JP7589934B2 - Polymerizable composition, copolymer, method for producing copolymer, and compound - Google Patents

Description

The present invention relates to a polymerizable composition, a copolymer, a method for producing the copolymer, and a compound.

Vinyl ether polymers are known to be thermostimuli responsive and biocompatible, and are therefore expected to be used in medical applications.
On the other hand, radical polymerization is a typical method for synthesizing copolymers, but it is difficult to control the arrangement of structural units, and it has been particularly difficult to synthesize copolymers with high alternation. For example, it has been reported that an alternating copolymer can be obtained by radically polymerizing maleic anhydride or maleimide together with 2-chloroethyl vinyl ether and 4-hydroxybutyl vinyl ether (Non-Patent Documents 1 and 2), but when maleic anhydride or maleimide is used as a copolymer with a vinyl ether monomer, a segment in which structural units derived from maleic anhydride or structural units derived from maleimide are continuous may be generated, and the alternation of the structural units is insufficient.

In recent years, the inventors have found through their research that when diethyl fumarate is radically polymerized together with 3-[2-[2-(vinyloxy)ethoxy]ethoxy]-1-propyne, the alternation of structural units derived from vinyl ether monomers in the copolymer is improved, but further improvement of the alternation of structural units derived from vinyl ether monomers is desired.

Macromolecules, 1, 482-488 (1968) Macromol. Chem. Phys. , 200(5), 1005-1013 (1999)

The objective of the present invention is to provide a copolymer that has structural units derived from vinyl ether monomers and has a high degree of alternation of the structural units.

As a result of intensive research, the present inventors have unexpectedly found that by copolymerizing a vinyl ether monomer having an ethynyl group and an oxyalkylene group in the molecule with a specific fumarate monomer, a copolymer having structural units derived from the vinyl ether monomer and having a high alternation of the structural units can be obtained, even though the vinyl ether monomer has an ethynyl group in the molecule, and thus completed the present invention.

That is, the present invention relates to the following <1> to <9>.
<1> A polymerizable composition containing the following monomers (A-1) and (B-1) (hereinafter also referred to as the “polymerizable composition of the present invention”).
(A-1) A vinyl ether monomer having an ethynyl group and an oxyalkylene group in the molecule. (B-1) A monomer represented by the following formula (1-1):

[In formula (1-1),
R ¹ represents a linear or branched alkyl group having 1 to 6 carbon atoms;
^R2 represents a single bond or a linear or branched alkanediyl group having 1 to 6 carbon atoms;
R ³ represents *-C≡C-R ⁴ (R ⁴ represents a protecting group for an ethynyl group, and * represents a bond).

<2> The polymerizable composition according to <1>, wherein the monomer (A-1) is a monomer represented by the following formula (2-1):

[In formula (2-1),
^R5 represents a linear or branched alkanediyl group having 1 to 5 carbon atoms;
^R6 represents a single bond or a linear or branched alkanediyl group having 1 to 5 carbon atoms;
and p is an integer from 1 to 12.

<3> A copolymer having the following structural units (A-2) and (B-2) (hereinafter also referred to as the “copolymer of the present invention”).
(A-2) A structural unit derived from a vinyl ether monomer having an ethynyl group and an oxyalkylene group in the molecule. (B-2) A structural unit represented by the following formula (1-2):

[In the formula (1-2),
R ¹ represents a linear or branched alkyl group having 1 to 6 carbon atoms;
^R2 represents a single bond or a linear or branched alkanediyl group having 1 to 6 carbon atoms;
R ⁷ represents *-C≡C-R ⁸ (R ⁸ represents a hydrogen atom or a protecting group for an ethynyl group, and * represents a bond).

<4> The copolymer according to <3>, in which the structural unit (A-2) is a structural unit represented by the following formula (2-2):

[In formula (2-2),
^R5 represents a linear or branched alkanediyl group having 1 to 5 carbon atoms;
^R6 represents a single bond or a linear or branched alkanediyl group having 1 to 5 carbon atoms;
and p is an integer from 1 to 12.

<5> The copolymer according to <3> or <4>, which is an alternating copolymer.

<6> A method for producing a copolymer, comprising a polymerization step of polymerizing the above-mentioned monomer (A-1) and the above-mentioned monomer (B-1) (hereinafter also referred to as the "production method of the present invention").
<7> The method according to <6>, wherein the polymerization is reversible addition-fragmentation chain transfer polymerization (hereinafter, also referred to as "RAFT polymerization").

