2,3-dichloro-1,3-butadiene solution, method for producing polymer, and polymer

Abstract

To provide a 2,3-dichloro-1,3-butadiene solution which has storage stability and is excellent in terms of polymerizability during polymer synthesis.SOLUTION: The present invention specifically provides a 2,3-dichloro-1,3-butadiene solution which contains 2,3-dichloro-1,3-butadiene, wherein: the concentration of a polymerization inhibitor in the 2,3-dichloro-1,3-butadiene solution is more than 100 ppm and less than 3,000 ppm; the 2,3-dichloro-1,3-butadiene solution contains n types of solvents; n is an integer of 1 or more; and when δk is the solubility parameter of the solvent k, γk is the hydrogen bond parameter of the solvent k, and Ck is the mass ratio of the solvent k to the total mass of the solvents contained in the 2,3-dichloro-1,3-butadiene solution, formulae (1) and (2) are satisfied.

Description

[Technical Field]

[0001] The present invention relates to a 2,3-dichloro-1,3-butadiene solution, a method for producing a polymer, and a polymer. [Background technology]

[0002] 2,3-Dichloro-1,3-butadiene monomer is used as a raw material in the synthesis of various polymers, but because it has a very high polymerizability, it is difficult to control its storage stability.

[0003] For example, Patent Document 1 discloses a storage-stabilizing composition for 2,3-dichlorobutadiene-1,3, which is obtained by adding at least one of N-nitroso-diphenylamine, N-nitroso-N-cyclohexylaniline, and a nitrous acid chloride compound to 2,3-dichlorobutadiene-1,3 or a mixture of 2,3-dichlorobutadiene-1,3 and an organic solvent. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 59-164835 Summary of the Invention [Problem to be solved by the invention]

[0005] However, according to conventional techniques, it has been difficult to prepare a 2,3-dichloro-1,3-butadiene solution that has storage stability and excellent polymerizability during polymer synthesis.

[0006] The present invention has been made in view of the above circumstances, and provides a 2,3-dichloro-1,3-butadiene solution that has storage stability and excellent polymerizability during polymer synthesis. [Means for solving the problem]

[0007] According to the present invention, there is provided a 2,3-dichloro-1,3-butadiene solution containing 2,3-dichloro-1,3-butadiene, wherein the concentration of a polymerization inhibitor in the 2,3-dichloro-1,3-butadiene solution is more than 100 ppm and less than 3000 ppm, the 2,3-dichloro-1,3-butadiene solution contains n kinds of solvents, n is an integer of 1 or more, and the solubility parameter of the solvent k is δ k , the hydrogen bonding parameter of solvent k is γ k The mass ratio of the solvent k to the total mass of the solvents contained in the 2,3-dichloro-1,3-butadiene solution is C k When the above formula (1) and formula (2) are satisfied, a 2,3-dichloro-1,3-butadiene solution is provided.

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[0008] As a result of intensive investigations, the present inventors have found that a 2,3-dichloro-1,3-butadiene solution having excellent storage stability and excellent polymerizability during polymer synthesis can be obtained by adjusting the solubility parameter δ and hydrogen bonding parameter γ of the entire solvent in the 2,3-dichloro-1,3-butadiene solution so that they fall within specific numerical ranges, and by adjusting the concentration of a polymerization inhibitor so that it falls within specific numerical ranges, thereby completing the present invention.

[0009] Various embodiments of the present invention will be described below as examples, and the embodiments described below can be combined with each other. [1] A 2,3-dichloro-1,3-butadiene solution containing 2,3-dichloro-1,3-butadiene, wherein the concentration of a polymerization inhibitor in the 2,3-dichloro-1,3-butadiene solution is more than 100 ppm and less than 3000 ppm, and the 2,3-dichloro-1,3-butadiene solution contains n kinds of solvents, where n is an integer of 1 or more, and the solubility parameter of the solvent k is δ k , the hydrogen bonding parameter of solvent k is γ kThe mass ratio of the solvent k to the total mass of the solvents contained in the 2,3-dichloro-1,3-butadiene solution is C k When the above formula (1) and (2) are satisfied, the 2,3-dichloro-1,3-butadiene solution is obtained.

