JP7662982B2 - Curable material, curable composition, cured product, method for producing polycarbonate polymer, and polycarbonate polymer - Google Patents

Description

The present invention relates to a curable material made of a polycarbonate polymer, a curable composition containing the curable material, a cured product of the curable composition, a method for producing a polycarbonate polymer, and a polycarbonate polymer.

Polymers having reactive silicon groups cure by hydrolysis to form flexible rubber-like cured products, which are used in applications such as sealants and adhesives. In order to optimize the curability of curable compositions containing polymers having reactive silicon groups, and the physical properties of the cured products, studies are being conducted on polymers having reactive silicon groups and other components in the curable compositions.

As a polymer having a reactive silicon group, Patent Document 1 describes a polymer in which a reactive silicon group is linked to the end of a polyoxyalkylene chain derived from a polyoxyalkylene polyol via a urethane bond.

Japanese Patent Application Publication No. 3-157424

In applications such as adhesives and sealants, the cured product is required to have excellent strength and elongation. However, there is generally a trade-off between strength and elongation, making it difficult to achieve both.
The present invention provides a polycarbonate polymer having good strength and elongation when cured, a method for producing the same, a curable material comprising the polycarbonate polymer, a curable composition containing the curable material, and a cured product of the curable composition.

The present invention has the following aspects.
[1] A curable material comprising a polycarbonate polymer having a number average molecular weight of 4,000 to 50,000, the polycarbonate polymer having in each molecule a reactive silicon group represented by the following formula 1, a carbonate group, and a unit based on alkylene oxide:
-SiX _a R ¹ _3-a formula 1
In formula 1, R ¹ represents a monovalent organic group having 1 to 20 carbon atoms other than a hydrolyzable group, X represents a hydroxyl group or a hydrolyzable group, a represents an integer of 1 to 3, and when a is 1, R ¹ may be the same as or different from one another, and when a is 2 or 3, X may be the same as or different from one another.
[2] The curable material of [1], wherein the alkylene oxide-based units include propylene oxide-based units.
[3] The curable material according to [1] or [2], wherein the number of carbonate groups per molecule of the polycarbonate polymer is 3.0 or more.
[4] The curable material according to any one of [1] to [3], wherein a carbonate group/alkylene oxide unit ratio, which represents a molar ratio of the content of the carbonate group to the content of the unit based on the alkylene oxide, is 0.01 to 1.
[5] The curable material according to any one of [1] to [4], wherein the number of the reactive silicon groups present in the polycarbonate polymer is more than 0.5 on average per molecule.
[6] The curable material according to any one of [1] to [5], having a molecular weight distribution of 1.0 to 3.0.
[7] A curable composition comprising the curable material according to any one of [1] to [6] above and a curing catalyst.
[8] A cured product of the curable composition according to [7] above.
[9] The cured product of [8], which is used as a sealing material.
[10] The cured product of [8], which is used as an adhesive.

[11] A method for producing a polycarbonate polymer, comprising reacting a precursor polymer having a number average molecular weight of 4,000 to 50,000, which has two or more carbonate groups, a unit based on an alkylene oxide, and an active hydrogen-containing group at its terminal that can react with a silylating agent, or a derivative of the precursor polymer in which a reactive terminal group that can react with a silylating agent has been introduced at its terminal, with a silylating agent which has a reactive silicon group represented by the following formula 1 and has a group that can react with the active hydrogen-containing group or the reactive terminal group:
-SiX _a R ¹ _3-a formula 1
In formula 1, R ¹ represents a monovalent organic group having 1 to 20 carbon atoms other than a hydrolyzable group, X represents a hydroxyl group or a hydrolyzable group, a represents an integer of 1 to 3, and when a is 1, R ¹ may be the same as or different from one another, and when a is 2 or 3, X may be the same as or different from one another.
[12] The method for producing a polycarbonate polymer according to [11], wherein the precursor polymer is obtained by addition polymerization of an alkylene oxide to a hydroxyl group of a polycarbonate polyol.
[13] The method for producing a polycarbonate polymer according to [11], wherein the precursor polymer is obtained by addition polymerization of an alkylene oxide and carbon dioxide to a hydroxyl group of a polycarbonate polyol.
[14] The method for producing a polycarbonate polymer according to [12] or [13], wherein the polycarbonate polyol is a polycarbonate diol obtained by condensation polymerization of a diol compound represented by the following formula 2 and a carbonate compound represented by the following formula 3:
HO-R ² -OH Formula 2
In formula 2, ^R2 represents a substituted or unsubstituted divalent hydrocarbon group having 3 to 20 carbon atoms.
R ³ -O-C(O)-O-R ⁴ Formula 3
In formula 3, R ³ and R ⁴ are each independently an alkyl group having 1 to 20 carbon atoms or a phenyl group, or R ³ and R ⁴ are bonded to each other to form a ring.
[15] The method for producing a polycarbonate polymer according to [14], wherein the diol compound is at least one selected from the group consisting of 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,4-cyclohexanedimethanol, and isosorbide.
[16] The method for producing a polycarbonate polymer according to [14] or [15], wherein the polycarbonate diol has a number average molecular weight of 250 to 10,000.
[17] The method for producing a polycarbonate polymer according to [11], wherein the precursor polymer is obtained by addition polymerization of an alkylene oxide and carbon dioxide to a polyol not containing a carbonate group.
[18] A polycarbonate polymer having a reactive silicon group represented by the following formula 1, a carbonate group, and a unit based on alkylene oxide in one molecule, and having a number average molecular weight of 4,000 to 50,000:
-SiX _a R ¹ _3-a formula 1
In formula 1, R ¹ represents a monovalent organic group having 1 to 20 carbon atoms other than a hydrolyzable group, X represents a hydroxyl group or a hydrolyzable group, a represents an integer of 1 to 3, and when a is 1, R ¹ may be the same as or different from one another, and when a is 2 or 3, X may be the same as or different from one another.
[19] A polycarbonate polymer having, in one molecule, a reactive silicon group represented by the following formula 10, two or more carbonate groups, and a repeating unit based on alkylene oxide, and having a number average molecular weight of 4,000 to 50,000:
-SiX ¹⁰ _a R ¹⁰ _3-a Formula 10
In formula 10, R ¹⁰ represents a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent halohydrocarbon group having 1 to 20 carbon atoms, X ¹⁰ represents a hydroxyl group or an alkoxy group having 1 to 3 carbon atoms, and a represents an integer of 1 to 3. When a is 1, R ¹⁰ may be the same as or different from each other, and when a is 2 or 3, X ¹⁰ may be the same as or different from each other.
[20] A polycarbonate polymer having one or more reactive silicon groups, two or more carbonate groups, and a repeating unit based on alkylene oxide in one molecule, and having a number average molecular weight of 4,000 to 50,000, and represented by the following formula 11:
X ¹⁰ _a R ¹⁰ _3-a Si-Q-[(OR ¹¹ ) _n (OR ¹¹ -O-C(O)) _m (OR ² -O-C(O)) _t ]-O-R ²¹ -O-Q-SiX ¹⁰ _a R ¹⁰ _3-a Formula 11
In formula 11, ^X10 represents a hydroxyl group or an alkoxy group having 1 to 3 carbon atoms, ^R10 represents a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent halohydrocarbon group having 1 to 20 carbon atoms, Q represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 6 carbon atoms or -C(O)NH - ^R31- , ^R31 represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 6 carbon atoms with one bond bonded to a silicon atom, ^R11 represents a substituted or unsubstituted divalent hydrocarbon group having 2 to 4 carbon atoms, ^R2 and ^R21 each independently represent a substituted or unsubstituted divalent hydrocarbon group having 3 to 20 carbon atoms, n is an integer from 1 to 900, t is an integer from 0 to 50, m is an integer from 0 to 500, and n+t+m is an integer of 3 or greater. a is an integer of 1 to 3. When a is 1, R ¹⁰ may be the same or different from each other, and when a is 2 or 3, X ¹⁰ may be the same or different from each other.

The curable material of the present invention has excellent strength and elongation when cured.
The curable composition of the present invention gives a cured product having good strength and elongation.
The cured product of the present invention has good strength and elongation.
The polycarbonate polymer of the present invention has excellent strength and elongation when cured.

As used in the specification and claims, the following terms have the following definitions:
The term "unit" constituting a polymer means an atomic group formed by polymerization of a monomer.
The number average molecular weight (hereinafter, referred to as "Mn") and the weight average molecular weight (hereinafter, referred to as "Mw") are molecular weights calculated as oxyalkylene polymers measured by gel permeation chromatography (GPC) using a calibration curve prepared using an oxyalkylene polymer with a known hydroxyl-converted molecular weight. The molecular weight distribution is a value calculated from Mw and Mn, and is the ratio of Mw to Mn (hereinafter, referred to as "Mw/Mn"). The "hydroxyl-converted molecular weight" is a molecular weight calculated using a value obtained by applying the hydroxyl value calculated based on JIS K 1557 (2007) to the formula "56,100 x (number of hydroxyl groups in molecule)/(hydroxyl value)" for an oxyalkylene polymer containing a repeating unit based on an alkylene oxide monomer.

The term "precursor polymer" refers to a polymer before the introduction of reactive silicon groups, which has a carbonate group and a unit based on alkylene oxide (hereinafter also referred to as "alkylene oxide unit") and has an active hydrogen-containing group at its terminal.
The term "derivative of a precursor polymer" refers to a polymer in which a reactive terminal group has been introduced to the end of the precursor polymer via a linking group. The reactive terminal group can react with a silylating agent described below.
The term "reactive end group" refers to an end group that reacts with a silylating agent when a reactive silicon group is introduced into a precursor polymer or its derivative. Examples of reactive end groups include alkenyloxy groups such as allyloxy groups, and hydroxyl groups. The number of alkenyloxy groups present in a polymer can be calculated by a method for measuring the unsaturated group concentration by titration analysis based on the principle of the iodine value measurement method specified in JIS K 0070 (1992).
The term "silylating agent" refers to a compound capable of reacting with an active hydrogen-containing group or the reactive terminal group to form a terminal group having a reactive silicon group.
By "non-reactive end group" is meant an end group that does not react with the silylating agent.

