthylene group, a 4,4'-methylenediphenylene group, a 2,2-diphenylenepropane group, and the like.

<Average molecular weight>
In the polycarbonate polyol of the present invention, the number average molecular weight Mn is preferably 400 to 4500 g/mol. Within this range, fluidity (e.g., viscosity of 500 to 10,000 cP) can be easily achieved at elevated temperatures (e.g., 75°C), resulting in excellent handleability. The number average molecular weight Mn is more preferably 500 to 3,500 g/mol, and even more preferably 500 to 3,000. In this specification, the number average molecular weight Mn refers to the number average molecular weight calculated based on the hydroxyl value measured in accordance with JIS K 1577. Specifically, the hydroxyl value is measured and calculated using the terminal group determination method using the formula (56.1 x 1000 x valence) / hydroxyl value (in this formula, the unit of hydroxyl value is [mg KOH/g]). In the formula, valence is the number of hydroxyl groups per molecule.

In the polycarbonate polyol of the present invention, the weight average molecular weight Mw is preferably 500 to 30,000 g/mol. The weight average molecular weight Mw is more preferably 1,000 to 13,000 g/mol. In this specification, the weight average molecular weight Mw is a value measured by GPC.

In the polycarbonate polyol of the present invention, the dispersity Mw/Mn is preferably 1.0 to 3.0. The dispersity Mw/Mn is preferably 2.0 to 2.3. If the dispersity is greater than 3.0, the variation in the sizes of the hard segments and soft segments in the resulting polyurethane will be greater, which may result in reduced mechanical properties of the polyurethane.

<Physical properties>
The polycarbonate polyol of the present invention preferably has a water content of 1 to 10,000 ppm. If the water content is more than 10,000 ppm, the amount of urea groups produced as by-products by the reaction of water with isocyanate during polyurethane synthesis increases, which may impair the flexibility of the polyurethane.
The glass transition point of the polycarbonate polyol of the present invention is preferably −80° C. to +50° C. If the glass transition point is lower than −80° C., the strength of the resulting polyurethane will be insufficient, and if it is higher than 50° C., it may become brittle around room temperature.
The viscosity of the polycarbonate polyol of the present invention is preferably 10 to 90,000 cP (75° C.), more preferably 50 to 10,000 cP (75° C.), and even more preferably 100 to 3,000 cP (75° C.). If the viscosity is higher than 3,000 cP (75° C.), handling properties may deteriorate during polyurethane synthesis.

Changing the raw diol or modifying synthetic polycarbonate polyols is known as a way to improve the properties of polycarbonate polyols. Using a diol compound with a low carbon number as a raw material for polycarbonate polyol increases the concentration of carbonate bonds in the polycarbonate polyol, and the high cohesive strength of the carbonate bonds improves the solvent resistance of the polyurethane. On the other hand, polycarbonate polyols composed of a structure derived from a diol with a low carbon number and carbonate bonds are known to have high viscosity. The present invention solves this problem by using a polycarbonate polyol that has ester bonds and urethane bonds and a certain acid value.

[Manufacturing method]
The production method of the present invention is a method for producing a polycarbonate polyol having ester bonds and urethane bonds and having an acid value of 0.01 to 5.0 mgKOH/g, which method uses a transesterification catalyst, at least one carbonate represented by the following formula (3), at least one diol represented by the following formula (4), and a cyclic amide represented by the following formula (5).
The method for producing a polycarbonate polyol is preferably a method for producing a polycarbonate polyol by reacting at least one carbonate represented by the following formula (3) with at least one diol represented by the following formula (4) in the presence of a transesterification catalyst, and then reacting the resulting product with a cyclic amide represented by the following formula (5). Alternatively, the method for producing a polycarbonate polyol is preferably a method for producing a polycarbonate polyol by simultaneously reacting the carbonate represented by (3), at least one diol represented by the following formula (4), and the cyclic amide represented by the following formula (5).