<8> A compound represented by the above formula (1-1) (hereinafter also referred to as "the compound of the present invention").
<9> The compound according to <8>, wherein R ⁴ is a trialkylsilyl group having a total of 3 to 12 carbon atoms.

According to the polymerizable composition of the present invention and the production method of the present invention, it is possible to obtain a copolymer having structural units derived from vinyl ether monomers, in which the structural units have a high degree of alternation and a narrow dispersity (narrow molecular weight distribution).
Therefore, the copolymer of the present invention has structural units derived from vinyl ether monomers and has a high degree of alternation of the structural units.
The compound of the present invention is useful as a production intermediate for the copolymer of the present invention.

FIG. 2 shows the ¹ H-NMR spectrum of ETPFA obtained in Example 1. FIG. 2 shows the ¹³ C-NMR spectrum of ETPFA obtained in Example 1. FIG. 1 shows the ¹ H-NMR spectrum of the copolymer obtained in Example 2. FIG. 2 shows the MS spectrum of the copolymer obtained in Example 2.

[Polymerizable composition]
The polymerizable composition of the present invention contains the following monomers (A-1) and (B-1).
(A-1) A vinyl ether monomer having an ethynyl group and an oxyalkylene group in the molecule. (B-1) A monomer represented by the following formula (1-1):

[In formula (1-1),
R ¹ represents a linear or branched alkyl group having 1 to 6 carbon atoms;
^R2 represents a single bond or a linear or branched alkanediyl group having 1 to 6 carbon atoms;
R ³ represents *-C≡C-R ⁴ (R ⁴ represents a protecting group for an ethynyl group, and * represents a bond).

(Monomer (A-1))
Monomer (A-1) is a vinyl ether monomer having an ethynyl group and an oxyalkylene group in the molecule. Although monomer (A-1) has an ethynyl group in the molecule, even when this ethynyl group is not protected and is copolymerized with monomer (B-1), a copolymer having a high degree of alternation of structural units derived from monomer (A-1) is obtained.
As the monomer (A-1), a monomer represented by the following formula (2-1) is preferred from the viewpoints of alternation of structural units, ease of production of the copolymer, ready availability of monomer raw materials, ease of monomer synthesis, and the like.

[In formula (2-1),
^R5 represents a linear or branched alkanediyl group having 1 to 5 carbon atoms;
^R6 represents a single bond or a linear or branched alkanediyl group having 1 to 5 carbon atoms;
and p is an integer from 1 to 12.

In formula (2-1), the alkanediyl group represented by R ⁵ preferably has 1 to 4 carbon atoms, more preferably 2 or 3 carbon atoms, and particularly preferably 2 carbon atoms.
Examples of the alkanediyl group represented by ^R5 include a methane-1,1-diyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-1,3-diyl group, a propane-2,2-diyl group, a butane-1,2-diyl group, a butane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, etc. Among these, the alkanediyl group represented by ^R5 is preferably an ethane-1,2-diyl group or a propane-1,2-diyl group, and more preferably an ethane-1,2-diyl group.

R ⁶ represents a single bond or a linear or branched alkanediyl group having 1 to 5 carbon atoms, preferably a linear or branched alkanediyl group having 1 to 5 carbon atoms.
The number of carbon atoms of the alkanediyl group represented by ^R6 is preferably 1 to 3, and particularly preferably 1. Examples of the alkanediyl group represented by ^R6 include the same alkanediyl groups as those represented by ^R5 above, with a methane-1,1-diyl group being preferred.

p is preferably an integer of 1 to 8, more preferably an integer of 1 to 5, still more preferably an integer of 1 to 3, and particularly preferably 2. When p is an integer of 2 to 12, p ^R5s may be the same or different.

Specific examples of monomer (A-1) include 3-[2-[2-(vinyloxy)ethoxy]ethoxy]-1-propyne, 1-(ethenyloxy)-4-(2-propynyloxy)butane, 3-[2-(ethenyloxy)ethoxy]-1-propyne, 3-[(ethenyloxy)methoxy]-1-propyne, 4-ethenyloxy-1-butyne, and 5-ethenyloxy-1-pentyne. These may be used alone or in combination of two or more.