In this specification, the "silylation rate" of a polycarbonate polymer is the ratio of the number of reactive silicon groups to the total number of reactive silicon groups, reactive end groups, and non-reactive end groups present in the polycarbonate polymer. The value of the silylation rate can be measured by NMR analysis. When the reactive end groups in the polycarbonate polymer are active hydrogen-containing groups, the number of reactive end groups is the number of active hydrogens. The total number of the reactive silicon groups, reactive end groups, and non-reactive end groups is also referred to as the number of all end groups.
The total number of terminal groups of a polycarbonate polymer is equal to the total number of reactive terminal groups and non-reactive terminal groups of a precursor polymer or its derivative. For example, when a derivative in which an unsaturated group is introduced as a reactive terminal group is used in a precursor polymer, a non-reactive terminal group (e.g., 1-propenyl group) may be present due to isomerization of the unsaturated group when the unsaturated group (e.g., allyl group) is introduced into the precursor polymer.

<Polycarbonate polymer>
The polycarbonate polymer of the present embodiment has a reactive silicon group, a carbonate group, and an alkylene oxide unit represented by the following formula 1 in one molecule.

The reactive silicon group has a hydroxyl group or a hydrolyzable group bonded to a silicon atom, and can form a siloxane bond to crosslink. The reaction to form a siloxane bond is accelerated by a curing catalyst. The hydrolyzable group is a group that can react with water to form a silanol group. The reactive silicon group in polymer A is represented by the following formula 1.
-SiX _a R ¹ _3-a formula 1

In the formula 1, ^R1 represents a monovalent organic group having 1 to 20 carbon atoms. ^R1 does not contain a hydrolyzable group.
R ¹ is preferably at least one selected from the group consisting of a hydrocarbon group having 1 to 20 carbon atoms, a halohydrocarbon group, and a triorganosiloxy group, more preferably at least one selected from the group consisting of a monovalent hydrocarbon group having 1 to 20 carbon atoms, and a monovalent halohydrocarbon group having 1 to 20 carbon atoms, and particularly preferably at least one selected from the group consisting of a monovalent hydrocarbon group having 1 to 3 carbon atoms, and a halohydrocarbon group having 1 to 3 carbon atoms.

R ¹ is preferably an alkyl group, a cycloalkyl group, an aryl group, a 1-chloroalkyl group, or a triorganosiloxy group. A linear or branched alkyl group having 1 to 4 carbon atoms, a cyclohexyl group, a phenyl group, a benzyl group, a 1-chloroalkyl group, a trimethylsiloxy group, a triethylsiloxy group, or a triphenylsiloxy group is more preferred, and an alkyl group having 1 to 3 carbon atoms or a 1-chloroalkyl group having 1 to 3 carbon atoms is particularly preferred. In terms of good curability of the polymer having a reactive silicon group and stability of the curable composition, a methyl group or an ethyl group is preferred. In terms of a high curing rate of the cured product, a 1-chloromethyl group is preferred. In terms of easy availability, a methyl group is particularly preferred.

In the above formula 1, X represents a hydroxyl group or a hydrolyzable group.
Examples of hydrolyzable groups include halogen atoms, alkoxy groups, acyloxy groups, ketoximate groups, amino groups, amide groups, acid amide groups, aminooxy groups, sulfanyl groups, and alkenyloxy groups. The number of carbon atoms of the alkyl or alkenyl groups that may be present in these groups is preferably 1 to 6, and more preferably 1 to 3.
From the viewpoint of mild hydrolysis and ease of handling, an alkoxy group is preferred, and an alkoxy group having 1 to 3 carbon atoms is more preferred. The alkoxy group is preferably a methoxy group, an ethoxy group, or an isopropoxy group, and more preferably a methoxy group or an ethoxy group. When the alkoxy group is a methoxy group or an ethoxy group, a siloxane bond is rapidly formed and a crosslinked structure is easily formed in the cured product, and the physical properties of the cured product are improved.

In the formula 1, a represents an integer of 1 to 3. When a is 1, R ¹ may be the same or different from each other. When a is 2 or more, X may be the same or different from each other.
a is preferably 1 or 2, and a is more preferably 2.

Examples of the reactive silicon group represented by the formula 1 include a trimethoxysilyl group, a triethoxysilyl group, a triisopropoxysilyl group, a tris(2-propenyloxy)silyl group, a triacetoxysilyl group, a dimethoxymethylsilyl group, a diethoxymethylsilyl group, a dimethoxyethylsilyl group, a diisopropoxymethylsilyl group, a chloromethyldimethoxysilyl group, and a chloromethyldiethoxysilyl group. In terms of high activity and good curability, a trimethoxysilyl group, a triethoxysilyl group, a methyldimethoxysilyl group, and a methyldiethoxysilyl group are preferred, and a dimethoxymethylsilyl group and a trimethoxysilyl group are more preferred.
As the reactive silicon group represented by the above formula 1, a group represented by the following formula 10 is preferred.
-SiX ¹⁰ _a R ¹⁰ _3-a Formula 10
In formula 10, R ¹⁰ represents a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent halohydrocarbon group having 1 to 20 carbon atoms, X ¹⁰ represents a hydroxyl group or an alkoxy group having 1 to 3 carbon atoms, and a represents an integer of 1 to 3. When a is 1, R ¹⁰ may be the same as or different from each other, and when a is 2 or 3, X ¹⁰ may be the same as or different from each other.
R ¹⁰ is more preferably a linear or branched alkyl group having 1 to 4 carbon atoms, a cyclohexyl group, a phenyl group, a benzyl group, a 1-chloroalkyl group, a trimethylsiloxy group, a triethylsiloxy group, or a triphenylsiloxy group, and is particularly preferably an alkyl group having 1 to 3 carbon atoms or a 1-chloroalkyl group having 1 to 3 carbon atoms. In terms of good curability of the polymer having a reactive silicon group and good stability of the curable composition, a methyl group or an ethyl group is preferred. In terms of a fast curing rate of the cured product, a 1-chloromethyl group is preferred. In terms of easy availability, a methyl group is particularly preferred.
The alkoxy group of X ¹⁰ is preferably a methoxy group, an ethoxy group, or an isopropoxy group, and more preferably a methoxy group or an ethoxy group. When the alkoxy group is a methoxy group or an ethoxy group, a siloxane bond is rapidly formed and a crosslinked structure is easily formed in the cured product, and the physical properties of the cured product are better.
a is preferably 1 or 2, and a is more preferably 2.
The reactive silicon group represented by the formula 10 is preferably a trimethoxysilyl group, a triethoxysilyl group, a methyldimethoxysilyl group, or a methyldiethoxysilyl group, and more preferably a dimethoxymethylsilyl group or a trimethoxysilyl group.

The number of reactive silicon groups present in the polycarbonate polymer is preferably more than 0.5 and not more than 6.0 on average per molecule, more preferably 1.2 to 3.8, and even more preferably 1.4 to 2.0. If the number is equal to or greater than the lower limit of the above range, the strength of the cured product of the curable composition will be better, and if the number is equal to or less than the upper limit, the elongation of the cured product of the curable composition will be better.

The alkylene oxide units are preferably units based on at least one selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, and tetramethylene oxide. It is preferable that the alkylene oxide units contain units based on propylene oxide, since this makes the curable composition less viscous and therefore easier to handle, and the cured product more flexible.

The Mn of the polycarbonate polymer of the present invention is 4,000 to 50,000, preferably 5,000 to 30,000, and more preferably 6,000 to 25,000. Within this range, the cured product has better elongation and the curable composition has a lower viscosity, making it easier to handle.
The Mw/Mn of the polycarbonate polymer of the present embodiment is preferably 1.0 to 3.0, more preferably 1.01 to 2.50, even more preferably 1.02 to 2.20, and particularly preferably 1.03 to 2.00, in order to provide a curable composition with a lower viscosity.

The number of carbonate groups present in the polycarbonate polymer is 2 or more, preferably 3 or more on average per molecule, more preferably 4 or more. When the number is equal to or more than the above lower limit, the strength of the cured product of the curable composition becomes better. From the viewpoint of the viscosity of the polymer, the upper limit of the number of carbonate groups is preferably 50 or less, more preferably 40 or less.
The number of carbonate groups per molecule of a polycarbonate polymer can be calculated by NMR analysis.

In the polycarbonate polymer of this embodiment, carbonate group/alkylene oxide unit, which represents the molar ratio of the carbonate group content to the alkylene oxide unit content, is preferably 0.01 to 1, more preferably 0.02 to 0.5, and even more preferably 0.03 to 0.4. If it is equal to or greater than the lower limit of the above range, it is preferable in that the strength of the cured product of the curable composition is improved, and if it is equal to or less than the upper limit, it is preferable in that the curable composition has a lower viscosity, making it easier to handle, and the strength of the cured product of the curable composition is improved.

The terminal group of the polycarbonate polymer of this embodiment is any one of a reactive silicon group, a reactive terminal group, and a non-reactive terminal group. Examples of the reactive terminal group include an unsaturated group, an active hydrogen-containing group, and an isocyanate group present at the terminal. The terminal groups present in one molecule may be the same or different from each other.
The silylation rate is preferably more than 50 mol % and not more than 100 mol %, more preferably from 55 to 99 mol %, and even more preferably from 60 to 98 mol %.

<Production Method>
The polycarbonate polymer of the present embodiment can be produced by a method of reacting a precursor polymer having a carbonate group and an alkylene oxide unit and having an active hydrogen-containing group at a terminal, or a derivative of the precursor polymer, with a silylating agent having a reactive silicon group.
Examples of the active hydrogen-containing group include a hydroxyl group, a carboxyl group, an amino group, a monovalent functional group obtained by removing a hydrogen atom from a primary amine, a hydrazide group, and a sulfanyl group. As the active hydrogen-containing group, a hydroxyl group, an amino group, and a monovalent functional group obtained by removing one hydrogen atom bonded to a nitrogen atom in a primary amine are preferred, and a hydroxyl group is more preferred.