In the formula, R ¹ and R ² have the same meanings as defined above.
In the formula, ^R3 represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 5 to 8 carbon atoms, and two ^R3 in the same molecule may be the same or different, or two ^R3 may be joined together to form a ring as an alkylene group having 1 to 4 carbon atoms. ^R3 is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably an alkyl group having 1 or 2 carbon atoms.

<Diol>
Examples of the diol include linear alkane diols having 2 to 20 carbon atoms, such as 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol.
Further examples include branched alkane diols having 2 to 20 carbon atoms such as 2-methyl-1,8-octanediol, 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, 2-butyl-2-ethyl-1,3-propanediol, and 2,2-dimethyl-1,3-propanediol; and 1,4-cyclohexanedimethanol. diols having an alicyclic structure having 6 to 20 carbon atoms, such as 1,3-cyclohexanedimethanol, 1,4-cyclohexanediol, 1,4-bis(hydroxyethyl)cyclohexane, 2,2-bis(4-hydroxycyclohexyl)propane, and 2,7-norbornanediol; and diols having an aromatic cyclic structure having 6 to 20 carbon atoms, such as 1,4-benzenedimethanol, 1,3-benzenedimethanol, 1,2-benzenedimethanol, and 2,7-naphthalenedimethanol.

<Carbonate>
Examples of carbonates (hereinafter also referred to as carbonate esters) include aliphatic carbonate esters such as dimethyl carbonate and diethyl carbonate; aromatic carbonate esters such as diphenyl carbonate; and cyclic carbonate esters such as ethylene carbonate. From the viewpoint of ease of removing unnecessary by-products, aliphatic carbonate esters or cyclic carbonate esters are preferred, and dimethyl carbonate or ethylene carbonate is particularly preferred.

<Cyclic Amide>
Examples of the cyclic amide include aliphatic cyclic amides having 5 to 12 carbon atoms; cyclic amides such as 2-pyrrolidone, piperidone, N-methylpyrrolidone, ε-caprolactam, N-methylcaprolactam, and laurolactam, with ε-caprolactam being preferred.

In addition, instead of the cyclic amide, a compound containing 5 to 12 aliphatic or aromatic hydrocarbon groups, an amino group, and a carboxyl group in the same molecule can also be used.

<Catalyst>
A catalyst can be used when producing the polycarbonate polyol of the present invention. The catalyst can be one that is commonly used as a transesterification catalyst. Examples of the transesterification catalyst include alkali metal compounds, alkaline earth metal compounds, aluminum compounds, zinc compounds, manganese compounds, nickel compounds, antimony compounds, zirconium compounds, titanium compounds, and organotin compounds, with titanium compounds and/or alkali metal compounds being more preferred. These catalysts may be used in combination.

Examples of alkali metal compounds include alkali metal hydroxides (lithium hydroxide, sodium hydroxide, potassium hydroxide, etc.), alkali metal carbonates (lithium carbonate, sodium carbonate, potassium carbonate, etc.), alkali metal carboxylates (lithium acetate, sodium acetate, potassium acetate, etc.), alkali metal alkoxides (lithium methoxide, sodium methoxide, potassium t-butoxide, etc.), etc. Examples of alkaline earth metal compounds include alkaline earth metal hydroxides (magnesium hydroxide, etc.), alkaline earth metal alkoxides (magnesium methoxide, etc.), etc.

Examples of the aluminum compound include aluminum alkoxides (aluminum ethoxide, aluminum isopropoxide, aluminum sec-butoxide, etc.), aluminum acetylacetonate, and the like.
Examples of zinc compounds include zinc carboxylates (such as zinc acetate), zinc acetylacetonate, and the like.
Examples of the manganese compound include manganese carboxylates (such as manganese acetate), manganese acetylacetonate, and the like.
Examples of nickel compounds include nickel carboxylates (such as nickel acetate), nickel acetylacetonate, and the like.
Examples of antimony compounds include antimony carboxylates (antimony acetate, etc.), antimony alkoxides, and the like.
Examples of the zirconium compound include zirconium alkoxides (zirconium propoxide, zirconium butoxide, etc.), zirconium acetylacetonate, etc.