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[0010] The 2,3-dichloro-1,3-butadiene solution according to the present invention has excellent storage stability and excellent polymerizability during polymer synthesis. The 2,3-dichloro-1,3-butadiene solution according to the present invention produces little precipitate during storage and has excellent polymerizability, so that problems that occur when a polymer containing 2,3-dichloro-1,3-butadiene monomer units is produced using the 2,3-dichloro-1,3-butadiene solution can be suppressed, production efficiency can be improved, and costs and labor can be reduced. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in detail below by illustrating embodiments of the present invention. The present invention is not limited by these descriptions. The features of the embodiments of the present invention described below can be combined with each other. Furthermore, each feature can be an invention independently.

[0012] 1,2,3-Dichloro-1,3-butadiene solution The 2,3-dichloro-1,3-butadiene solution according to the present invention contains 2,3-dichloro-1,3-butadiene, and the concentration of a polymerization inhibitor in the 2,3-dichloro-1,3-butadiene solution is more than 100 ppm and less than 3000 ppm. The 2,3-dichloro-1,3-butadiene solution contains n kinds of solvents, where n is an integer of 1 or more, and the solubility parameter of the solvent k is δ k , the hydrogen bonding parameter of solvent k is γ k The mass ratio of the solvent k to the total mass of the solvents contained in the 2,3-dichloro-1,3-butadiene solution is C k When this is the case, the following formulas (1) and (2) are satisfied.

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[0013] In a 2,3-dichloro-1,3-butadiene solution according to one embodiment of the present invention, the 2,3-dichloro-1,3-butadiene content per 100 parts by mass of the 2,3-dichloro-1,3-butadiene solution can be 20 parts by mass or more, preferably 50 parts by mass or more. The 2,3-dichloro-1,3-butadiene content may be, for example, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 96, 97, 98, or 99 parts by mass, or may be within a range between any two of the values ​​exemplified here. According to one embodiment of the present invention, even if the 2,3-dichloro-1,3-butadiene content is set to be equal to or greater than the lower limit above and the 2,3-dichloro-1,3-butadiene concentration is high, excellent storage stability and polymerizability during polymer synthesis can be achieved by adjusting the type and blending ratio of the solvent. There are no particular limitations on the method for producing 2,3-dichloro-1,3-butadiene, but as an example, it can be obtained using a by-product from the production of 2-chloro-1,3-butadiene (chloroprene) as a raw material.

[0014] 1.1 Solvent A 2,3-dichloro-1,3-butadiene solution according to one embodiment of the present invention includes a solvent. The solvent can be a liquid in which 2,3-dichloro-1,3-butadiene is soluble. In one embodiment of the present invention, it is preferable that 50 parts by mass or more of 2,3-dichloro-1,3-butadiene can be dissolved in 100 parts by mass of the solvent. The soluble amount of 2,3-dichloro-1,3-butadiene in 100 parts by mass of the solvent may be, for example, 50 parts by mass or more, 55 parts by mass or more, 60 parts by mass or more, 65 parts by mass or more, 70 parts by mass or more, 75 parts by mass or more, 80 parts by mass or more, 85 parts by mass or more, 90 parts by mass or more, 95 parts by mass or more, or 100 parts by mass or more.

[0015] A 2,3-dichloro-1,3-butadiene solution according to one embodiment of the present invention contains n kinds of solvents. n is an integer of 1 or more, and may be 2 or more. n may be, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, or may be within a range between any two of the numerical values ​​exemplified here.

[0016] When a 2,3-dichloro-1,3-butadiene solution contains solvent 1, solvent 2, solvent k, and solvent n, the solubility parameter of solvent k is δ k , the hydrogen bonding parameter of solvent k is γ k , the mass ratio of solvent k to the total mass of solvents contained in the 2,3-dichloro-1,3-butadiene solution is C k The solvent according to the present invention satisfies the formulas (1) and (2).