The Mn of the precursor polymer is preferably from 4,000 to 50,000, more preferably from 5,000 to 30,000, and even more preferably from 6,000 to 25,000.
The Mw/Mn of the precursor polymer is preferably from 1.0 to 3.0, more preferably from 1.01 to 2.50, even more preferably from 1.02 to 2.20, and particularly preferably from 1.03 to 2.00, in order to improve the elongation of the cured product.
The viscosity of the precursor polymer at 25° C. is preferably 100 to 100,000 mPa·s, more preferably 1,000 to 80,000 mPa·s, and even more preferably 2,800 to 60,000 mPa·s. A viscosity of at least the lower limit of the above range is preferred in that the curable composition is easy to handle, and a viscosity of not more than the upper limit of the above range is preferred in that the strength of the cured product is improved.

The precursor polymer having an active hydrogen-containing group at its terminal can be produced by addition polymerization of a monomer described later to the active hydrogen-containing group of an initiator described later.
The precursor polymer derivative can be obtained by introducing one or more reactive end groups to the ends of the precursor polymer. The number of reactive end groups present in the precursor polymer or its derivative is preferably 1 to 4, and more preferably 1 to 2.

The precursor polymer or a derivative thereof can be reacted with a silylating agent by a known method.
For example, a preferred method is to react a derivative in which one or more unsaturated groups are introduced at the terminal of a precursor polymer with a silylating agent having a functional group reactive with the unsaturated group.
Alternatively, a method is preferred in which a silylating agent having an isocyanate group, which is a functional group that reacts with an active hydrogen-containing group, is used to cause a urethane reaction between the active hydrogen-containing group of the precursor polymer and the silylating agent.

Examples of silylating agents having a functional group that reacts with an unsaturated group include compounds having a sulfanyl group and a reactive silicon group, and hydrosilane compounds (for example, HSiX _a R ¹ _3-a , where X, R ^1, and a are the same as those in formula 1). Specific examples include trimethoxysilane, triethoxysilane, triisopropoxysilane, tris(2-propenyloxy)silane, triacetoxysilane, methyldimethoxysilane, methyldiethoxysilane, ethyldimethoxysilane, methyldiisopropoxysilane, (α-chloromethyl)dimethoxysilane, and (α-chloromethyl)diethoxysilane. In terms of high activity and good curing properties, trimethoxysilane, triethoxysilane, methyldimethoxysilane, and methyldiethoxysilane are preferred, and methyldimethoxysilane or trimethoxysilane is more preferred.
Examples of silylating agents having an isocyanate group include isocyanate silane compounds described in JP 2011-178955 A, specifically, 1-isocyanate methyl dimethoxy methyl silane, 1-isocyanate methyl diethoxy ethyl silane, 1-isocyanate propyl methyl dimethoxy silane, 3-isocyanate propyl methyl dimethoxy silane, 3-isocyanate propyl ethyl diethoxy silane. 1-isocyanate methyl dimethoxy methyl silane and 1-isocyanate propyl methyl dimethoxy silane are preferred.

As the method of introducing one unsaturated group into one end of a precursor polymer and then reacting the unsaturated group with a silylating agent, or the method of subjecting an active hydrogen-containing group of the precursor polymer to a urethanization reaction with an isocyanate silane compound, a conventionally known method can be used. For example, the methods proposed in JP-B-45-36319, JP-A-50-156599, JP-A-61-197631, JP-A-3-72527, JP-A-8-231707, JP-A-2011-178955, U.S. Pat. No. 3,632,557, and U.S. Pat. No. 4,960,844 can be mentioned.
A preferred method for introducing two unsaturated groups into one end of a precursor polymer is to react an alkali metal salt with the precursor polymer, then react with an epoxy compound having an unsaturated group, and then react with a halogenated hydrocarbon compound having an unsaturated group.

As a method for introducing more than one unsaturated group into one end of the precursor polymer, any known method can be used without particular limitation. For example, the methods described in WO 2013/180203, WO 2014/192842, JP 2015-105293, JP 2015-105322, JP 2015-105323, JP 2015-105324, WO 2015/080067, WO 2015/105122, WO 2015/111577, WO 2016/002907, JP 2016-216633, and JP 2017-39782 can be used.

As the method for producing the polycarbonate polymer of the present invention, the following embodiments 1 to 3 are preferred.
[Aspect 1]
In embodiment 1, a polycarbonate polyol is used as the initiator.
The number of hydroxyl groups in the polycarbonate polyol is 2 or more, preferably 2 to 5, and more preferably 2.0 to 3.5.
The polycarbonate polyol is preferably a polycarbonate diol represented by the following formula 4. In addition, as the polycarbonate polyol, an oligomer (polycarbonate polyol) in which an alkylene oxide and carbon dioxide are added to a polyol can also be used.

The polycarbonate diol represented by the following formula 4 is a condensation polymer of a diol compound represented by the following formula 2 and a carbonate compound represented by the following formula 3. That is, the polycarbonate diol represented by the following formula 4 is composed of a unit based on the diol compound represented by the following formula 2 (hereinafter also referred to as a "diol unit") and a unit based on a carbonate compound represented by the following formula 3. The diol units present in the polycarbonate diol may be of one type or two or more types. From the viewpoint of lowering the viscosity of the curable composition and increasing the maximum point cohesive strength of the cured product, 2 to 5 types are preferred, and 2 or 3 types are more preferred.

HO-R ² -OH Formula 2
In formula 2, ^R2 represents a substituted or unsubstituted divalent hydrocarbon group having 3 to 20 carbon atoms.
R ³ -O-C(O)-O-R ⁴ Formula 3
In formula 3, R ³ and R ⁴ are each independently an alkyl group having 1 to 20 carbon atoms or a phenyl group, or R ³ and R ⁴ are bonded to each other to form a ring.
H-[O-R ² -O-C(O)] _a -O-R ² -OH Formula 4
In formula 4, ^R2 is the same as ^R2 in formula 2. a is an integer of 1.0 or more, and preferably 3.0 or more.

In formula 2, ^R2 may be a substituted or unsubstituted chain hydrocarbon group or a substituted or unsubstituted cyclic hydrocarbon group. When ^R2 is composed of two or more types of hydrocarbon groups, the arrangement of -[O- ^R2 -O-C(O)]- in formula 4 may be random, block, or a combination of both.
The chain hydrocarbon group is more preferably a linear or branched alkyl group having 3 to 20 carbon atoms.
The cyclic hydrocarbon group is, for example, a group represented by -R ⁵ -R ⁶ -R ⁵ -. R ⁵ represents a single bond or an alkylene group having 1 to 6 carbon atoms. R ⁶ represents a substituted or unsubstituted alicyclic hydrocarbon group having 3 to 9 carbon atoms and a monocyclic structure, a substituted or unsubstituted alicyclic hydrocarbon group having 4 to 16 carbon atoms and a polycyclic structure, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms. In the alicyclic hydrocarbon group, one or more carbon atoms constituting the ring may be substituted with an oxygen atom. However, adjacent carbon atoms are not substituted with oxygen atoms at the same time.
The alkylene group having 1 to 6 carbon atoms of ^R5 may be linear or branched. When ^R5 is an alkylene group having 1 to 6 carbon atoms, the number of carbon atoms is preferably 1 to 4, and more preferably 1 or 2. Examples of ^R5 include a single bond, a methylene group, an ethylene group, an n-propylene group, an n-butylene group, an n-pentylene group, an n-hexylene group, an isopropylene group, an isobutylene group, and a t-butylene group, of which a single bond, a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, an isobutylene group, and a t-butylene group are preferred, and a single bond, a methylene group, and an ethylene group are more preferred.
When R ⁶ is a divalent alicyclic saturated hydrocarbon group having 3 to 9 carbon atoms and an unsubstituted monocyclic structure, the number of carbon atoms of R ⁶ is preferably 4 to 8, more preferably 5 to 8, and even more preferably 5 or 6, because this provides better stability against heat and light. Examples of the divalent alicyclic saturated hydrocarbon group having 3 to 9 carbon atoms and an unsubstituted monocyclic structure of R ⁶ include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, a cyclooctylene group, and a cyclononylene group, and a cyclopentylene group and a cyclohexylene group are preferred.
When R ⁶ is a divalent alicyclic saturated hydrocarbon group having 4 to 16 carbon atoms and an unsubstituted polycyclic structure, the number of carbon atoms in R ⁶ is preferably 4 to 15, and more preferably 6 to 12, in order to provide a cured product with better hardness and chemical resistance. ^{R 6} is preferably a group having 2 or 3 ring structures, and more preferably a group having 2 ring structures.
When ^R6 is an unsubstituted divalent aromatic hydrocarbon group having 6 to 18 carbon atoms, the hardness and chemical resistance of the cured product are more excellent, so the number of carbon atoms in ^R6 is preferably 6 to 14, and more preferably 6 to 12. Examples of the unsubstituted divalent aromatic hydrocarbon group having 6 to 18 carbon atoms include a phenylene group and a biphenylene group, and the phenylene group is preferred because the hardness and chemical resistance of the cured product are more excellent.
When ^R6 is a divalent alicyclic saturated hydrocarbon group having 3 to 9 carbon atoms and a monocyclic structure having a substituent, the monocyclic structure is the same as the above-mentioned divalent alicyclic saturated hydrocarbon group having an unsubstituted monocyclic structure and having 3 to 9 carbon atoms.
When ^R6 is a divalent alicyclic saturated hydrocarbon group having 4 to 16 carbon atoms and a polycyclic structure having a substituent, the polycyclic structure is the same as the above-mentioned divalent alicyclic saturated hydrocarbon group having 4 to 16 carbon atoms and an unsubstituted polycyclic structure.
When R ⁶ is a substituted divalent aromatic hydrocarbon group having 6 to 18 carbon atoms, the aromatic hydrocarbon group is the same as the unsubstituted divalent aromatic hydrocarbon group having 6 to 18 carbon atoms described above.
The number of carbon atoms in R ⁶ indicates only the number of carbon atoms constituting the ring, and does not include the number of carbon atoms in the substituent. Examples of the substituent include a halogen atom, an alkyl group, and an alkoxy group. Examples of the alkyl group 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, a nonyl group, and a decyl group. Examples of the substituent include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, a methoxy group, an ethoxy group, and a halogen atom, and more preferably a methyl group, an ethyl group, a t-butyl group, a methoxy group, an ethoxy group, and a chlorine atom. The number of the substituent is preferably 0 to 4, and more preferably 0 to 2.
When ^R6 is an alicyclic saturated hydrocarbon group having a monocyclic or polycyclic structure and one or more carbon atoms constituting the ring are substituted with oxygen atoms, the ratio of the number of oxygen atoms to the total number of atoms constituting the ring is preferably 5 to 50%, more preferably 10 to 30%.