Examples of titanium compounds include titanium alkoxides (titanium tetraethoxide, titanium tetrapropoxide, titanium tetrabutoxide, tetracyclohexyl titanate, tetrabenzyl titanate, etc.), titanium acylates (tributoxytitanium stearate, isopropoxystearate, etc.), and titanium chelates (diisopropoxytitanium bisacetylacetonate, dihydroxy bislactatotitanium, etc.).
Examples of the organotin compound include dibutyltin oxide, dibutyltin diacetate, and dibutyltin dilaurate.
Each carboxylate preferably has 2 to 30 carbon atoms, more preferably 2 to 18 carbon atoms, and each alkoxide preferably has an alkoxy group having 1 to 30 carbon atoms, more preferably 2 to 18 carbon atoms.
Among the above catalysts, titanium compounds, organotin compounds, and alkali metal compounds are preferred, titanium compounds and/or alkali metal compounds are more preferred, and titanium alkoxides, alkali metal hydroxides and/or alkali metal carbonates are even more preferred. These catalysts may be used in combination.
Among the titanium alkoxides, titanium tetraalkoxides such as titanium tetraethoxide, titanium tetrapropoxide, and titanium tetrabutoxide are more preferred, with titanium tetrabutoxide being even more preferred.
The above diols, carbonates, cyclic amides, and catalysts may be used singly or in combination of two or more.

<Method>
The following method can be used to produce the polycarbonate polyol of the present invention.
1. There is a production method in which a diol compound represented by formula (4), a cyclic amide represented by formula (5), and a carbonate represented by formula (3) are all mixed together and subjected to a transesterification reaction while removing alcohol and the like.
2. There is a method in which a diol compound represented by formula (4) and a carbonate represented by formula (3) are subjected to a transesterification reaction, and then a cyclic amide represented by formula (5) and, if necessary, a diol compound represented by formula (4) are added and reacted.
3. There is a method in which a cyclic amide represented by formula (5) and a diol compound represented by formula (4) are polymerized, and then a diol compound represented by formula (4) and a carbonate represented by formula (3) are added and reacted.
Among these, the method shown in 2 above is preferred from the viewpoint that a variety of products can be synthesized by changing the amount of the cyclic amide represented by formula (5) added using one type of polycarbonate polyol obtained by transesterification of the diol compound represented by formula (4) with the carbonate represented by formula (3) as a common raw material.

The method for producing the polycarbonate polyol described above in 2 will now be explained. This production method comprises two reaction stages.
First step: A diol compound represented by formula (4) is subjected to a transesterification reaction with a carbonate represented by formula (3).
Second step: To the resulting reaction mixture, a cyclic amide represented by formula (5) and, if necessary, a diol compound represented by formula (4) are added and reacted.

(First stage reaction)
The diol compound represented by formula (4) and the carbonate represented by formula (3) are subjected to a transesterification reaction, preferably in the presence of a catalyst, while distilling off alcohol derived from the carbonate.
The reaction temperature varies depending on the type of diol compound and carbonate ester used, but is preferably 90 to 230°C.
The pressure in the reaction system is not particularly limited, but is preferably reduced to 30 to 500 mmHg. The reaction can be carried out in an atmosphere or stream of air, carbon dioxide, or an inert gas (nitrogen, argon, helium, etc.), but is preferably carried out in an inert gas atmosphere or stream.
When a catalyst is added, the amount of the catalyst added is preferably 1 to 20,000 ppm relative to the total amount of the feed.