[0017]

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[0018]

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[0019] Formula (1) indicates that the solubility parameter δ of the entire solvent is greater than 9.0 and less than 10.0. For example, when a 2,3-dichloro-1,3-butadiene solution contains solvent 1, solvent 2, and solvent 3, where solvent 1 has a solubility parameter δ1, solvent 2 has a solubility parameter δ2, and solvent 3 has a solubility parameter δ3, and the mass proportion of solvent 1 relative to the total mass of the solvents contained in the 2,3-dichloro-1,3-butadiene solution is C1, the mass proportion of solvent 2 is C2, and the mass proportion of solvent 3 is C3, the solubility parameter δ of the entire solvent is expressed by the following formula: Solubility parameter of the entire solvent δ = δ1 × C1 + δ2 × C2 + δ3 × C3

[0020] The solubility parameter δ of the entire solvent is greater than 9.0 and less than 10.0, for example, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, and may be within a range between any two of the values ​​exemplified here.

[0021] Formula (2) indicates that the hydrogen bonding parameter γ of the entire solvent is greater than 2.0 and less than 3.0. For example, when a 2,3-dichloro-1,3-butadiene solution contains solvent 1, solvent 2, and solvent 3, and the hydrogen bonding parameter of solvent 1 is γ1, the hydrogen bonding parameter of solvent 2 is γ2, and the hydrogen bonding parameter of solvent 3 is γ3, and the mass proportion of solvent 1 relative to the total mass of the solvents contained in the 2,3-dichloro-1,3-butadiene solution is C1, the mass proportion of solvent 2 is C2, and the mass proportion of solvent 3 is C3, the hydrogen bonding parameter γ of the entire solvent is expressed by the following formula: Hydrogen bond parameter for the entire solvent γ = γ1 × C1 + γ2 × C2 + γ3 × C3

[0022] The hydrogen bonding parameter γ of the entire solvent is greater than 2.0 and less than 3.0, for example, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, and may be within a range between any two of the values ​​exemplified here.

[0023] In this specification, the solubility parameter δ and the hydrogen bonding parameter γ are defined as values ​​obtained by the method described in CM Hansen, Journal of Paint Technology, No. 39, Vol. 505, pp. 104-117 (1967).

[0024] The solubility parameter δ of the entire solvent and the hydrogen bonding parameter γ of the entire solvent can be controlled by adjusting the type and blending ratio of the solvent added. By setting the solubility parameter δ and the hydrogen bonding parameter γ of the entire solvent within the above-mentioned numerical ranges, the compatibility between the solvent and 2,3-dichloro-1,3-butadiene and the dispersion state of 2,3-dichloro-1,3-butadiene in the 2,3-dichloro-1,3-butadiene solution can be appropriately adjusted, and further, by setting the amount of the polymerization inhibitor within a specific numerical range, it is believed that both excellent storage stability and polymerizability can be achieved.

[0025] In the present invention, if the solubility parameter δ of the entire solvent contained in the 2,3-dichloro-1,3-butadiene solution and the hydrogen bond parameter γ of the entire solvent satisfy the above-mentioned numerical ranges, the solvent is k and / or the hydrogen bond parameter γ k The solvent k may contain a solvent k whose value is not within the above range. At least one or more solvents contained in the 2,3-dichloro-1,3-butadiene solution according to one embodiment of the present invention have a solubility parameter δ k and the hydrogen bond parameter γ k It is preferable that the solvent k contains a solvent whose solubility parameter and hydrogen bonding parameter are within the above numerical ranges. The solvent according to one embodiment of the present invention preferably contains 50 mass% or more of a solvent whose solubility parameter and hydrogen bonding parameter are within the above numerical ranges, relative to 100 mass% of the entire solvent. The content of the solvent whose solubility parameter and hydrogen bonding parameter are within the above numerical ranges, relative to 100 mass% of the entire solvent, is, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 mass%, and may be within a range between any two of the numerical values ​​exemplified here. In one embodiment of the present invention, all of the solvents contained in the 2,3-dichloro-1,3-butadiene solution may be solvents whose solubility parameter and hydrogen bonding parameter are within the above numerical ranges.