Examples of the diol compound represented by formula 2 include ethylene glycol, 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, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, and 1,15-tetradecanediol. diols having no side chains, such as 1,16-hexadecanediol, 1,18-octadecanediol, and 1,20-eicosanediol; 2-methyl-1,8-octanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2-ethyl-1,3-hexanediol, 2-methyl-1,4-butanediol, 2-methyl-1,3-propanediol, 3-methyl-1, Examples of the diols include diols having a side chain such as 5-pentanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, and 2,2-dimethyl-1,3-propanediol; cyclic diols such as 1,3-cyclohexanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, isosorbide, 2-bis(4-hydroxycyclohexyl)-propane, 2,3-norbornanediol, tetrahydrofuran-2,2-dimethanol, 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, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,7-heptanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 2-methyl-1,8-octanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 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, 2,2 Dimethyl-1,3-propanediol, 1,3-cyclohexanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2-bis(4-hydroxycyclohexyl)-propane 2,7-norbornanediol, tetrahydrofuran dimethanol, 2,5-bis(hydroxymethyl)-1,4-dioxane and isosorbide are preferred, 1,4-butanediol, 1,10-decanediol, 2-ethyl-1,6-hexanediol, 1,4-cyclohexanedimethanol and isosorbide are more preferred, and 1,4-butanediol, 1,10-decanediol and isosorbide are even more preferred.

In formula 3, R ³ and R ⁴ are each independently an alkyl group having 1 to 20 carbon atoms or a phenyl group. When R ³ and R ⁴ are bonded to each other to form a ring, R ³ and R ⁴ in (-O-R ³ -R ⁴ -O-) are each independently an alkylene group having 1 to 3 carbon atoms or an alkylene group having 1 to 3 carbon atoms in which at least one hydrogen atom is substituted with an alkyl group having 1 to 4 carbon atoms.
Examples of the carbonate compound represented by formula 3 include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, diphenyl carbonate, ethylene carbonate, trimethylene carbonate, propylene carbonate, 1,2-butylene carbonate, and neopentylene carbonate.
Among these, dimethyl carbonate, diethyl carbonate, diphenyl carbonate and ethylene carbonate are preferred in that the viscosity of the curable composition is lower and the strength of the cured product is better. Dimethyl carbonate and diethyl carbonate are preferred in that the boiling point of the compound eliminated during the reaction is low, so that the equilibrium reaction tends to lean toward the target compound, and diphenyl carbonate is preferred in that the boiling point difference between the compound eliminated during the reaction and the target compound is large, so that the target compound can be easily separated.
As a method for producing a polycarbonate diol represented by formula 4 by condensation polymerization of a diol compound represented by formula 2 and a carbonate compound represented by formula 3, for example, the methods described in JP-A-2012-77280, JP-A-2014-080590, JP-A-2015-91937, Japanese Patent No. 3724561, Japanese Patent No. 5532592, Japanese Patent No. 1822688, and Japanese Patent No. 4-2390234 can be used.

The Mn of the polycarbonate diol represented by formula 4 is preferably 250 to 10,000, more preferably 300 to 5,000. When it is equal to or more than the lower limit of the above range, the weather resistance and chemical resistance of the cured product tend to be good, and when it is equal to or less than the upper limit, the viscosity of the curable composition becomes lower, making it easier to handle.
The Mw/Mn of the polycarbonate diol represented by formula 4 is preferably 3.0 or less, more preferably 2.5 or less, and even more preferably 2.0 or less. When it is equal to or less than the upper limit, the curable composition has a lower viscosity and is easy to handle.

The oligomer (polycarbonate polyol) has at least a structure represented by the following formula 5. That is, it contains a carbonate group. In formula 5, -AO- represents a unit in which an alkylene oxide is ring-opened.
-[AO-C(O)O]- Formula 5
The oligomer (polycarbonate polyol) is preferably an oligomer (polycarbonate diol) in which an alkylene oxide and carbon dioxide are added to a diol compound.
In the oligomer (polycarbonate diol), the diol compound is preferably the diol compound represented by the formula 2.
Examples of the alkylene oxide include ethylene oxide, propylene oxide, 1,2-butylene oxide, and 2,3-butylene oxide. Propylene oxide is particularly preferred. The arrangement of the alkylene oxide-based units and the carbon dioxide-based units may be random, block, or a combination of both.
As a method for addition-polymerizing an alkylene oxide and carbon dioxide to a hydroxyl group of a diol compound in the presence of a ring-opening polymerization catalyst, for example, the methods described in JP-A-2009-544801, U.S. Patent Application Publication No. 2012/0289732, WO 2013/034750, JP-T-2011-522091, and JP-T-2012-500867 can be used.
The Mn of the oligomer (polycarbonate diol) is preferably from 100 to 5,000, and more preferably from 150 to 3,000, in view of good reactivity with alkylene oxide when forming the oligomer.
The Mw/Mn of the oligomer (polycarbonate diol) is preferably 3.0 or less, more preferably 2.5 or less, and even more preferably 2.0 or less, in terms of improving the elongation of the cured product.

In embodiment 1, an alkylene oxide is subjected to ring-opening addition polymerization to the hydroxyl groups (active hydrogen-containing groups) of a polycarbonate polyol, which is an initiator, in the presence of a ring-opening polymerization catalyst. This produces a precursor polymer (hereinafter also referred to as "precursor polymer a1") having a polyoxyalkylene chain composed of alkylene oxide units and terminated with a hydroxyl group. The number of hydroxyl groups in the polycarbonate polyol is the same as the number of active hydrogen-containing groups in the precursor polymer a1.
A precursor polymer a1 or a derivative of the precursor polymer a1 having one or more reactive terminal groups introduced at the terminal thereof is reacted with a silylating agent to obtain a polycarbonate polymer A1.

In the embodiment 1, the ring-opening addition polymerization catalyst used in the ring-opening addition polymerization of the alkylene oxide to the initiator is not particularly limited, and examples thereof include composite metal cyanide complex 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. Composite metal cyanide complex catalysts are preferred in that they are easy to obtain a precursor polymer a1 having a narrow Mw/Mn and low viscosity. Examples of the ligand of the composite metal cyanide complex catalyst include t-butyl alcohol, ethylene glycol dimethyl ether (glyme), and diethylene glycol dimethyl ether (diglyme). Of these, t-butyl alcohol is preferred in that it is easier to obtain a precursor polymer a1 having a narrow Mw/Mn ratio and a low viscosity.
The composite metal cyanide complex catalyst is not particularly limited, and a conventionally known compound can be used, and a method for producing a polymer using a composite metal cyanide complex can be a known method, including the amount added, etc. For example, the compounds and production methods disclosed in International Publication No. 2003/062301, International Publication No. 2004/067633, JP-A-2004-269776, JP-A-2005-15786, International Publication No. 2013/065802, and JP-A-2015-010162 can be used.

The alkylene oxide units constituting the polyoxyalkylene chain of the precursor polymer a1 may be of one type or of two or more types. When the polyoxyalkylene chain has two or more types of alkylene oxide units, the arrangement of the units may be random, block, or a combination of both.

The Mn of the precursor polymer a1 is preferably from 4,000 to 50,000, more preferably from 5,000 to 30,000, and even more preferably from 6,000 to 25,000.
The Mw/Mn of the precursor polymer a1 is preferably from 1.0 to 3.0, more preferably from 1.01 to 2.50, further preferably from 1.02 to 2.20, and particularly preferably from 1.03 to 2.00.
The precursor polymer a1 may be a solid, and if it is a solid, it is preferable that it becomes liquid when heated to 90° C. When the precursor polymer a1 is a liquid at 25° C., the viscosity of the precursor polymer a1 at 25° C. is preferably 100 to 100,000 mPa·s, more preferably 1,000 to 80,000 mPa·s, and more preferably 2,800 to 60,000 mPa·s. If it is equal to or greater than the lower limit of the above range, it is preferable in that the curable composition is easy to handle, and if it is equal to or less than the upper limit, it is preferable in that the strength of the cured product is better.

In the polycarbonate polymer A1, the molar ratio of carbonate groups/alkylene oxide units is preferably from 0.01 to 1.00, and more preferably from 0.02 to 0.50, in view of the lower viscosity of the curable composition and therefore ease of handling.
The Mn of the polycarbonate polymer A1 is preferably from 4,000 to 50,000, more preferably from 5,000 to 30,000, and even more preferably from 6,000 to 25,000, in view of improving the elongation and strength of the cured product.
The Mw/Mn of the polycarbonate polymer A1 is preferably from 1.0 to 3.0, more preferably from 1.01 to 2.50, even more preferably from 1.02 to 2.20, and particularly preferably from 1.03 to 2.00, in view of good elongation of the cured product.
The number of carbonate groups per molecule of the polycarbonate polymer A1 is preferably from 2 to 50 on average, and more preferably from 3 to 30, in terms of improving the strength of the cured product.