(Second stage reaction)
The polycarbonate polyol of the present invention can be obtained by adding the cyclic amide represented by formula (5) and, if necessary, the diol compound represented by formula (4) to the product (polycarbonate polyol) obtained above, and reacting them while distilling off by-products such as alcohol, if necessary.
The reaction temperature is preferably set so that the cyclic amide represented by formula (5) is not substantially distilled off, and more preferably from 90 to 230°C.
The pressure in the reaction system for this reaction is not particularly limited, but is preferably reduced to 30 to 500 mmHg. The reaction can be carried out in an atmosphere or stream of air, carbon dioxide, or an inert gas (nitrogen, argon, helium, etc.), but is preferably carried out in an inert gas atmosphere or stream.

The catalyst may be a new catalyst, or the catalyst used in the first-stage reaction may be used as is. In place of the cyclic amide, a compound containing 5 to 12 aliphatic or aromatic hydrocarbon groups, an amino group, and a carboxyl group in the same molecule may also be used.

[Polyurethane resin-forming composition]
The polycarbonate polyol (A) is used as a raw material in forming a polyurethane resin, and can be blended in a polyurethane resin-forming composition. The polyurethane resin-forming composition of the present invention contains the polycarbonate polyol (A) and the polyisocyanate (C), and preferably contains the polycarbonate polyol (A), the polyol (B) (excluding the polycarbonate polyol (A)), and the polyisocyanate (C).
The polyurethane resin-forming composition is classified into one-component type and two-component type.
The one-component type contains the polycarbonate polyol (A) of the present invention, a polyol (B), and a polyisocyanate (C).
In the polyurethane resin-forming composition, the proportion of the polycarbonate polyol (A) relative to the total amount of the polycarbonate polyol (A) and the polyol (B) is preferably more than 0 and 95% by mass, more preferably 1 to 90% by mass, and even more preferably 2 to 85% by mass, from the viewpoint of mechanical performance after urethanization.
The two-component type comprises a first component containing the polycarbonate polyol (A) and the polyol (B) and a second component containing the polyisocyanate (C), and is sold, for example, as a kit consisting of the first component and the second component.

Here, polyol (B) is a polyol other than the polycarbonate polyol (A). For example, high-molecular-weight polyols and low-molecular-weight polyols can be used as polyol (B). For ease of production, it is preferable to use high-molecular-weight diols and low-molecular-weight diols.

While there are no particular restrictions on the high molecular weight diol, it is preferable for the number average molecular weight to be 400 to 8,000 g/mol. A number average molecular weight within this range makes it easy to achieve appropriate viscosity and good handleability. It is easy to ensure the performance of the soft segment, and when a coating film is formed using a composition containing the resulting polyurethane resin, cracking is easily suppressed. Furthermore, sufficient reactivity with polyisocyanate (C) allows for efficient production of the polyurethane resin. It is more preferable for the number average molecular weight of polyol (B) to be 400 to 4,000 g/mol. The number average molecular weight is a value measured using the method described in the examples.

Examples of high molecular weight diols include polycarbonate polyols other than the polycarbonate polyol (A), polyester polyols, polyether polyols, etc. In terms of the light resistance, weather resistance, heat resistance, hydrolysis resistance, and oil resistance of the resulting polyurethane resin-containing composition and the coating film obtained therefrom, polycarbonate polyols other than the polycarbonate polyol (A) are preferred.
Examples of low molecular weight diols include the same diols as those represented by the formula (4), and 1,3-propanediol, 1,4-butanediol, and 1,5-pentanediol are preferred.

The polyisocyanate (C) is not particularly limited, but examples include aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, etc.

Specific examples of aromatic polyisocyanates include 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate (TDI), 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 2,4-diphenylmethane diisocyanate, 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, 4,4',4''-triphenylmethane triisocyanate, m-isocyanatophenylsulfonyl isocyanate, and p-isocyanatophenylsulfonyl isocyanate.