The content of monomer (A-1) is preferably 40 mol% or more, more preferably 42.5 mol% or more, even more preferably 45 mol% or more, and particularly preferably 48 mol% or more, based on the total amount of monomers, from the viewpoint of alternation of structural units, functional expression, etc., and is preferably 60 mol% or less, more preferably 57.5 mol% or less, even more preferably 55 mol% or less, and particularly preferably 52 mol% or less, based on the total amount of monomers, from the viewpoint of alternation of structural units, functional expression, etc. Specific ranges are preferably 40 mol% to 60 mol%, more preferably 42.5 mol% to 57.5 mol%, even more preferably 45 mol% to 55 mol%, and particularly preferably 48 mol% to 52 mol%.

(Monomer (B-1))
The monomer (B-1) is a fumaric acid ester represented by the above formula (1-1).
In formula (1-1), R ¹ represents a linear or branched alkyl group having 1 to 6 carbon atoms.
The number of carbon atoms of the alkyl group represented by R ¹ is preferably 1 to 4, more preferably 1 or 2, from the viewpoints of alternation of structural units, ease of availability of monomer raw materials, ease of monomer synthesis, etc. Examples of the alkyl group represented by ^{R 1} include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, etc. Among these, a methyl group and an ethyl group are preferred from the viewpoints of alternation of structural units, ease of availability of monomer raw materials, ease of monomer synthesis, etc.

^R2 represents a single bond or a linear or branched alkanediyl group having 1 to 6 carbon atoms. From the viewpoints of alternation of structural units, ease of availability of monomer raw materials, ease of monomer synthesis, and the like, a linear or branched alkanediyl group having 1 to 6 carbon atoms is preferred.
From the viewpoints of alternation of structural units, ease of availability of monomer raw materials, ease of monomer synthesis, etc., the number of carbon atoms of the alkanediyl group represented by ^R2 is preferably 1 to 3, and particularly preferably 1. Examples of the alkanediyl group represented by ^R2 include the same alkanediyl group represented by ^R5 above, but from the viewpoints of alternation of structural units, ease of availability of monomer raw materials, ease of monomer synthesis, etc., a methane-1,1-diyl group is preferred.

In formula (1-1), R ³ represents *-C≡C-R ⁴ , and R ⁴ represents a protecting group for an ethynyl group.
The ethynyl-protecting group represented by ^R4 may be any group capable of protecting an ethynyl group, and examples thereof include a trialkylsilyl group, a diarylalkylsilyl group (diphenylmethylsilyl group, etc.), a triarylsilyl group, etc. From the viewpoints of availability, ease of synthesis, etc., a trialkylsilyl group is preferred.
From the viewpoints of availability, ease of synthesis, etc., the total number of carbon atoms in the trialkylsilyl group is preferably 3 to 12, more preferably 3 to 9, and particularly preferably 3 to 6. The alkyl groups contained in the trialkylsilyl group may be linear or branched and may be the same or different.
Examples of the trialkylsilyl group include a trimethylsilyl group, a triethylsilyl group, an isopropyldimethylsilyl group, a tert-butyldimethylsilyl group, a triisopropylsilyl group, and a thexyldimethylsilyl group.

Specific examples of monomer (B-1) include methyl(trimethylsilyl)propargyl fumarate, methyl(triethylsilyl)propargyl fumarate, methyl(triisopropylsilyl)propargyl fumarate, ethyl(trimethylsilyl)propargyl fumarate, ethyl(triethylsilyl)propargyl fumarate, and ethyl(triisopropylsilyl)propargyl fumarate. These may be used alone or in combination of two or more.

The content of monomer (B-1) is preferably 40 mol% or more, more preferably 42.5 mol% or more, even more preferably 45 mol% or more, and particularly preferably 48 mol% or more, based on the total amount of monomers, from the viewpoint of alternation of structural units, functional expression, etc., and is preferably 60 mol% or less, more preferably 57.5 mol% or less, even more preferably 55 mol% or less, and particularly preferably 52 mol% or less, based on the total amount of monomers, from the viewpoint of alternation of structural units, functional expression, etc. Specific ranges are preferably 40 mol% to 60 mol%, more preferably 42.5 mol% to 57.5 mol%, even more preferably 45 mol% to 55 mol%, and particularly preferably 48 mol% to 52 mol%.

The molar ratio of the content of monomer (B-1) to monomer (A-1) [(B-1)/(A-1)] is preferably 0.67 or more, more preferably 0.74 or more, even more preferably 0.82 or more, and particularly preferably 0.92 or more, from the viewpoints of alternation of structural units, functional expression of the polymerizable composition, etc., and is preferably 1.5 or less, more preferably 1.35 or less, even more preferably 1.22 or less, and particularly preferably 1.08 or less, from the viewpoints of alternation of structural units, functional expression of the polymerizable composition, etc. As a specific range, 0.67 or more and 1.5 or less are preferable, 0.74 or more and 1.35 or less are more preferable, 0.82 or more and 1.22 or less are even more preferable, and 0.92 or more and 1.08 or less are particularly preferable.