[Aspect 2]
In the second embodiment, similarly to the first embodiment, the above-mentioned polycarbonate polyol is used as an initiator.
In aspect 2, alkylene oxide and carbon dioxide are addition-polymerized to the hydroxyl groups (active hydrogen-containing groups) of the polycarbonate polyol, which is an initiator, in the presence of a ring-opening polymerization catalyst. This produces a precursor polymer (hereinafter also referred to as "precursor polymer a2") having a copolymer chain (polycarbonate diol chain) consisting of units based on alkylene oxide and units based on carbon dioxide, and terminated with a hydroxyl group. The number of hydroxyl groups in the polycarbonate polyol is the same as the number of active hydrogen-containing groups in the precursor polymer a2.
The precursor polymer a2, or a derivative of the precursor polymer a2 having one or more reactive terminal groups introduced at the terminal thereof, is reacted with a silylating agent to obtain a polycarbonate polymer A2.

In the embodiment 2, the polycarbonate polyol as the initiator is the same as in the embodiment 1. The ring-opening polymerization catalyst is the same as in the embodiment 1.
In embodiment 2, the method of addition-polymerizing an alkylene oxide and carbon dioxide to a hydroxyl group of an initiator in the presence of a ring-opening polymerization catalyst can be, for example, the methods described in JP2009-544801A, U.S. Patent Application Publication No. 2012/0289732, WO2013/034750, JP2011-522091A, and JP2012-500867A.

The arrangement of the alkylene oxide units and units based on carbon dioxide constituting the polycarbonate diol chain of the precursor polymer a2 may be random, block, or a combination of both. The polycarbonate diol chain has at least a structure represented by formula 5. That is, the polycarbonate diol chain contains a carbonate group. In formula 5, -AO- represents a unit in which the alkylene oxide is ring-opened.
-[AO-C(O)O]- Formula 5
In the embodiment 2, the alkylene oxide unit may be of one type or of two or more types.

The Mn of the precursor polymer a2 is preferably from 4,000 to 50,000, more preferably from 5,000 to 30,000, and even more preferably from 6,000 to 25,000.
The Mw/Mn of the precursor polymer a2 is preferably from 1.0 to 3.0, more preferably from 1.01 to 2.50, further preferably from 1.02 to 2.20, and particularly preferably from 1.03 to 2.00.
The precursor polymer a2 may be a solid, and if it is a solid, it is preferably one which becomes liquid when heated to 90° C. When the precursor polymer a2 is a liquid at 25° C., the viscosity of the precursor polymer a2 at 25° C. is preferably 100 to 100,000 mPa·s, more preferably 1,000 to 60,000 mPa·s, and even more preferably 2,800 to 60,000 mPa·s. A viscosity of at least the lower limit of the above range is preferred in that the curable composition is easy to handle, and a viscosity of at most the upper limit of the above range is preferred in that the strength of the cured product is improved.

In the polycarbonate polymer A2, the molar ratio of carbonate groups/alkylene oxide units is preferably from 0.01 to 1.00, and more preferably from 0.02 to 0.50, since the curable composition has a lower viscosity and is therefore easier to handle, and the strength of the cured product is improved.
The Mn of the polycarbonate polymer A2 is preferably from 4,000 to 50,000, more preferably from 5,000 to 30,000, and even more preferably from 6,000 to 25,000, in view of improving the elongation and strength of the cured product.
The Mw/Mn of the polycarbonate polymer A2 is preferably from 1.0 to 3.0, more preferably from 1.01 to 2.50, even more preferably from 1.02 to 2.20, and particularly preferably from 1.03 to 2.00, in view of better elongation of the cured product.
The number of carbonate groups per molecule of the polycarbonate polymer A2 is preferably from 2 to 50 on average, and more preferably from 3 to 30.

[Aspect 3]
In embodiment 3, a polyol containing no carbonate groups is used as the initiator.
The number of hydroxyl groups in the polyol not containing a carbonate group is 2 or more, preferably 2 to 6, more preferably 2 to 4, still more preferably 2 to 3, and particularly preferably 2. As the polyol, an oligomer (polyether polyol) in which an alkylene oxide is added to a polyol can also be used.
Two or more kinds of polyols may be used. When two or more kinds of polyols are used in combination, the average number of hydroxyl groups per molecule is defined as the number of hydroxyl groups of the polyol.
Examples of polyols having two hydroxyl groups include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 1,4-butanediol, 1,6-hexanediol, and low molecular weight polyoxypropylene glycol.
Examples of polyols having three hydroxyl groups include glycerin, trimethylolpropane, trimethylolethane, and low molecular weight polyoxypropylenetriol.
Examples of polyols having four or more hydroxyl groups include sorbitol and pentaerythritol.
The Mn of the polyol containing no carbonate group is preferably less than 300, more preferably from 62 to 250, and even more preferably from 70 to 200, in view of good reactivity with alkylene oxide.
The Mn of the oligomer (polyether polyol) is preferably from 100 to 5,000, more preferably from 150 to 3,000, and even more preferably from 300 to 3,000, in view of good reactivity with alkylene oxide when forming the oligomer.
The Mw/Mn of the oligomer (polyether polyol) is preferably from 1.0 to 3.0, more preferably from 1.01 to 2.50, even more preferably from 1.02 to 2.20, and particularly preferably from 1.03 to 2.00, since the viscosity of the resulting curable composition becomes lower.

In aspect 3, alkylene oxide and carbon dioxide are addition-polymerized to the hydroxyl groups (active hydrogen-containing groups) of the polyol, which is an initiator, in the presence of a ring-opening polymerization catalyst. This produces a precursor polymer (hereinafter also referred to as "precursor polymer a3") having a polycarbonate diol chain consisting of alkylene oxide units and units based on carbon dioxide, and terminated with hydroxyl groups. The number of hydroxyl groups in the polyol used as the initiator is the same as the number of active hydrogen-containing groups in precursor polymer a3.
A polycarbonate polymer A3 is obtained by reacting a precursor polymer a3 or a derivative of the precursor polymer a3 having one or more reactive terminal groups introduced at the terminal thereof with a silylating agent.

In the third embodiment, the ring-opening polymerization catalyst is the same as in the first embodiment.
In the third embodiment, the method of subjecting an alkylene oxide and carbon dioxide to addition polymerization with a hydroxyl group of a polyol as an initiator in the presence of a ring-opening polymerization catalyst is the same as in the second embodiment.

The Mn of the precursor polymer a3 is preferably from 4,000 to 50,000, more preferably from 5,000 to 30,000, and even more preferably from 6,000 to 25,000.
The Mw/Mn of the precursor polymer a3 is preferably from 1.0 to 3.0, more preferably from 1.01 to 2.50, further preferably from 1.02 to 2.20, and particularly preferably from 1.03 to 2.00.
The precursor polymer a3 is preferably a liquid at 25° C., and the viscosity of the precursor polymer a3 at 25° C. is preferably 100 to 100,000 mPa·s, more preferably 1,000 to 80,000 mPa·s, and even more preferably 2,800 to 60,000 mPa·s. If the viscosity is equal to or greater than the lower limit of the above range, this is preferred in that the curable composition is easy to handle, and if the viscosity is equal to or less than the upper limit of the above range, this is preferred in that the strength of the cured product is improved.

In the polycarbonate polymer A3, the molar ratio of carbonate group/alkylene oxide unit is preferably from 0.01 to 1.00, and more preferably from 0.02 to 0.50, since the curable composition has a low viscosity and is therefore easy to handle, and the strength of the cured product is improved.
The Mn of the polycarbonate polymer A3 is preferably from 4,000 to 50,000, more preferably from 5,000 to 30,000, and even more preferably from 6,000 to 25,000, in view of improving the elongation and strength of the cured product.
In order to improve the elongation of the cured product of the polycarbonate polymer A3, Mw/Mn is preferably from 1.0 to 3.0, more preferably from 1.01 to 2.50, further preferably from 1.02 to 2.20, and particularly preferably from 1.03 to 2.00.
The number of carbonate groups per molecule of the polycarbonate polymer A3 is preferably from 2 to 50 on average, and more preferably from 3 to 30, in order to improve the elongation of the cured product.
The carbonate polymer of the present invention is preferably a polycarbonate polymer represented by the following formula 11, which has one or more reactive silicon groups, two or more carbonate groups, and a repeating unit based on alkylene oxide in one molecule and has an Mn of 4,000 to 50,000.
X ¹⁰ _a R ¹⁰ _3-a Si-Q-[(OR ¹¹ ) _n (OR ¹¹ -O-C(O)) _m (OR ² -O-C(O)) _t ]-O-R ²¹ -O-Q-SiX ¹⁰ _a R ¹⁰ _3-a Formula 11
In formula 11, ^X10 represents a hydroxyl group or an alkoxy group having 1 to 3 carbon atoms, ^R10 represents a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent halohydrocarbon group having 1 to 20 carbon atoms, Q represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 6 carbon atoms or -C(O)NH - ^R31- , ^R31 represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 6 carbon atoms with one bond bonded to a silicon atom, ^R11 represents a substituted or unsubstituted divalent hydrocarbon group having 2 to 4 carbon atoms, ^R2 and ^R21 each independently represent a substituted or unsubstituted divalent hydrocarbon group having 3 to 20 carbon atoms, n is an integer from 1 to 900, t is an integer from 0 to 50, m is an integer from 0 to 500, and n+t+m is an integer of 3 or greater. a is an integer of 1 to 3. When a is 1, R ¹⁰ may be the same or different from each other, and when a is 2 or 3, X ¹⁰ may be the same or different from each other.
X ¹⁰ and R ¹⁰ are the same as X ¹⁰ and R ¹⁰ in the above formula 10, and preferred embodiments are also the same.
Q represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 6 carbon atoms, or -C(O)NH - ^R31- . As the substituted or unsubstituted divalent hydrocarbon group having 1 to 6 carbon atoms, a substituted or unsubstituted divalent chain hydrocarbon group having 1 to 6 carbon atoms is preferable, and an unsubstituted divalent chain hydrocarbon group having 1 to 4 carbon atoms is more preferable.
R ³¹ represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 6 carbon atoms, one of the bonds being bonded to a silicon atom. The substituted or unsubstituted divalent hydrocarbon group having 1 to 6 carbon atoms is preferably a substituted or unsubstituted divalent chain hydrocarbon group having 1 to 6 carbon atoms, more preferably an unsubstituted divalent chain hydrocarbon group having 1 to 4 carbon atoms.
(OR ¹¹ ) represents a unit formed by ring-opening of an alkylene oxide. The alkylene oxide is preferably a cyclic ether having 2 to 4 carbon atoms, such as ethylene oxide, propylene oxide, 1,2-butylene oxide, and 2,3-butylene oxide. Propylene oxide is particularly preferred. The arrangement of the alkylene oxide-based unit and the carbon dioxide-based unit may be random, block, or a combination of both.
^R2 and ^R21 are the same as ^R2 in the above formula 2, and preferred embodiments are also the same.
The unit represented by [(OR ¹¹ ) _n (OR ¹¹ -O-C(O)) _m (OR ² -O-C(O)) _t ] is represented by a repeating unit represented by (OR ¹¹ ), a repeating unit represented by (OR ¹¹ -O-C(O)) and a repeating unit represented by (OR ² -O-C(O)), the order of bonding of each repeating unit is not particularly limited, and each repeating unit may be arranged randomly or in a block form.
n is an integer of 1 to 900, t is an integer of 0 to 50, and m is an integer of 0 to 500. n+t+m is preferably an integer of 3 to 900, more preferably 20 to 800, even more preferably 50 to 600, and particularly preferably 60 to 500.
a is an integer of 1 to 3, when a is 1, R ¹⁰ may be the same or different from each other, and when a is 2 or 3, X ¹⁰ may be the same or different from each other. a is preferably 1 or 2, and more preferably 2.
The Mn of the polymer represented by formula 11 is preferably from 4,000 to 50,000, more preferably from 5,000 to 30,000, and even more preferably from 6,000 to 25,000, in view of improving the elongation and strength of the cured product.
In order to obtain a better elongation of the cured product of the polymer represented by formula 11, Mw/Mn is preferably from 1.0 to 3.0, more preferably from 1.01 to 2.50, even more preferably from 1.02 to 2.20, and particularly preferably from 1.03 to 2.00.
The number of carbonate groups per molecule of the polymer represented by formula 11 is preferably from 2 to 50, and more preferably from 3 to 30, on average, in order to improve the elongation of the cured product.