Specific examples of aliphatic polyisocyanates include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethyl caproate, bis(2-isocyanatoethyl) fumarate, bis(2-isocyanatoethyl) carbonate, and 2-isocyanatoethyl-2,6-diisocyanatohexanoate.

Specific examples of alicyclic polyisocyanates include isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), bis(2-isocyanatoethyl)-4-dicyclohexene-1,2-dicarboxylate, 2,5-norbornane diisocyanate, and 2,6-norbornane diisocyanate.

Polyisocyanates typically have two isocyanate groups per molecule, but polyisocyanates with three or more isocyanate groups, such as triphenylmethane triisocyanate or isocyanurate derivatives, can also be used as long as the polyurethane resin in this invention does not gel.

Polyisocyanates may be used singly or in combination of two or more. Depending on the purpose, the polyurethane resin-forming composition may contain blocking agents, wetting agents, heat stabilizers, light stabilizers, plasticizers, inorganic fillers, lubricants, colorants, silicone oil, foaming agents, flame retardants, and the like.

<Polyurethane resin>
The polyurethane resin-forming composition of the present invention contains a polycarbonate polyol (A) and a polyisocyanate (C), and preferably contains a polycarbonate polyol (A), a polyol (B) (excluding the polycarbonate polyol (A)), and a polyisocyanate (C).
A polyurethane resin is obtained by reacting at least the polycarbonate polyol (A) and the polyisocyanate (C). Therefore, the polyurethane resin of the present invention has a structure derived from the polycarbonate polyol (A) and a structure derived from the polyisocyanate (C), and preferably has a structure derived from the polycarbonate polyol (A), a structure derived from the polyol (B) (excluding the polycarbonate polyol (A)), and a structure derived from the polyisocyanate (C).
A catalyst can also be used during the reaction. The catalyst is not particularly limited, but examples include salts of metals with organic or inorganic acids, such as tin-based catalysts (trimethyltin laurate, dibutyltin dilaurate, etc.) and lead-based catalysts (lead octoate, etc.), as well as organometallic derivatives, amine-based catalysts (triethylamine, N-ethylmorpholine, triethylenediamine, etc.), and diazabicycloundecene-based catalysts. Among these, dibutyltin dilaurate and dioctyltin dilaurate are preferred from the viewpoint of reactivity.

The reaction temperature during the reaction is not particularly limited, but is preferably 40 to 120°C, and more preferably 60 to 100°C.

[Application]
By using the polyurethane resin-forming composition, it is possible to obtain an aqueous polyurethane resin dispersion, a paint composition, a coating composition, a polyurethane resin film, an adhesive composition, synthetic leather, a thermoplastic polyurethane (TPU), or a thermoset/cast polyurethane (TSU) by a known method. That is, the aqueous polyurethane resin dispersion, the paint composition, the coating composition, the ink composition, the polyurethane resin film, the adhesive composition, synthetic leather, a thermoplastic polyurethane (TPU), or a thermoset/cast polyurethane (TSU) contains the polyurethane resin.

The present invention will be explained in more detail below with reference to examples and comparative examples. However, the present invention is not limited to the following examples. Note that room temperature is 25°C.

<Measurement method>
[Acid value]
A 10 g sample was dissolved in a 50/50 (mass ratio) toluene/ethanol solution and titrated with 0.1 N KOH ethanol solution. The acid value was calculated using the following formula: 5.61 × (C − B ¹ ) × f/s, where B ¹ is the amount (mL) of 0.1 N KOH ethanol standard solution required to neutralize the blank, C is the amount (mL) of 0.1 N KOH ethanol standard solution required to neutralize the sample, f is the factor of the 0.1 N KOH ethanol standard solution, and s is the mass (g) of the sample.

[Content of ester bond, urethane bond and carbonate bond]
The contents of ester bonds, urethane bonds, and carbonate bonds contained in the polycarbonate polyol were calculated from the amounts of raw materials charged for the polycarbonate polyol.