In addition to the monomers (A-1) and (B-1), the polymerizable composition of the present invention may further contain one or more components selected from a radical polymerization initiator, a chain transfer agent, and a solvent.

Examples of radical polymerization initiators include azo-based polymerization initiators such as azobisisobutyronitrile, azobismethylisobutyrate, azobisdimethylvaleronitrile, and azobiscyanovaleric acid; and peroxide-based polymerization initiators such as benzoyl peroxide and tert-butyl hydroperoxide. These may be used alone or in combination of two or more.

From the viewpoint of controlling the polymerization reaction, the molar ratio of the content of the radical polymerization initiator to the total of the monomers (A-1) and (B-1) [(radical polymerization initiator)/((A-1)+(B-1)] is preferably 0.0001 or more and 0.1 or less, more preferably 0.0005 or more and 0.05 or less, and particularly preferably 0.001 or more and 0.01 or less.

As the chain transfer agent, a chain transfer agent used in RAFT polymerization (hereinafter also referred to as "RAFT agent") is preferable.
The RAFT agent is not particularly limited as long as it is one that can be used in RAFT polymerization. For example, dithiobenzoate-type RAFT agents such as 2-cyanopropan-2-yl benzodithioate and 4-cyano-4-[(thiobenzoyl)sulfanyl]pentanoic acid; 2-hydroxyethyl benzyl trithiocarbonate, 4-[(2-carboxyethylsulfanylthiocarbonyl)sulfanyl]-4-cyanopentanoic acid, 2-{[(2-carboxyethyl)sulfanylthiocarbonyl]sulfanyl}propanoic acid, 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid, 2-cyano-2-[(dodecylsulfanylthiocarbonyl)sulfanyl]sulfanyl trithiocarbonate-type RAFT agents such as 2-[(dodecylsulfanylthiocarbonyl)sulfanyl]propane, S,S-dibenzyltrithiocarbonate, 2-[(dodecylsulfanylthiocarbonyl)sulfanyl]propanoic acid, and methyl 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoate; and dithiocarbamate-type RAFT agents such as 2'-cyanonobutan-2'-yl 4-chloro-3,5-dimethylpyrazole-1-carbodithioate, 2'-cyanonobutan-2'-yl 3,5-dimethylpyrazole-1-carbodithioate, cyanomethyl 3,5-dimethylpyrazole-1-carbodithioate, and cyanomethyl N-methyl-N-phenyldithiocarbamate. In addition to these, for example, Xanthate type RAFT agents such as O-phenyl-S-benzyl xanthate, O-ethyl-S-(1-phenylethyl) xanthate, O-ethyl-S-[2-(ethoxycarbonyl)prop-2-yl] xanthate, O-ethyl-S-(2-cyanoprop-2-yl) xanthate, O-ethyl-S-cyanomethyl xanthate, O-pentafluorophenyl-S-benzyl xanthate, etc. may be mentioned. Note that one of these may be used alone or two or more may be used in combination.
Among these, trithiocarbonate-type RAFT agents are preferred from the viewpoints of reactivity with monomers, polymerization reaction rate, and the like.

From the viewpoint of controlling the polymerization reaction, the molar ratio of the chain transfer agent content to the radical polymerization initiator [(chain transfer agent)/(radical polymerization initiator)] is preferably 0.001 or more and 1.0 or less, more preferably 0.005 or more and 0.5 or less, and particularly preferably 0.01 or more and 0.2 or less.

As the solvent, organic solvents are preferred. For example, aromatic hydrocarbon solvents such as benzene, toluene, xylene, etc.; aliphatic hydrocarbon solvents such as pentane, hexane, etc.; halogenated hydrocarbon solvents such as dichloromethane, dichloroethane, chloroform, etc.; aprotic polar solvents such as N,N-dimethylformamide, dimethylsulfoxide, etc.; cyclic carbonate solvents such as ethylene carbonate, propylene carbonate, etc.; chain carbonate solvents such as diethyl carbonate, dimethyl carbonate, etc.; aliphatic carboxylic acid ester solvents such as methyl formate, methyl acetate, ethyl propionate, etc.; chain ether solvents such as 1,2-diethoxyethane, ethoxymethoxyethane, etc.; cyclic ether solvents such as tetrahydrofuran, 2-methyltetrahydrofuran, etc. may be used. Note that one of these may be used alone, or two or more may be used in combination.