<Curable Composition>
The polycarbonate polymer of the present invention is a polymer useful as a curable material. Examples of the curable material include sealing materials and adhesives. When the polycarbonate polymer of the present invention is used as a curable material, it is usually preferable to use it as a curable composition.
The curable composition contains the polycarbonate polymer of the present embodiment. In general, the curable composition is a composition containing the polycarbonate polymer and a curing catalyst described below.
The content of the polycarbonate polymer relative to the total mass of the curable composition is preferably 3 to 50 mass%, more preferably 5 to 45 mass%, and even more preferably 10 to 40 mass%. When the content of the polycarbonate polymer is within the above range, the strength and elongation of the cured product are superior.
The curable composition may contain one or more of the curing catalysts. When the curable composition contains the curing catalyst, the content is preferably 0.01 to 15.0 parts by mass, and more preferably 0.1 to 10 parts by mass, relative to 100 parts by mass of the polycarbonate polymer. When the content is 0.1 part by mass or more, the curing reaction proceeds sufficiently, and when the content is 20 parts by mass or less, no localized heat generation or foaming occurs during curing, and a good cured product is easily obtained.

[Other ingredients]
The curable composition contains other components in addition to the polycarbonate polymer. Examples of the other components include additives according to the application of the curable composition, such as an organic polymer having no reactive silicon group represented by the above formula 1, a filler, a plasticizer, a thixotropy imparting agent, an antioxidant, an ultraviolet absorber, a light stabilizer, a dehydrating agent, an adhesion imparting agent, an amine compound, an oxygen curing compound, a photocuring compound, and a curing catalyst (silanol condensation catalyst).
Other components include those described in WO 2013/180203, WO 2014/192842, WO 2016/002907, JP 2014-88481 A, JP 2015-10162 A, JP 2015-105293 A, JP 2017-039728 A, JP 2017-214541 A, and the like. Conventionally known components can be used in combination without limitation.
Two or more of each component may be used in combination.

The curable composition may be a one-part type in which all the ingredients, such as the polycarbonate polymer and the additives, are mixed in advance and stored in a sealed state, and then cured by moisture in the air after application. Alternatively, it may be a two-part type in which a base composition containing at least a component having a reactive silicon group and a hardener composition containing at least a curing catalyst are stored separately, and the hardener composition and base composition are mixed before use. One-part curable compositions are preferred because they are easy to apply.

It is preferable that the one-liquid type curable composition does not contain water. It is preferable that the blended components containing water are dehydrated and dried in advance, or that the components are dehydrated under reduced pressure during blending and kneading.
In the two-liquid type curable composition, the curing agent composition may contain water. The base composition is unlikely to gel even if it contains a small amount of water, but from the viewpoint of storage stability, it is preferable to dehydrate and dry the blended components in advance.
In order to improve storage stability, a dehydrating agent may be added to the one-part curable composition or the two-part base composition.

Suitable applications of the curable composition include sealants (e.g., elastic sealants for architecture, sealants for insulating glass, anti-rust and waterproof sealants for glass ends, sealants for the rear surfaces of solar cells, sealants for buildings, sealants for ships, sealants for automobiles, and sealants for roads), electrical insulating materials (insulating coating materials for electric wires and cables), adhesives, and potting materials.
It is particularly suitable for applications requiring excellent strength and elongation, such as sealing materials and adhesives applied outdoors.

The stress (M50) at 50% elongation of the cured product obtained from the curable composition, measured by a tensile test shown in the Examples described later, tends to be 0.5 N/ ^mm2 or more, and further tends to be 0.8 N/ ^mm2 or more. When it is equal to or more than the lower limit, good strength is obtained, and the composition is suitable as a sealant or adhesive.

The maximum cohesive strength of the cured product obtained from the curable composition, measured by a tensile test shown in the Examples described later, tends to be 1.0 N/ ^mm2 or more, and further tends to be 1.2 N/mm2 or ^more . When it is equal to or more than the lower limit, good strength is obtained, and the composition is suitable as a sealant or adhesive.

The maximum elongation of the cured product obtained from the curable composition, as measured by the tensile test shown in the Examples described later, tends to be 175% or more, and even 180% or more. When the maximum elongation is equal to or more than the lower limit, good elongation is obtained, making the product suitable for use as a sealant or adhesive.
The cured product obtained from the curable composition is easily prevented from cracking due to immersion in water due to the hydrophobicity of the cured product, so that the weather resistance measured by the weather resistance test shown in the examples described later is likely to be 400 hours or more, and even more likely to be 500 hours or more. If it is equal to or more than the lower limit, the weather resistance is good and the composition is suitable as a sealant and adhesive, and is particularly suitable as a sealant used outdoors and an adhesive for buildings and vehicles.

The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.
<Measurement and evaluation methods>
[Mn and molecular weight distribution (Mw/Mn)]
Using HLC-8320GPC (product name of Tosoh Corporation) and tetrahydrofuran as a developing solvent, the number average molecular weight (Mn), weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn) calculated as polyoxypropylene diol were determined.
[Copolymer composition ratio of polymer]
The polymer obtained in the synthesis example described later was dissolved in deuterated chloroform to a concentration of 10 wt %, and ¹ H-NMR was measured at a resolution of 400 MHz (JNM-ECZ400SJNM, product name of JEOL Ltd.). From the obtained results, a peak based on a diol unit present in the polycarbonate diol and a peak based on an alkylene oxide unit were identified, and the copolymer composition ratio in the polymer was calculated from the area.

[viscosity]
The viscosity at 25° C. of the precursor polymer obtained in the synthesis example described later was measured using an E-type viscometer VISCOMETER TV-22 (product name of Toki Sangyo Co., Ltd.).
[Number of reactive silicon in polymer (silylation rate)]
In the method of introducing reactive silicon groups by reacting 1-isocyanatepropylmethyldimethoxysilane with the terminal hydroxyl groups of the precursor polymer, the molar ratio of the amount of 1-isocyanatepropylmethyldimethoxysilane charged to the amount of hydroxyl groups of the precursor polymer was defined as the silylation rate.
[Number of carbonate groups per molecule]
The polymer obtained in the synthesis example described later was dissolved in deuterated chloroform containing an internal standard substance, and ^1H -NMR measurement was carried out. The number of carbonate groups per unit weight was calculated from the sum of the area of the proton bonded to the carbon atom adjacent to the carbonate group and the area of the proton of the methyl group bonded to the carbon atom adjacent to the carbonate group, and the area ratio of the proton of the internal standard substance, and further multiplied by Mn determined by GPC to calculate the number of carbonate groups per molecule.
[Carbonate group/alkylene oxide unit molar ratio]
The polymer obtained in the synthesis example described later was dissolved in deuterated chloroform and ¹ H-NMR was measured. The molar ratio of carbonate group/alkylene oxide unit was calculated from the ratio ((Y _{c +} Y cm )/(Y em +Y _cm )) of the sum of the area of the proton bonded to the carbon atom adjacent to the carbonate group (Y _c ) and the area of the proton of the methyl group bonded to the carbon atom adjacent to the carbonate group (Y _cm ), to the sum of the area of the proton of the methyl group bonded to the carbon atom adjacent to _the ether oxygen of the alkylene oxide (Y _em ) and the area of the proton of the methyl group bonded to the carbon atom adjacent to _the carbonate group _.