[0026] The solvent preferably has a low boiling point, for example, from the viewpoint of ease of removal after polymerization using a 2,3-dichloro-1,3-butadiene solution in polymerization. The boiling point may be, for example, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, or 200°C, or may be within a range between any two of the values ​​exemplified here.

[0027] Examples of the solvent include linear alkanes such as 2-methylbutane, amylene, nitrooctane, pentane, hexane, heptane, octane, nonane, and decane; cyclic alkanes such as cyclopentane, cyclohexane, cycloheptane, methylcyclohexane, and ethylcyclohexane; branched alkanes such as 2-methylbutane, isopentane, 2,2,4-trimethylpentane, isohexane, isopentane, and isooctane; aromatic hydrocarbons such as benzene, toluene, ethylbenzene, xylene, mesitylene, tetralin, chlorobenzene, dichlorobenzene, trichlorobenzene, parachlorobenzotrifluoride, anisole, and nitrobenzene; alcohols including methanol, ethanol, normal propanol, isopropanol, normal butanol, isobutanol, tertiary butanol, 2-ethoxyethanol, 2-butoxyethanol, α-terpineol, pentanols, hexanols, benzyl alcohol, and furfuryl alcohol; and diethyl ethers such as methyl ether, ... ethers such as diethyl ether, dipropyl ether, dibutyl ether, tert-butyl methyl ether, cyclopentyl methyl ether, ethylene glycol dimethyl ether, tetrahydrofuran, tetrahydropyran, 1,4-dioxane, 1,3-dioxolane, and morpholine; ketones such as acetone, ethyl methyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl normal amyl ketone, methyl isoamyl ketone, diethyl ketone, cyclohexanone, and isophorone; esters such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, isoamyl acetate, propyl propionate, butyl propionate, ethylene carbonate, dimethyl carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, propiolactone, and γ-butyrolactone; nitrile compounds including acetonitrile, propionitrile, butyronitrile, succinonitrile, capronitrile, adiponitrile, and benzonitrile; dichloromethane, chloroform, 1,The solvent preferably contains at least one, preferably two or more, and more preferably n kinds of alkyl halides such as 2-dichloroethane, trichloroethane, tetrachloroethane, monochloropropane, dichloropropane, trichloropropane, and chlorobutane; vegetable oils such as pine oil, rapeseed oil, palm oil, soybean oil, castor oil, and linseed oil; DMSO, dimethylformamide, and dimethylacetamide. The solvent preferably contains at least one, preferably two or more, and more preferably n kinds of aromatic hydrocarbons, nitrile compounds, and vegetable oils.

[0028] In a 2,3-dichloro-1,3-butadiene solution according to one embodiment of the present invention, the content of the solvent relative to 100 parts by mass of the 2,3-dichloro-1,3-butadiene solution may be, for example, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, or 80 parts by mass, and may be within a range between any two of the numerical values ​​exemplified here.

[0029] 1.2 Polymerization inhibitors The concentration of the polymerization inhibitor in the 2,3-dichloro-1,3-butadiene solution according to the present invention is more than 100 ppm and less than 3000 ppm, and can be 150 to 2800 ppm. The concentration of the polymerization inhibitor can be, for example, 101, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1050, 1100, 1150, 1200, 1250, 1300, 1350, 1400, 1450, 1500, 1550, 1600, 1650, 1700, 1750, 1800, 1850, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300, 3400, 3500, 3600, 3700, 3800, 3900, 4000, 4100, 4200, 4300, 4400, 4500, 5000, 5500, 6000, 6500, 7000, 7500, 8000, 8500, 9000, 9500, 1000, 1050, 110 The preferred concentrations are 50, 1800, 1850, 1900, 1950, 2000, 2050, 2100, 2150, 2200, 2250, 2300, 2350, 2400, 2450, 2500, 2550, 2600, 2650, 2700, 2750, 2800, 2850, 2900, 2950, ​​and 2999 ppm, and may be within a range between any two of the values ​​exemplified here. According to the present invention, by adjusting the solubility parameter δ and hydrogen bonding parameter γ of the entire solvent to fall within a specific numerical range and adjusting the concentration of the polymerization inhibitor, it is possible to suppress the generation of dimers and oligomers during storage and to smoothly carry out polymerization in the polymerization step after storage.