The mass ratio of the solvent to the total of the monomers (A-1) and (B-1) [(solvent)/((A-1)+(B-1)] is preferably 0.1 or more and 100 or less, more preferably 0.5 or more and 50 or less, even more preferably 1.0 or more and 20 or less, and particularly preferably 2.0 or more and 10 or less, from the viewpoints of reaction efficiency, polymerization reaction control, etc.

By using the polymerizable composition of the present invention, it is possible to easily and efficiently produce a copolymer having structural units derived from vinyl ether monomers and having a high degree of alternation of the structural units. It is also possible to produce a copolymer with a narrow dispersion (narrow molecular weight distribution).

[Copolymer]
The copolymer of the present invention has the following structural units (A-2) and (B-2).
(A-2) A structural unit derived from a vinyl ether monomer having an ethynyl group and an oxyalkylene group in the molecule. (B-2) A structural unit represented by the following formula (1-2):

[In the formula (1-2),
R ¹ and R ² are the same as R ¹ and R ² in formula (1-1),
R ⁷ represents *-C≡C-R ⁸ (R ⁸ represents a hydrogen atom or a protecting group for an ethynyl group, and * represents a bond).
The protecting group for the ethynyl group represented by R ⁸ is the same as the protecting group for the ethynyl group represented by R ⁴ .

As the structural unit (A-2), from the viewpoints of alternation of the structural units, ease of production of the copolymer, ready availability of the monomer raw material, ease of monomer synthesis, etc., a structural unit represented by the following formula (2-2) is preferred.

(In formula (2-2), R ⁵ , R ⁶ and p have the same meanings as R ⁵ , R ⁶ and p in formula (2-1).)

The total content of the structural unit (A-2) is preferably 40 mol% or more, more preferably 42.5 mol% or more, even more preferably 45 mol% or more, and particularly preferably 48 mol% or more, based on the total structural units of the copolymer, from the viewpoint of alternation of the structural units, functional expression of the copolymer, etc., and is preferably 60 mol% or less, more preferably 57.5 mol% or less, even more preferably 55 mol% or less, and particularly preferably 52 mol% or less, based on the total structural units of the copolymer, from the viewpoint of alternation of the structural units, functional expression of the copolymer, etc. Specific ranges are preferably 40 mol% to 60 mol%, more preferably 42.5 mol% to 57.5 mol%, even more preferably 45 mol% to 55 mol%, and particularly preferably 48 mol% to 52 mol%.

The total content of the structural unit (B-2) is preferably 40 mol% or more, more preferably 42.5 mol% or more, even more preferably 45 mol% or more, and particularly preferably 48 mol% or more, based on the total structural units of the copolymer, from the viewpoint of alternation of the structural units, functional expression of the copolymer, etc., and is preferably 60 mol% or less, more preferably 57.5 mol% or less, even more preferably 55 mol% or less, and particularly preferably 52 mol% or less, based on the total structural units of the copolymer, from the viewpoint of alternation of the structural units, functional expression of the copolymer, etc. As a specific range, it is preferably 40 mol% or more and 60 mol% or less, more preferably 42.5 mol% or more and 57.5 mol% or less, even more preferably 45 mol% or more and 55 mol% or less, and particularly preferably 48 mol% or more and 52 mol% or less, based on the total structural units of the copolymer.
The content of each structural unit in the copolymer of the present invention can be measured by ¹ H-NMR or the like.

The molar ratio of the content of the structural unit (B-2) to the structural unit (A-2) [(B-2)/(A-2)] is preferably 0.67 or more, more preferably 0.74 or more, even more preferably 0.82 or more, and particularly preferably 0.92 or more, from the viewpoint of the alternation of the structural units and the functional expression of the copolymer, and is preferably 1.5 or less, more preferably 1.35 or less, even more preferably 1.22 or less, and particularly preferably 1.08 or less, from the viewpoint of the alternation of the structural units and the functional expression of the copolymer. Specific ranges are preferably 0.67 or more and 1.5 or less, more preferably 0.74 or more and 1.35 or less, even more preferably 0.82 or more and 1.22 or less, and particularly preferably 0.92 or more and 1.08 or less.