[State of cured product]
30 g of the curable composition obtained in the examples described below was filled into a mold measuring 300 mm in length, 25 mm in width, and 2 mm in thickness, and cured at 23° C. and 50% humidity for 3 days, and then cured at 50° C. and 65% humidity for 4 days. The presence of bubbles in the obtained cured product was confirmed and evaluated according to the following criteria. If many bubbles are present in the cured product, the correct value cannot be obtained in the tensile test described below.
Good: No air bubbles in the cured product.
Δ: Air bubbles were found in the cured product, and the volume of the air bubbles was less than 10% of the volume of the cured product.
×: Air bubbles were found in the cured product, and the volume of the air bubbles was 10% or more of the volume of the cured product.
[Tensile test]
The curable compositions obtained in the examples described below were filled into a mold measuring 300 mm in length, 25 mm in width, and 2 mm in thickness, and aged for 3 days at 23° C. and 50% humidity, and then aged for 4 days at 50° C. and 65% humidity. The resulting cured products were punched out with a dumbbell mold to obtain test pieces. Using these test pieces, tensile tests were performed at a tensile speed of 500 mm/min to measure the tensile properties of the stress at 50% elongation (M50, unit: N/mm ² ), maximum point cohesive strength (unit: N/mm ² ), and maximum point elongation (unit: %).
[Weather resistance test]
The curable composition obtained in the examples described below was filled into a mold measuring 25 mm in length, 25 mm in width, and 5 mm in thickness, and aged for 3 days at 23° C. and 50% humidity, and then aged for 4 days at 50° C. and 65% humidity. The obtained 2 mm thick cured product was used as a sample and tested according to the evaluation criteria of JIS A1439. Tests were performed using a Sunshine Weather Meter (product name of Suga Test Instruments Co., Ltd.) under conditions of a black panel temperature of 63° C., humidity of 50%, and water spraying for 2 minutes every 120 minutes, and the time until cracks occurred in the sample was measured.

<Synthesis of Polymer>
(Synthesis Example 1: Polymer A1-1)
Into a reactor equipped with a stirrer, a distillate trap, and a pressure regulator, 450 g of 1,4-butanediol (hereinafter referred to as "1,4-BD"), 620 g of 2,2-dimethyl-1,3-propanediol (neopentyl glycol) (hereinafter referred to as "NPG"), 2140 g of diphenyl carbonate (hereinafter referred to as "DPC"), and 50 mg of magnesium acetate tetrahydrate were placed, and the atmosphere in the reaction tube was replaced with nitrogen. The above raw materials were heated and dissolved in an oil bath set to 200°C, and reacted for 30 minutes.
Next, the pressure was lowered to 0.4 KPa over 5 hours and 30 minutes, while removing the distilled phenol and unreacted diol. Next, in order to increase the molecular weight of the polycarbonate diol, the mixture was reacted for 30 minutes at 200°C and 0.4 KPa, and by-products were distilled off. The Mn of the obtained polycarbonate diol was 1,700. From ¹ H-NMR, the peak area at 4.10-4.20 ppm based on 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 two protons bonded to the methylene group of NPG adjacent to the carbonate group were calculated, and from the ratio of these, the copolymerization composition ratio of 1,4-BD/NPG was 54/46 (molar ratio).
Propylene oxide (hereinafter referred to as "PO") was addition-polymerized to the obtained polycarbonate diol using a zinc hexacyanocobaltate complex having a t-butyl alcohol ligand (hereinafter referred to as "TBA-DMC catalyst") as a catalyst to obtain a precursor polymer a1-1.
97 mol % of 1-isocyanatepropylmethyldimethoxysilane based on the amount (mol) of hydroxyl groups that are terminal groups of precursor polymer a1-1 and 50 mass ppm of an organotin compound (U-860, product name of Nitto Kasei Co., Ltd.) based on precursor polymer a1-1 were added. The mixture was heated at 80° C. for 3 hours to react the hydroxyl groups with 1-isocyanatepropylmethyldimethoxysilane until disappearance of the peak based on the isocyanate groups could be confirmed by FT-IR (ATR method, SPECTRUM 100, product name of PerkinElmer Co., Ltd.), thereby obtaining polymer A1-1.
According to the above method, the number of carbonate groups per molecule and the molar ratio of carbonate groups/alkylene oxide units were calculated. The Mn, Mw/Mn, and viscosity of the precursor polymer, as well as the total number of terminal groups of the polymer, Mn, Mw/Mn, silylation rate, the number of carbonate groups per molecule, and the molar ratio of carbonate groups/alkylene oxide units are shown in Table 1. For the following synthesis examples, each value was calculated in the same manner, and the results are shown in Table 1.

(Synthesis Example 2: Polymer A1-2)
A precursor synthetic product a1-2 having an Mn of 11,200 was obtained in the same manner as in Synthesis Example 1. A polymer A1-2 was obtained by reacting the hydroxyl group, which was the terminal group of the precursor polymer a1-2, with 1-isocyanatepropylmethyldimethoxysilane in the same manner as in Synthesis Example 1.

(Synthesis Example 3: Polymer A1-3)
Into a reactor equipped with a stirrer, a distillate trap, and a pressure regulator, 637 g of 1,4-BD, 1033 g of isosorbide (hereinafter referred to as "iSB"), 2331 g of DPC, and 61 mg of magnesium acetate tetrahydrate were placed, and the inside of the reactor was replaced with nitrogen, and then the internal temperature was raised to 160°C to heat and dissolve the contents. Next, the pressure was lowered to 23 kPa over 5 minutes, and then the reaction was carried out for 90 minutes while distilling and removing phenol. Next, the pressure was lowered to 9.3 kPa over 90 minutes, and further lowered to 0.7 kPa over 30 minutes, and then the temperature was raised to 170°C, and the reaction was carried out for 60 minutes while distilling and removing phenol and unreacted diol to obtain a polycarbonate diol.
The Mn of the polycarbonate diol was 800, and the peak area at 4.10-4.20 ppm due to two protons bonded to the methylene group of 1,4-BD adjacent to the carbonate group and the peak area at 4.90-5.05 ppm due to ^one proton bonded to the methyl group of iSB adjacent to the carbonate group were calculated by 1H-NMR. From these ratios, the copolymerization composition ratio of 1,4-BD/iSB was 55/45 (molar ratio).
PO was addition-polymerized to the polycarbonate diol obtained in the same manner as in Synthesis Example 1 to obtain a precursor polymer a1-3.
In the same manner as in Synthesis Example 1, 1-isocyanatepropylmethyldimethoxysilane was reacted with the hydroxyl group, which was the terminal group of the precursor polymer a1-3, to obtain a polymer A1-3.

(Synthesis Example 4: Polymer A1-4)
A polycarbonate diol was obtained by reaction in the same manner as in Synthesis Example 1, except that 433 g of 1,10-decanediol (hereinafter referred to as "1,10-DD"), 773 g of 1,4-BD, 1794 g of DPC, and 4.7 mL of an aqueous solution of magnesium acetate tetrahydrate (concentration: 8.4 g/L, magnesium acetate tetrahydrate: 40 mg) were placed in a reactor equipped with a stirrer, a distillation trap, and a pressure regulator.
The Mn of the polycarbonate diol was 2,000. From ¹ H-NMR, the peak area at 4.10-4.20 ppm due to two protons bonded to the methylene group of 1,4-BD adjacent to the carbonate group and the peak area at 4.00-4.05 ppm due to two protons bonded to the methyl group of 1,10-DD adjacent to the carbonate group were calculated, and from the ratio of these areas, the copolymerization composition ratio of 1,4-BD/1,10-DD was 47/53 (molar ratio).
PO was addition-polymerized to the polycarbonate diol obtained in the same manner as in Synthesis Example 1 to obtain a precursor polymer a1-4.
In the same manner as in Synthesis Example 1, 1-isocyanatepropylmethyldimethoxysilane was reacted with the hydroxyl group, which was the terminal group of the precursor polymer a1-4, to obtain a polymer A1-4.

(Synthesis Example 5: Polymer A1-5)
Into a reactor equipped with a stirrer, a distillate trap, and a pressure regulator, 830 g of 1,6-hexanediol (hereinafter referred to as "1,6-HD"), 771 g of diethyl carbonate, and 0.05 g of tetrabutoxytitanium were placed, and the inside of the reactor was replaced with nitrogen. The temperature was gradually raised to 190°C under a nitrogen stream, and when the temperature at the top of the distillation column reached 50°C or less, the pressure was gradually reduced to 1.3 KPa while keeping the reaction temperature at 190°C, and a polycarbonate diol consisting of 1,6-HD was obtained. The Mn of the obtained polycarbonate diol was 2,000.
PO was addition-polymerized to the polycarbonate diol obtained in the same manner as in Synthesis Example 1 to obtain a precursor polymer a1-5.
The precursor polymer a1-5 was heated at 80° C. for 3 hours to make it liquid, and then, in the same manner as in Synthesis Example 1, the hydroxyl groups, which were the terminal groups of the precursor polymer a1-5, were reacted with 1-isocyanatepropylmethyldimethoxysilane to obtain a polymer A1-5.

(Synthesis Example 6: Polymer A1-6)
Polypropylene glycol (hereinafter referred to as "PPG") with Mn 1,000 was placed in a reactor, and the gas phase in the reactor was replaced with carbon dioxide while the reactor was connected to a carbon dioxide cylinder. Next, while the reactor was constantly pressurized with carbon dioxide to 2.0 MPa, PO and carbon dioxide were addition-polymerized using the cobalt complex described in paragraphs [0434] to [0436] of JP2015-28182A. The Mn of the obtained polycarbonate diol was 2,100. PO was addition-polymerized to the obtained polycarbonate diol using TBA-DMC catalyst to obtain a precursor polymer a1-6.
Next, in the same manner as in Synthesis Example 1, the hydroxyl groups as the terminal groups of the precursor polymer a1-6 were reacted with 1-isocyanatepropylmethyldimethoxysilane to obtain a polymer A1-6.