[0030] The amount of the polymerization inhibitor can be controlled by adjusting the amount added during solution preparation or the amount of the polymerization inhibitor used upon completion of the synthesis of 2,3-dichloro-1,3-butadiene. The amount of the polymerization inhibitor can be analyzed by, for example, gas chromatography with mass spectrometry, liquid chromatography, liquid chromatography with mass spectrometry, or nuclear magnetic resonance.

[0031] As the polymerization inhibitor, a phenolic polymerization inhibitor soluble in alkali is preferred from the viewpoint of quickly removing the unnecessary polymerization inhibitor. Specific examples of the phenolic polymerization inhibitor include 4-tert-butylcatechol, 1,3,5-trihydroxybenzene, 2,6-di-t-butyl-4-methylphenol, 2,2-methylenebis(6-t-4-methylphenol), and 4,4-butylenebis(6-t-butyl-3-methylphenol), and it is preferable that the inhibitor contains 4-tert-butylcatechol.

[0032] 1.3 Other The 2,3-dichloro-1,3-butadiene solution according to one embodiment of the present invention may contain components other than 2,3-dichloro-1,3-butadiene, a solvent, and a polymerization inhibitor. For example, the solution may contain chloroprene, isomers produced during chloroprene synthesis, dimers and oligomers of 2,3-dichloro-1,3-butadiene, and water. In one embodiment of the present invention, when the 2,3-dichloro-1,3-butadiene solution is taken as 100% by mass, the content of the other components may be, for example, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 4, 6, 8, 10, 12, 14, 16, 18, or 20% by mass, or may be within a range between any two of the values ​​exemplified here. The 2,3-dichloro-1,3-butadiene solution according to one embodiment of the present invention preferably does not undergo phase separation, and the content of the other components, such as water, is preferably an amount that does not cause phase separation.

[0033] 2. Characteristics of 2,3-dichloro-1,3-butadiene solution The viscosity of the 2,3-dichloro-1,3-butadiene solution according to one embodiment of the present invention after storage at 80° C. for 24 hours is preferably less than 500 mPa·sec, and more preferably less than 100 mPa·sec. The viscosity may be, for example, 50, 100, 150, 200, 250, 300, 350, 400, 450, or 499 mPa·sec, or may be within a range between any two of the values ​​exemplified here.

[0034] The viscosity can be measured by the method described in the Examples. The viscosity can be used as a measure of the amount of dimer, oligomer, or polymer of 2,3-dichloro-1,3-butadiene produced, and can be controlled by suppressing the progress of polymerization of 2,3-dichloro-1,3-butadiene in the 2,3-dichloro-1,3-butadiene solution and suppressing the production of dimer, oligomer, or polymer of 2,3-dichloro-1,3-butadiene.

[0035] It is preferable that the 2,3-dichloro-1,3-butadiene solution according to one embodiment of the present invention does not exhibit the formation of precipitates after storage for 24 hours at 80° C. The precipitates are considered to be derived from dimers, oligomers, and polymers of 2,3-dichloro-1,3-butadiene.

[0036] A 2,3-dichloro-1,3-butadiene solution according to one embodiment of the present invention is washed with 40 parts by mass of a 4 g / L aqueous sodium hydroxide solution, and then polymerized for 8 hours at a polymerization temperature of 40°C while adding a polymerization initiator, V-70 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), at a rate of 50 ppm / hour relative to the 2,3-dichloro-1,3-butadiene. The polymerization rate is preferably 80% or higher. The polymerization rate may be, for example, 80, 85, 90, 95, 96, 97, 98, 99, or 100%, or may be within a range between any two of the values ​​exemplified here. The polymerization rate can be determined by the method described in the Examples.