The total content of the segments formed by bonding structural units (A-2) and (B-2) is preferably 80 mol% or more and 100 mol% or less, more preferably 90 mol% or more and 100 mol% or less, and particularly preferably 95 mol% or more and 100 mol% or less, based on the total structural units of the copolymer.

The copolymer of the present invention is preferably an alternating copolymer, and is preferably a non-crosslinked copolymer.
The terminals of the copolymer of the present invention may include a hydrogen atom, a halogen atom, a chain transfer agent residue, or a polymerization initiator residue.

The number average molecular weight (Mn) of the copolymer of the present invention is preferably from 500 to 100,000, and more preferably from 1,000 to 50,000.
The weight average molecular weight (Mw) of the copolymer of the present invention is preferably from 500 to 100,000, and more preferably from 1,000 to 50,000.
The molecular weight distribution (Mw/Mn) is preferably from 1 to 2.5, and more preferably from 1 to 2.
The number average molecular weight, weight average molecular weight and molecular weight distribution may be measured according to the method described in the examples below.

[Method for producing copolymer]
The production method of the present invention is a method for producing a copolymer, which includes a polymerization step of polymerizing the above-mentioned monomer (A-1) and the above-mentioned monomer (B-1). According to the production method of the present invention, the copolymer of the present invention can be produced simply and efficiently.
The monomers (A-1) and (B-1) are the same as those used in the above polymerizable composition.
The monomer (A-1) may be a commercially available product or may be synthesized according to a conventional method. The monomer (A-1) may be treated with a drying agent (e.g., activated alumina) prior to use in the polymerization step. The monomer (A-1) has an ethynyl group in the molecule, and even when the monomer (A-1) is copolymerized with the monomer (B-1) without protecting the ethynyl group, a copolymer having a high alternation of structural units derived from the monomer (A-1) is obtained.

The monomer (B-1) is a novel compound useful as a production intermediate for the copolymer of the present invention.
Monomer (B-1) can be produced by appropriately combining known methods described in Chemistry A European Journal (2011) 17, 13692-13696, Chemistry A European Journal (2014) 20, 14698-14704, etc. For example, it can be produced by protecting the ethynyl group of ethynyl group-containing alcohol (PR-1) using a halotrialkylsilane, a Grignard reagent, etc., and subjecting the resulting protected group-containing alcohol (PR-2) to dehydration condensation with fumaric acid monoester (PR-3).

(Polymerization process)
As the polymerization method in the polymerization step, from the viewpoint of alternation of structural units, living polymerization is preferable, living radical polymerization is more preferable, reversible addition-fragmentation chain transfer polymerization (RAFT polymerization), atom transfer radical polymerization (ATRP polymerization), and nitroxide-mediated radical polymerization (NMP polymerization) are further preferable, and from the viewpoint of narrow dispersion, RAFT polymerization is particularly preferable.

From the viewpoint of reaction efficiency, the polymerization step is preferably carried out in the presence of a radical polymerization initiator and/or a chain transfer agent. Also, from the viewpoint of reaction efficiency, the polymerization step is preferably carried out in the presence of a solvent.
The meanings of various terms, the amounts of each component used, and their ratios in the production method of the present invention are the same as the meanings of various terms, the contents of each component used, and their ratios in the production method of the present invention explained in relation to "the polymerizable composition of the present invention."

The polymerization temperature in the polymerization step is usually 40 to 140°C, but from the viewpoint of reaction efficiency, 60 to 80°C is preferred. The polymerization time is usually 20 minutes to 72 hours, but from the viewpoint of reaction efficiency, 4 to 24 hours is preferred, and 6 to 20 hours is more preferred.

By this polymerization step, it is possible to obtain the copolymer of the present invention in which R ⁸ in formula (1-2) is a protecting group for an ethynyl group.

(Deprotection step)
When obtaining the copolymer of the present invention in which R ⁸ in formula (1-2) is a hydrogen atom, a deprotection step of deprotecting the copolymer obtained in the polymerization step (R ⁸ = ethynyl-protecting group) may be carried out in addition to the above polymerization step.
The protective group may be removed (deprotected) by a known method according to the type of the protective group. For example, when the protective group is a trialkylsilyl group, the protective group can be removed using a fluoride ion source (e.g., tetrabutylammonium fluoride, etc.).
The reaction products obtained in each of the above steps may be purified as necessary.

The copolymer of the present invention which can be produced as described above has structural units derived from vinyl ether monomers and has a high degree of alternation of the structural units.
Therefore, the copolymer of the present invention is useful as a method for alternately arranging two types of ethynyl groups having different reactivities.