[Viscosity of Polycarbonate Polyol]
The viscosity was measured using an LVDV II + Pro cone and Brookfield plate viscometer with a spindle cone model CPE-41 at 75°C.
(Properties at room temperature)
The properties of polycarbonate polyol at room temperature are determined by visually inspecting a sample that has been heated at 80° C. for 3 hours and then left to stand at 25° C. for 24 hours. A sample that is not visible solid and not cloudy is considered to be transparent.
Whether or not the polycarbonate polyol is in a liquid state is determined by checking whether or not it is transparent and fluid when heated at 80°C for 3 hours and then left at 25°C for 24 hours.

[Polyurethane molecular weight]
The molecular weights (number average molecular weight and weight average molecular weight) in terms of polystyrene were measured by GPC under the following conditions.
Column: TSKgel HZ1000 + Hz3000 (Tosoh) (40°C)
Mobile phase: THF, flow rate 0.6ml/min
Detector: RI (40°C)

[Hydroxyl value]
It was determined by titration in accordance with JIS K 1557. Here, the unit of the hydroxyl value is mgKOH/g.

[Elastic modulus, stress at break and elongation at break]
The test was carried out in an environment of 23°C and 50% humidity in accordance with ISO 527. Specifically, the elastic modulus, tensile strength, and elongation at break of a polyurethane resin film specimen having a thickness of 0.05 to 0.10 mm were measured at a width of 5 mm, a test length of 20 mm, and a test speed of 100 mm/min.

[Chemical resistance test]
The cotton soaked in the chemicals was placed on the polyurethane resin film obtained in each Example and Comparative Example, and the film was covered with a lid and left to stand at room temperature. After 24 hours, the polyurethane resin film was visually inspected for any changes and evaluated according to the following criteria.
Excellent: No change Good: The polyurethane resin film turns slightly white Fair: The polyurethane resin film turns obviously white Poor: The polyurethane resin film turns white and peels off

[Swelling test, dissolution resistance test]
The polyurethane resin film whose initial mass had been measured was immersed in the solvent at 25° C. for 10 minutes, and after being taken out, the solvent was quickly wiped off and the mass after immersion was measured. The swelling ratio was evaluated by the following formula.
Swelling rate = 100 x (mass after immersion - initial mass) / initial mass (%)
The closer the swelling ratio is to 0%, the better the solvent resistance is.

[Pendulum hardness]
Measurement was carried out using the Persoz pendulum method according to ISO 1522.

In the examples, the abbreviations indicate the following compounds, etc.
TBT: tetrabutoxytitanium KOH: potassium hydroxide NaOH: sodium hydroxide K ₂ CO ₃ : potassium carbonate LiOH: lithium hydroxide

(Example 1: Synthesis of polycarbonate polyol (1))
170 g (hydroxyl value: 57.6 mgKOH/g) of polycarbonate diol (ETERNACOLL (registered trademark) UH-200N, manufactured by Ube Industries, Ltd.), 6.07 g of 1,6-hexanediol (manufactured by Ube Industries, Ltd.), 94.02 g of ε-caprolactam (manufactured by Ube Industries, Ltd.), and 0.4991 g of tetrabutoxytitanium (manufactured by TCI) as a catalyst were mixed and reacted under normal pressure at 190°C for 8 hours to obtain polycarbonate polyol (1) that was solid at room temperature.
The fact that the target compound was obtained was confirmed by NMR, where the peaks of the raw material ε-caprolactam disappeared and new peaks derived from ester bonds and urethane bonds appeared.
The resulting polycarbonate polyol (1) had a hydroxyl value of 64.5 mg KOH/g and an acid value of 0.17 mg KOH/g.

(Examples 2 to 11: Synthesis of polycarbonate polyol)
A polycarbonate polyol that was solid at room temperature was obtained by carrying out the reaction in the same manner as in Example 1, except that the mass of the raw materials, the type and amount of the catalyst, and the reaction temperature and time were changed as shown in Table 1. The polycarbonate polyol obtained in Example 11 was a liquid at room temperature .