[0037] The 2,3-dichloro-1,3-butadiene solution according to one embodiment of the present invention is suitable for storage and transportation because it can inhibit the generation of dimers, oligomers, and polymers of 2,3-dichloro-1,3-butadiene during storage. Furthermore, the 2,3-dichloro-1,3-butadiene solution according to one embodiment of the present invention has excellent storage stability and excellent polymerizability during polymer synthesis, and therefore can be suitably used for polymerization, i.e., as a raw material for polymer production. The 2,3-dichloro-1,3-butadiene solution according to one embodiment of the present invention can be used for polymerization after storage and / or transportation, and can be used for storage and / or transportation, as well as for polymerization.

[0038] Furthermore, a method for storing a 2,3-dichloro-1,3-butadiene solution according to one embodiment of the present invention can involve storing the solution at 30°C or below, and the storage period can be 30 days or longer. The storage temperature can be, for example, 0, 5, 10, 15, 20, 25, or 30°C, and can be within a range between any two of the values ​​exemplified herein. The storage period can be, for example, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 300, 400, or 500 days, and can be within a range between any two of the values ​​exemplified herein. For example, a 2,3-dichloro-1,3-butadiene solution according to one embodiment of the present invention can preferably be stably stored for 128 days or more when stored at 10° C., can preferably be stably stored for 64 days or more when stored at 20° C., and can preferably be stably stored for 32 days or more when stored at 30° C. Note that being stably storable may mean that no precipitate is formed during the storage period and that the viscosity is less than 500 mPa sec.

[0039] 3. Polymers A polymer according to one embodiment of the present invention may be a polymer containing 2,3-dichloro-1,3-butadiene monomer units contained in the 2,3-dichloro-1,3-butadiene solution. The polymer may be a homopolymer of 2,3-dichloro-1,3-butadiene. The polymer may contain 2,3-dichloro-1,3-butadiene monomer units and may also contain other monomer units copolymerizable with the 2,3-dichloro-1,3-butadiene monomer units. Examples of other monomer units include chloroprene, (meth)acrylic acid esters (methyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc.), hydroxyalkyl (meth)acrylates (2-hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, etc.), 1-chloro-1,3-butadiene, butadiene, isoprene, unsaturated nitriles, ethylene, styrene, sulfur, etc. The polymer may have a content of 2,3-dichloro-1,3-butadiene monomer units of, for example, 1, 2, 3, 4, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100% by mass relative to 100% by mass of the polymer, and may be within a range between any two of the values ​​exemplified here.

[0040] A method for producing a polymer according to one embodiment of the present invention can include a polymerization step of polymerizing a polymer containing 2,3-dichloro-1,3-butadiene monomer units using 2,3-dichloro-1,3-butadiene contained in a 2,3-dichloro-1,3-butadiene solution as a raw material monomer, with the addition of an initiator, an emulsifier, etc. as necessary. The 2,3-dichloro-1,3-butadiene solution can be used for polymerization as is, or can be used for polymerization after removing unnecessary components such as a polymerization inhibitor. According to the production method according to one embodiment of the present invention, 2,3-dichloro-1,3-butadiene derived from the 2,3-dichloro-1,3-butadiene solution is used, and therefore, unintended dimers, oligomers, and polymers of 2,3-dichloro-1,3-butadiene are reduced, and polymerization efficiency is excellent. [Example]

[0041] The present invention will be described in more detail below based on examples, but the present invention should not be construed as being limited to these examples.

[0042] Example 1 A 2,3-dichloro-1,3-butadiene solution was prepared by adding 2,3-dichloro-1,3-butadiene and a polymerization inhibitor to a solvent consisting of ethylbenzene and acetonitrile, with the ethylbenzene and acetonitrile being mixed in a mass ratio of 0.774:0.226. The 2,3-dichloro-1,3-butadiene content was 50 parts by mass per 100 parts by mass of the 2,3-dichloro-1,3-butadiene solution. 4-tert-butylcatechol (TBC) was used as the polymerization inhibitor, and the polymerization inhibitor concentration in the 2,3-dichloro-1,3-butadiene solution was 1000 ppm. The 2,3-dichloro-1,3-butadiene solution was prepared at room temperature (23°C).

