JP5717452B2 - Liquid polybutadiene purification method - Google Patents

Description

  The present invention relates to a method for purifying liquid polybutadiene, and more particularly to a method for producing (meth) acryl-modified (hydrogenated) polybutadiene from which odor components are removed.

  Conventionally, liquid polybutadiene is a resin that has excellent water and moisture resistance, chemical resistance, electrical properties (high dielectric strength, low dielectric constant, arc resistance), transparency, and high toughness properties by curing. It is used for various purposes.

  Therefore, it is produced by reacting a compound having an acryloyl group or a methacryloyl group at the hydroxyl terminal of polybutadiene (hydrogenated) (Patent Documents 1 and 2). The ethyl acrylate, methyl methacrylate, and the like used in this reaction remained in the (meth) acryl-modified (hydrogenated) polybutadiene as an odor component.

(Meth) acrylic modified (hydrogenated) polybutadiene is liquid and cannot remove impurities by crystallization, and since it has a high boiling point, it is difficult to purify by distillation. It was known that when the temperature was raised and the removal operation was carried out over time, it became a gel.
Moreover, it is known that an odor component can be removed by bubbling in an aqueous solvent of an N-vinyl polymer (Patent Document 3).

JP 2006-45284 A JP 2007-2111240 A JP 2003-119201 A

  After the production of (meth) acryl-modified (hydrogenated) polybutadiene, it takes a long time to remove odorous components even at high temperature and reduced pressure, and (meth) acryl-modified ( Hydrogenated) polybutadiene is gelled.

  An object of the present invention is to produce (meth) acryl-modified (hydrogenated) polybutadiene from which odor components are removed.

  In order to solve the above problems, the present inventors simply bubbled (meth) acryl-modified (hydrogenated) polybutadiene with reference to the method of JP-A-2003-119201 to remove odor components. Although it was seen, a sufficient effect was not obtained. The method of this publication is expected to have a sufficient stirring effect by bubbling because it is diluted with a solvent, whereas in the case of (meth) acryl-modified (hydrogenated) polybutadiene, there is no solvent and the viscosity is high. It was found that odor components could not be removed efficiently even by simply bubbling. As a result of further diligent research, bubbling under reduced pressure increases the vacuum contact surface, so that odorous components can be removed efficiently and odor-reduced (meth) acryl-modified (hydrogenated) polybutadiene is obtained. It turns out that you can.

That is, the present invention
(1) Formula (I) whose odor component is 0.1% by weight or less

[Wherein P represents the formula (II)

(Wherein the double line portion of the solid line and the dotted line represents a single bond or a double bond) 0 to 100 mol% of a repeating unit represented by the formula (III)

（式中、実線と点線の二重線部分は単結合又は二重結合を表す）で表される繰り返し単位１００〜０モル％を有し、ＧＰＣによる数平均分子量が５００〜１０，０００であるポリブタジエン又は水素添加ポリブタジエン鎖を表し、Ｘ^１及びＸ^２は、それぞれ独立して、酸素原子及び／又は窒素原子を含んでもよいＣ_１〜Ｃ_２０の結合基を表し、Ｙは水素原子、水酸基、カルボキシル基又は（メタ）アクリロイルオキシ基を表し、Ｒ^１は水素原子またはメチル基を表す］で表される（メタ）アクリル変性ポリブタジエン又は水素添加ポリブタジエン、及び、
（２）式（Ｉ）

(Wherein the double line portion of the solid line and the dotted line represents a single bond or a double bond) and has a repeating unit of 100 to 0 mol%, and the number average molecular weight by GPC is 500 to 10,000. Represents a polybutadiene or hydrogenated polybutadiene chain, X ¹ and X ² each independently represent a C _{1 to} C ₂₀ bonding group that may contain an oxygen atom and / or a nitrogen atom, Y represents a hydrogen atom, a hydroxyl group, A (meth) acryl-modified polybutadiene or a hydrogenated polybutadiene represented by a carboxyl group or a (meth) acryloyloxy group, and R ¹ represents a hydrogen atom or a methyl group;
(2) Formula (I)

[P is the formula (II)

(Wherein the double line portion of the solid line and the dotted line represents a single bond or a double bond) 0 to 100 mol% of a repeating unit represented by the formula (III)

(Wherein the double line portion of the solid line and the dotted line represents a single bond or a double bond) and has a repeating unit of 100 to 0 mol%, and the number average molecular weight by GPC is 500 to 10,000. Represents a polybutadiene or hydrogenated polybutadiene chain, X ¹ and X ² each independently represent a C _{1 to} C ₂₀ bonding group that may contain an oxygen atom and / or a nitrogen atom, Y represents a hydrogen atom, a hydroxyl group, Represents a carboxyl group or a (meth) acryl group, and R ¹ represents a hydrogen atom or a methyl group]. After producing a (meth) acryl-modified polybutadiene or hydrogenated polybutadiene polymer represented by The present invention relates to a method for producing (meth) acryl-modified polybutadiene or hydrogenated polybutadiene having a odor component of 0.1% by weight or less, characterized by bubbling. That.