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

The analytical conditions in the examples are as follows.
( ^1H -NMR)
Apparatus: Bruker AC-500, internal standard: tetramethylsilane, solvent: CDCl ₃
( ^13C -NMR)
Apparatus: Bruker AC-500, internal standard: tetramethylsilane, solvent: CDCl ₃
(Molecular Weight Measurement)
Measurement method: GPC method, apparatus: EcoSEC HLC-8320GPC manufactured by TOSOH, column: TSKgel-GMH _HR -M manufactured by TOSOH, elution solvent: tetrahydrofuran, standard: polystyrene (MALDI-TOF-MS)
Apparatus: Bruker Autoflex III TOF/TOF, matrix reagent: 1,8,9-trihydroxyanthracene

Example 1 Synthesis of ethyl(trimethylsilyl)propargyl fumarate
Ethyl (trimethylsilyl)propargyl fumarate (hereinafter also referred to as "ETPFA") was synthesized according to the following synthetic route.

33 mL of ethyl magnesium bromide solution (concentration: 2 M, solvent: tetrahydrofuran) was added to 1.3 g of propargyl alcohol, and the mixture was reacted at 10° C. for 25 minutes, after which the temperature in the reaction system was changed to 5° C. Next, 7.3 g of chlorotrimethylsilane was added, and the temperature in the reaction system was changed from 5° C. to 25° C. over 20 minutes. After refluxing for 120 minutes, 27 mL of an aqueous sulfuric acid solution (1 M) was added, and the mixture was reacted at 45° C. for 15 minutes to obtain propargyl alcohol protected with TMS.
50 mL of dichloromethane was added to 670 mg of the TMS-protected propargyl alcohol obtained above, and 500 mg of monoethyl fumarate (hereinafter also referred to as "MEFA") was further added. 430 mg of N,N-dimethyl-4-aminopyridine (DMAP) and 1.0 g of WSC (N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride, manufactured by Tokyo Chemical Industry Co., Ltd.) were added thereto, and the mixture was reacted at room temperature for 24 hours to obtain ETPFA.
The ¹ H-NMR spectrum of the ETPFA obtained in Example 1 is shown in FIG. 1, and the ¹³ C-NMR spectrum is shown in FIG.

Example 2: Synthesis of copolymer
According to the following synthesis route, a copolymer of ETPFA and 3-[2-[2-(vinyloxy)ethoxy]ethoxy]-1-propyne (hereinafter also referred to as "VEEP") was synthesized.

A glass column tube with a diameter of 8 mm was filled with activated alumina (activated alumina for column chromatography, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and VEEP was passed through it for 1 minute. 400 mg of 1,2-dichloroethane was added to 160 mg of this VEEP, and 240 mg of ETPFA obtained in Example 1, 4.6 mg of benzyl 2-hydroxyethyl trithiocarbonate, and 1.7 mg of azobisisobutyronitrile were further added. The tube was immediately connected to a vacuum line, and degassed by repeating the freeze degassing method three times. The tube was sealed under reduced pressure, and the reaction was started at 60°C.
The conversion rate (mol%) and the molecular weight and composition ratio (mol%) of the resulting copolymer were measured 8 hours, 16 hours, and 24 hours after the start of the reaction, and the reaction was terminated at 24 hours to obtain the target copolymer. The results are shown in Table 1. The conversion rate and composition ratio were determined by ¹ H-NMR.
The ¹ H-NMR spectrum of the copolymer obtained in Example 2 is shown in FIG. 3, and the MS spectrum is shown in FIG.

As shown in Table 1, the copolymer obtained in Example 2 had approximately the same number of moles of the structural units derived from VEEP and the structural units derived from ETPFA. In addition, as shown in Figures 3 and 4, the copolymer obtained in Example 2 had a high alternation between the structural units derived from VEEP and the structural units derived from ETPFA.
Thus, it was found that by copolymerizing VEEP and ETPFA, a linear copolymer having structural units derived from VEEP and having a high degree of alternation of the structural units can be obtained.

(Comparative Example 1)
The reaction was carried out for 24 hours at 60° C. in the same manner as in Example 2, except that ETPFA was replaced with ethyl propargyl fumarate (hereinafter also referred to as “EPFA”). A crosslinking reaction due to the double bond and triple bond of EPFA proceeded, and the polymerization product became insoluble in general-purpose organic solvents, and no copolymer with a clear structure was obtained.