(Synthesis Example 7: Polymer A2-1)
Into a reactor equipped with a stirrer, a distillate trap, and a pressure regulator, 637 g of 1,4-BD, 1033 g of iSB, 2331 g of DPC, and 61 mg of magnesium acetate tetrahydrate were placed, and the inside of the reactor was replaced with nitrogen, and then the inside temperature was raised to 160° C. to heat and dissolve the contents. Next, the pressure was lowered to 23 kPa over 5 minutes, and then the reaction was carried out for 90 minutes while distilling and removing phenol. Next, the pressure was lowered to 9.3 kPa over 90 minutes, and further lowered to 0.7 kPa over 30 minutes, and then the temperature was raised to 170° C., and the reaction was carried out for 60 minutes while distilling and removing phenol and unreacted diol to obtain a polycarbonate diol.
The Mn of the polycarbonate diol was 800, and the copolymer composition ratio of 1,4-BD/iSB calculated in the same manner as in Synthesis Example 3 was 55/45 (molar ratio).
The polycarbonate diol was placed in a reactor, and the gas phase in the reactor was replaced with carbon dioxide while the reactor was connected to a carbon dioxide cylinder. Next, while the reactor was constantly pressurized with carbon dioxide to 1.5 MPa, PO and carbon dioxide were addition-polymerized using TBA-DMC catalyst and tetrahydrofuran as a solvent, and after polymerization, tetrahydrofuran was degassed and removed to obtain a polycarbonate diol, which is a precursor polymer a2-1.
In the same manner as in Synthesis Example 1, 1-isocyanatepropylmethyldimethoxysilane was reacted with the hydroxyl group, which was the terminal group of the precursor polymer a2-1, to obtain a polymer A2-1.

(Synthesis Example 8: Polymer A3-1)
A PPG having Mn of 1,000 was placed in a reactor, and the gas phase in the reactor was replaced with carbon dioxide while the reactor was connected to a carbon dioxide cylinder. Next, while the reactor was constantly pressurized with carbon dioxide to 1.5 MPa, PO and carbon dioxide were addition-polymerized using a TBA-DMC catalyst to obtain a polycarbonate diol, which was a precursor polymer a3-1.
In the same manner as in Synthesis Example 1, 1-isocyanatepropylmethyldimethoxysilane was reacted with the hydroxyl group, which was the terminal group of the precursor polymer a3-1, to obtain a polymer A3-1.

(Synthesis Example 9: Polymer C1)
A precursor polymer c1 was obtained by addition polymerization of PO to the PPG in the same manner as in obtaining precursor polymer a1-1 in Synthesis Example 1, except that the polycarbonate diol having an Mn of 1,700 in Synthesis Example 1 was replaced with a PPG having an Mn of 1,000. A polymer C1 was obtained by reacting the hydroxyl group, which was the terminal group of precursor polymer c1, with 1-isocyanatepropylmethyldimethoxysilane in the same manner as in Synthesis Example 1, except that the precursor polymer a1-1 in Synthesis Example 1 was replaced with precursor polymer c1.
(Synthesis Example 10: Polymer C2)
The hydroxyl groups of the polycarbonate diol having Mn of 1,700 produced as the raw material of the precursor polymer a1-1 in Synthesis Example 1 were reacted with 1-isocyanatepropylmethyldimethoxysilane in the same manner as in Synthesis Example 1 to obtain a polymer C2.

<Preparation of Curable Composition>
(Examples 1 to 8)
Examples 1 to 6 are working examples, and Examples 7 and 8 are comparative examples.
Polymers A1-1, A1-3, A1-4, A1-5, A1-6, A3-1, C1 and C2 obtained in Synthesis Examples 1, 3 to 6 and 8 to 10 and Additive 1 having a composition (unit: parts by mass) shown in Table 2 were used and mixed in a composition shown in Table 3 to prepare curable compositions.
The cured product of the curable composition was measured for M50, maximum cohesive strength, and maximum elongation by the above-mentioned methods. The moldability and weather resistance were also evaluated by the above-mentioned methods. The results are shown in Table 3.

<Other ingredients>
The additives listed in Table 2 are as follows:
DINP: Diisononyl phthalate, Sanso Cizer DINP, a New Japan Chemical Co., Ltd. product name.
Whiten SB: Heavy calcium carbonate, product name of Shiraishi Kogyo Co., Ltd.
CCR: Colloidal calcium carbonate, white gloss CCR, Shiraishi Kogyo Co., Ltd. product name.
Disparlon #6500: hydrogenated castor oil-based thixotropic agent, product name of Kusumoto Chemicals Co., Ltd.
KBM-1003: Vinyltrimethoxysilane, product name of Shin-Etsu Chemical Co., Ltd.
KBM-403: 3-glycidyloxypropyltrimethoxysilane, product name of Shin-Etsu Chemical Co., Ltd.
KBM-603: 3-(2-aminoethylamino)propyltrimethoxysilane, product name of Shin-Etsu Chemical Co., Ltd.
TINUVIN 326: Benzotriazole-based ultraviolet absorber, product name of BASF.
IRGANOX 1010: hindered phenol-based antioxidant, product name of BASF.
U-220H: Dibutyltin bis(acetylacetonate), product name of Nitto Kasei Co., Ltd.

Examples 1, 2, 5, 6 and 7 have approximately the same M50 of the cured products.
Example 1, which used a polymer containing a carbonate group, had improved maximum point cohesion and maximum point elongation compared to Example 7, which used a polymer not containing a carbonate group. Weather resistance was the same. Example 2, which used a polymer containing a carbonate group, had the same maximum point cohesion and improved maximum point elongation compared to Example 7. Weather resistance was also improved. Example 5, which used a polymer containing a carbonate group, had improved maximum point elongation compared to Example 7. Example 6, which used a polymer containing a carbonate group, had improved maximum point cohesion and maximum point elongation compared to Example 7.
In Examples 3 and 4, in which a polymer containing a carbonate group was used, the M50, maximum point cohesive strength and maximum point elongation of the cured product were improved as compared to Example 7.
In Example 8, which used a polymer not containing units based on alkylene oxide, the moldability of the curable composition was poor, and the cured product was not evaluated.

Claims (15)

A polycarbonate polymer having a number average molecular weight of 4,000 to 50,000 and represented by the following formula 11, which has a reactive silicon group represented by the following formula 11A, three or more carbonate groups, and a unit based on alkylene oxide in one molecule (however, excluding a copolycarbonate which contains a repeating unit A represented by the following formula (A) and a repeating unit B represented by the following formula (B), and in which the molar ratio of the repeating unit A to the repeating unit B is 9:1 to 1:9) .
-SiX ¹⁰ _a R ¹⁰ _3-a Formula 11A
In formula 11A, X ¹⁰ represents a hydroxyl group or an alkoxy group having 1 to 3 carbon atoms, R ¹⁰ represents a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent halohydrocarbon group having 1 to 20 carbon atoms, and a is an integer from 1 to 3. When a is 1, R ¹⁰ may be the same or different from each other, and when a is 2 or 3, X ¹⁰ may be the same or different from each other.
X ¹⁰ _a R ¹⁰ _3-a Si-Q-[(OR ¹¹ ) _n (OR ¹¹ -O-C(O)) _m (OR ² -O-C(O)) _t ]-O-R ²¹ -O-Q-SiX ¹⁰ _a R ¹⁰ _3-a Formula 11
In formula 11, Q represents -C(O)NH- ^R31- , ^R31 represents an unsubstituted divalent hydrocarbon group having 1 to 6 carbon atoms with one bond to a silicon atom, ^OR11 represents a unit based on alkylene oxide, ^R11 represents an alkylene group having 2 to 4 carbon atoms, ^R2 and ^R21 each independently represent a substituted or unsubstituted divalent hydrocarbon group having 3 to 20 carbon atoms, n is an integer from 1 to 900, t is an integer from 0 to 50, m is an integer from 0 to 500, and n+t+m is an integer of 4 or greater, and ^X10 , ^R10 , and a are the same as those in formula 11A.

In formula (A), R ^x is a divalent alicyclic group having 8 to 12 carbon atoms.
In formula (B), R ^y is a divalent group selected from the group consisting of ethylene and propylene, and z is an integer of 4 to 40. The polycarbonate polymer according to claim 1, wherein the repeating units based on alkylene oxide include units based on propylene oxide. The polycarbonate polymer according to claim 1 or 2, in which the carbonate group/alkylene oxide unit ratio, which represents the molar ratio of the carbonate group content to the alkylene oxide-based unit content, is 0.01 to 1. The polycarbonate polymer according to any one of claims 1 to 3, having a molecular weight distribution of 1.0 to 3.0. The polycarbonate polymer according to any one of claims 1 to 4, which is used for a curable material. A curable composition comprising the polycarbonate polymer according to any one of claims 1 to 4 and a curing catalyst. A cured product of the curable composition according to claim 6. The cured product according to claim 7, which is used as a sealing material. The cured product according to claim 7, which is used as an adhesive. 10. A method for producing the polycarbonate polymer of claim 1, comprising:
A precursor polymer in which X ¹⁰ _a R ¹⁰ _3-a Si-Q—O— in the formula 11 is replaced with a hydroxyl group;
a silylating agent having a reactive silicon group represented by formula 11A and a group capable of reacting with a hydroxyl group, The method for producing a polycarbonate polymer according to claim 10, wherein the precursor polymer is obtained by addition polymerization of an alkylene oxide to the hydroxyl groups of a polycarbonate polyol. The method for producing a polycarbonate polymer according to claim 10, wherein the precursor polymer is obtained by addition polymerization of an alkylene oxide and carbon dioxide to the hydroxyl groups of a polycarbonate polyol. The method for producing a polycarbonate polymer according to claim 11 or 12, wherein the polycarbonate polyol is a polycarbonate diol obtained by condensation polymerization of a diol compound represented by the following formula 2 and a carbonate compound represented by the following formula 3:
HO-R ² -OH Formula 2
In formula 2, ^R2 represents a substituted or unsubstituted divalent hydrocarbon group having 3 to 20 carbon atoms.
R ³ -O-C(O)-O-R ⁴ Formula 3
In formula 3, R ³ and R ⁴ are each independently an alkyl group having 1 to 20 carbon atoms or a phenyl group, or R ³ and R ⁴ are bonded to each other to form a ring. The method for producing a polycarbonate polymer according to claim 13, wherein the diol compound is at least one selected from the group consisting of 1,4-butanediol , 1,10 -decanediol , and isosorbide. The method for producing a polycarbonate polymer according to claim 13 or 14, wherein the number average molecular weight of the polycarbonate diol is 250 to 10,000.