Example 12: Synthesis of one-component polyurethane resin and film thereof
30.0 g of the polycarbonate polyol (1) synthesized in Example 1, 2.89 g of 1,4-butanediol (manufactured by Merck), 108.45 g of dimethylformamide (manufactured by Merck), 0.023 g (500 ppm relative to the solid content) of dibutyltin dilaurate (manufactured by Merck), and 13.59 g of 4,4′-diphenylmethane diisocyanate (manufactured by Merck) (isocyanate group/hydroxyl group=0.99 (molar ratio)) were mixed and reacted at 80° C. for 4 hours to obtain a polyurethane resin solution.
The obtained polyurethane resin solution (solid content 30% by mass) was applied to a glass plate, dried at 60°C for 1 hour and at 120°C for 4 hours, and peeled off from the glass plate to obtain a polyurethane resin film.

(Examples 13-15, Comparative Examples 1-3: Synthesis of one-component polyurethane resin and film thereof)
A polyurethane resin solution was obtained by the same reaction method as in Example 12, except that the type of polycarbonate polyol and the mass of the raw materials were changed as shown in Table 2.
The obtained polyurethane resin solution (solid content 30% by mass) was applied to a glass plate, dried at 60°C for 1 hour and at 120°C for 4 hours, and peeled off from the glass plate to obtain a polyurethane resin film.

The evaluation results of the polyurethane resin films obtained in each example and comparative example are shown in Table 2. Other evaluation results of the polyurethane resin films obtained in each example are shown in Table 3.

In the table, the abbreviations indicate the following compounds.
HDL: 1,6-hexanediol PDL: 1,5-pentanediol UH-200: (ETERNACOLL (registered trademark) UH-200, manufactured by Ube Industries, Ltd., polycarbonate diol produced from HDL and dimethyl carbonate) Number average molecular weight: 2000 g/mol Viscosity: 2300 cP (75°C)
UH-200N: (ETERNACOLL (registered trademark) UH-200N, manufactured by Ube Industries, Ltd., polycarbonate diol produced from HDL and dimethyl carbonate) Number average molecular weight: 2000 g/mol Viscosity: 2300 cP (75°C)
PH-200N: (ETERNACOLL (registered trademark) PH-200N, manufactured by Ube Industries, Ltd., a polycarbonate diol produced from HDL, PDL (HDL:PDL = 1:1 (molar ratio)) and dimethyl carbonate), number average molecular weight 2000 g/mol, viscosity 2800 cP (75°C)
UHC50-200: (ETERNACOLL (registered trademark) UHC50-200, manufactured by Ube Industries, Ltd., polycarbonate diol produced from 1,6-hexanediol, dimethyl carbonate, and caprolactone) Number average molecular weight: 2000 g/mol
PCLO-2000: (Sigma-Aldrich, polycaprolactone diol) number average molecular weight 2000 g/mol

Comparison with Examples 12-15 and Comparative Examples 1-3 reveals that by using a polycarbonate polyol having an ester bond and a urethane bond, a polyurethane having a high elastic modulus and a low swelling ratio in hexane and toluene, i.e., high solvent resistance, can be obtained.
A comparison of Examples 12 to 15 shows that by increasing the content of ester bonds and urethane bonds, a polyurethane with a low swelling ratio in toluene can be obtained.
The results in Table 3 show that the polyurethane obtained from the polycarbonate polyol of the present invention also exhibits practical effects in the tests of breaking strength, elongation at break, and chemical resistance.

The present invention provides a polycarbonate polyol that is easy to handle and improves the mechanical properties and solvent resistance of polyurethane resins obtained from the polycarbonate polyol.