[0043] (Examples 2 to 11, Comparative Examples 1 to 5) A 2,3-dichloro-1,3-butadiene solution was prepared in the same manner as in Example 1, except that the type and blending ratio of the solvent, the content of 2,3-dichloro-1,3-butadiene, and the concentration of the polymerization inhibitor were changed as shown in the table.

[0044] Solubility parameter δk and hydrogen bond parameter γ for each solvent k The values ​​were obtained by the method described in CM Hansen, Journal of Paint Technology, No. 39, Vol. 505, pp. 104-117 (1967).

[0045] The resulting 2,3-dichloro-1,3-butadiene solution was evaluated by the following method. (precipitation occurs) The 2,3-dichloro-1,3-butadiene solution was stored at 80°C for 24 hours, and the presence or absence of precipitation was visually confirmed and evaluated according to the following criteria. ○: No precipitate was observed. ×: Precipitation was observed.

[0046] (polymerizable) A 2,3-dichloro-1,3-butadiene solution was polymerized under the following conditions to produce a polymer. The solution was washed using 40 parts by mass of a 4 g / L aqueous sodium hydroxide solution per 100 parts by mass of the 2,3-dichloro-1,3-butadiene solution, and polymerization was carried out at 40°C while adding V-70 manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. as a polymerization initiator at a rate of 50 ppm per hour relative to the 2,3-dichloro-1,3-butadiene. Eight hours after the start of polymerization, phenothiazine was added as a polymerization inhibitor to terminate the polymerization, and the conversion at that time was determined. ◯: The polymerization rate was 80% or more. ×: The polymerization rate was less than 80%.

[0047] (viscosity) The 2,3-dichloro-1,3-butadiene solution was stored at 80°C for 24 hours, and then the viscosity was measured using a Brookfield viscometer under the following conditions. Measuring equipment: "VISCOMETER TVB-20L" manufactured by Toki Sangyo Co., Ltd. Spindle rotor: 1 (disk-shaped, radius 19 mm x thickness 7 mm) Rotation speed: 30 rpm ○: Viscosity was less than 100 mPa·sec △: Viscosity was 100 mPa·sec or more and less than 500 mPa·sec ×: Viscosity was 500 mPa·sec or more

[0048] [Table 1]

[0049] [Table 2]

Claims

1. A 2,3-dichloro-1,3-butadiene solution containing 2,3-dichloro-1,3-butadiene, The concentration of the polymerization inhibitor in the 2,3-dichloro-1,3-butadiene solution is more than 100 ppm and less than 3000 ppm, The 2,3-dichloro-1,3-butadiene solution contains n kinds of solvents, n is an integer of 1 or more, The solubility parameter of solvent k is δ ｋ , the hydrogen bond parameter of solvent k is γ ｋ The mass ratio of the solvent k to the total mass of the solvents contained in the 2,3-dichloro-1,3-butadiene solution is C ｋ When the above formula (1) and (2) are satisfied, the 2,3-dichloro-1,3-butadiene solution is obtained. [Equation 1] [Equation 2]

2. The 2,3-dichloro-1,3-butadiene solution according to claim 1, wherein the content of 2,3-dichloro-1,3-butadiene per 100 parts by mass of the 2,3-dichloro-1,3-butadiene solution is 50 parts by mass or more.

3. The 2,3-dichloro-1,3-butadiene solution according to claim 1 or 2, which is for at least one of storage, transportation, and reaction.

4. A method for producing a polymer, the method comprising a polymerization step, The production method, wherein the polymerization step is carried out by polymerizing raw material monomers including 2,3-dichloro-1,3-butadiene contained in the 2,3-dichloro-1,3-butadiene solution according to claim 1 or 2 to obtain the polymer.

5. A polymer comprising a monomer unit derived from 2,3-dichloro-1,3-butadiene contained in the 2,3-dichloro-1,3-butadiene solution according to claim 1 or 2.

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