(Comparative Example 2)
The reaction was carried out at 60° C. for 24 hours in the same manner as in Example 2, except that ETPFA was replaced with diethyl fumarate (hereinafter also referred to as "DEFA"). The conversion rate (mol %) and the composition ratio (mol %) of the obtained copolymer were measured by ¹ H-NMR. The results are shown in Table 2.

Claims (6)

A polymerizable composition containing the following monomers (A-1) and (B-1).
(A-1) A monomer represented by the following formula (2-1):
(B-1) A monomer represented by the following formula (1-1):

[In formula (2-1),
R5 represents a linear alkanediyl group having 1 to 5 carbon atoms, an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diyl group, a butane-1,2-diyl group, or a butane-1,3-diyl group ^;
R ⁶ represents a single bond, a linear alkanediyl group having 1 to 5 carbon atoms, an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diyl group, a butane-1,2-diyl group, or a butane-1,3-diyl group;
and p is an integer from 1 to 12.

[In formula (1-1),
R ¹ represents a linear alkyl group having 1 to 6 carbon atoms , an isopropyl group, an isobutyl group, a sec-butyl group, or a tert-butyl group ;
^R2 represents a single bond, a linear alkanediyl group having 1 to 6 carbon atoms , an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diyl group, a butane-1,2-diyl group, or a butane-1,3-diyl group ;
R ³ represents *-C≡C-R ⁴ (R ⁴ represents a protecting group for an ethynyl group, and * represents a bond). A copolymer having the following structural units (A-2) and (B-2).
(A-2) A structural unit represented by the following formula (2-2):
(B-2) A structural unit represented by the following formula (1-2):

[In formula (2-2),
R5 represents a linear alkanediyl group having 1 to 5 carbon atoms, an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diyl group, a butane-1,2-diyl group, or a butane-1,3-diyl group ^;
R ⁶ represents a single bond, a linear alkanediyl group having 1 to 5 carbon atoms, an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diyl group, a butane-1,2-diyl group, or a butane-1,3-diyl group;
and p is an integer from 1 to 12.

[In the formula (1-2),
R ¹ represents a linear alkyl group having 1 to 6 carbon atoms , an isopropyl group, an isobutyl group, a sec-butyl group, or a tert-butyl group ;
^R2 represents a single bond, a linear alkanediyl group having 1 to 6 carbon atoms , an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diyl group, a butane-1,2-diyl group, or a butane-1,3-diyl group ;
R ⁷ represents *-C≡C-R ⁸ (R ⁸ represents a hydrogen atom or a protecting group for an ethynyl group, and * represents a bond). The copolymer of claim 2 which is an alternating copolymer. A method for producing a copolymer, comprising a polymerization step of polymerizing the following monomer (A-1) and the following monomer (B-1):
(A-1) A monomer represented by the following formula (2-1):
(B-1) A monomer represented by the following formula (1-1):

[In formula (2-1),
R5 represents a linear alkanediyl group having 1 to 5 carbon atoms, an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diyl group, a butane-1,2-diyl group, or a butane-1,3-diyl group ^;
R ⁶ represents a single bond, a linear alkanediyl group having 1 to 5 carbon atoms, an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diyl group, a butane-1,2-diyl group, or a butane-1,3-diyl group;
and p is an integer from 1 to 12.

[In formula (1-1),
R ¹ represents a linear alkyl group having 1 to 6 carbon atoms , an isopropyl group, an isobutyl group, a sec-butyl group, or a tert-butyl group ;
^R2 represents a single bond, a linear alkanediyl group having 1 to 6 carbon atoms , an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diyl group, a butane-1,2-diyl group, or a butane-1,3-diyl group ;
R ³ represents *-C≡C-R ⁴ (R ⁴ represents a protecting group for an ethynyl group, and * represents a bond). The process according to claim 4 , wherein the polymerization is a reversible addition-fragmentation chain transfer polymerization. A compound represented by the following formula (1-1):

[In formula (1-1),
R ¹ represents a linear alkyl group having 1 to 6 carbon atoms , an isopropyl group, an isobutyl group, a sec-butyl group, or a tert-butyl group ;
^R2 represents a single bond, a linear alkanediyl group having 1 to 6 carbon atoms , an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diyl group, a butane-1,2-diyl group, or a butane-1,3-diyl group ;
R ³ represents *-C≡C-R ⁴ (R ⁴ represents a trialkylsilyl group having a total of 3 to 12 carbon atoms , and * represents a bond).