Claims (19)

A polycarbonate polyol having an ester bond and a urethane bond and an acid value of 0.01 to 5.0 mgKOH/g, wherein the molar ratio of the urethane bond to the ester bond (urethane/ester) is 0.8 to 1.2 . The polycarbonate polyol according to claim 1 , wherein the content of carbonate bonds is 3 to 23 % by mass based on the total amount of the polycarbonate polyol. The polycarbonate polyol according to claim 1 or 2 , wherein the content of ester bonds is 1.5 to 15 mass% based on the total amount of the polycarbonate polyol, and the content of urethane bonds is 2 to 20 mass% based on the total amount of the polycarbonate polyol. The polycarbonate polyol according to any one of claims 1 to 3 , wherein the content of ester bonds and urethane bonds represented by the following formula (I) is 10 to 90 mol %:
(E+U)/(E+U+C)×100 (I)
(wherein E is the number of moles of ester bonds in the polycarbonate polyol,
U is the number of moles of urethane bonds in the polycarbonate polyol,
C is the number of moles of carbonate bonds in the polycarbonate polyol. The polycarbonate polyol according to any one of claims 1 to 4 , having a hydroxyl value of 25 to 250 mgKOH/g. The polycarbonate polyol according to any one of claims 1 to 5 , having a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2):


(In the formula, ^R1 and ^R2 represent hydrocarbon groups having 2 to 20 carbon atoms.) The polycarbonate polyol according to claim 6 , wherein in the formula, R ¹ is a linear or branched alkylene group having 4 to 7 carbon atoms. The polycarbonate polyol according to any one of claims 1 to 7 , having a number average molecular weight of 400 to 4500 g/mol. The polycarbonate polyol according to any one of claims 1 to 8 , which is liquid at room temperature (25°C). A polyurethane resin-forming composition comprising the polycarbonate polyol (A) according to any one of claims 1 to 9 and a polyisocyanate (C). A polyurethane resin having a structure derived from the polycarbonate polyol (A) according to any one of claims 1 to 9 and a structure derived from a polyisocyanate (C). An aqueous polyurethane resin dispersion comprising a polyurethane resin ,
the polyurethane resin has a structure derived from a polycarbonate polyol (A) and a structure derived from a polyisocyanate (C),
the polycarbonate polyol (A) has an ester bond and a urethane bond and has an acid value of 0.01 to 5.0 mgKOH/g;
Aqueous polyurethane resin dispersion . A coating composition comprising the polyurethane resin of claim 11 . A coating composition comprising the polyurethane resin according to claim 11 . An adhesive composition comprising a polyurethane resin ,
the polyurethane resin has a structure derived from a polycarbonate polyol (A) and a structure derived from a polyisocyanate (C),
the polycarbonate polyol (A) has an ester bond and a urethane bond and has an acid value of 0.01 to 5.0 mgKOH/g;
Adhesive composition . A polyurethane resin film comprising a polyurethane resin ,
the polyurethane resin has a structure derived from a polycarbonate polyol (A) and a structure derived from a polyisocyanate (C),
the polycarbonate polyol (A) has an ester bond and a urethane bond and has an acid value of 0.01 to 5.0 mgKOH/g;
Polyurethane resin film . Synthetic leather containing a polyurethane resin ,
the polyurethane resin has a structure derived from a polycarbonate polyol (A) and a structure derived from a polyisocyanate (C),
the polycarbonate polyol (A) has an ester bond and a urethane bond and has an acid value of 0.01 to 5.0 mgKOH/g;
Synthetic leather . A thermoplastic polyurethane comprising the polyurethane resin of claim 11 . A thermoset cast polyurethane comprising a polyurethane resin ,
the polyurethane resin has a structure derived from a polycarbonate polyol (A) and a structure derived from a polyisocyanate (C),
the polycarbonate polyol (A) has an ester bond and a urethane bond and has an acid value of 0.01 to 5.0 mgKOH/g;
Thermoset and cast polyurethane .