By the production method of the present invention, (meth) acryl-modified (hydrogenated) polybutadiene from which the odor component is removed can be produced, and the odor component can be prevented from scattering when the product of the present invention is handled.
The (meth) acryl-modified (hydrogenated) polybutadiene having an odor component of 0.1% by weight or less obtained by the production method of the present invention can produce a transparent liquid without turbidity. It is also useful as an adhesive and paint for articles that require transparency, and because of its low dielectric constant, it is also a useful material as a high-frequency polymer material such as electronic materials and antenna materials, and it is an odor component. Because there is no, it is environmentally friendly.

  The (meth) acryl-modified (hydrogenated) polybutadiene of the present invention is not particularly limited as long as it has a (meth) acryloyloxy group at least at one end. In the present invention, (meth) acrylic acid means acrylic acid or methacrylic acid. Further, (hydrogenated) polybutadiene means polybutadiene or hydrogenated polybutadiene.

(Polymer represented by formula (I))
In formula (I), X ¹ and X ² each independently represent a C _{1 to} C ₂₀ bonding group that may contain an oxygen atom and / or a nitrogen atom, and R ¹ represents a hydrogen atom or a methyl group. .
The bonding group oxygen atom and / or nitrogen atom may also contain C ₁ -C _20, in particular, linear or branched divalent alkylene group of C ₁ -C ₂₀ having, having an ether bond A divalent C ₂ -C ₂₀ alkylene group having a straight or branched chain, formula (IV)

(In the formula, each of R ^{4 to} R ⁶ independently has a linear or branched divalent C _{1 to} C ₁₀ alkylene group or a C _{1 to} C ₆ alkyl group as a substituent. Or a C _{3 to} C ₈ cycloalkylene group, a C _{1 to} C ₆ alkyl group optionally having a C _{5 to} C ₈ aromatic group, or a complex group thereof). And the group represented.

Examples of the divalent C ₁ -C ₂₀ alkylene group having a straight chain or branched chain include methylene, ethylene, propylene, methylethylene, butylene, 1,2-dimethylethylene, pentylene, 1-methylbutylene, 2-methylbutylene, Hexaethylene, heptaethylene, octaethylene, nonaethylene, decaethylene and the like can be mentioned. As the divalent C ₂ -C ₂₀ alkylene group having a straight chain or branched chain having an ether bond, — (CH ₂ O) _a (CH ₂ ) — [a represents an integer of 1 to 17], — (CH ₂ CH ₂ O) _b (CH ₂ CH ₂ ) — [b represents an integer of 2 to 8], — (CH ₂ CH ₂ CH ₂ O) _c (CH ₂ CH ₂ CH ₂ ) — [c represents an integer of 1 to 5] and the like.

Examples of the divalent C ₁ -C ₁₀ alkylene group having a straight chain or branched chain in the formula (IV) include the same examples as in the specific examples of the formula (I), and a C ₁ -C ₆ alkyl group. As the C _{3 to} C ₈ cycloalkylene group which may have a substituent, cyclopropylene, 2-methylcyclopropylene, cyclobutylene, 2,2-dimethylcyclobutylene, cyclopentylene, 2,3- Examples thereof include dimethylcyclopentylene, cyclohexylene, 1,3,3, -trimethylcyclohexylene, cyclooctylene and the like, and C _{5 to} C ₈ may have a C _{1 to} C ₆ alkyl group as a substituent. Examples of the aromatic group include 1,4-phenylene group and 2-methyl-1,4-phenylene group.

  Examples of the complexed group include methylene-cyclopropylene, methylene-cyclopentylene, methylene-2,3-dimethylcyclopentylene, methylene-1,3,3-trimethylcyclohexylene, ethylene-cyclopropylene, ethylene -Cyclohexylene, ethylene-3,3-dimethylcyclohexylene, methylene-cyclopropylene-methylene, ethylene-cyclohexylene-methylene, hexylene-cyclohexylene-methylene and the like. Further, a group in which these orders are changed may be used.

  As formula (IV), for example

(* Represents a connecting position).

P in the formula (I) is a polybutadiene chain or a hydrogenated polybutadiene chain having the formula (II) and / or the formula (III) as a repeating unit, and is not present when the double line portion of the solid line and the dotted line is a double bond. Hydrogenated polybutadiene, and in the case of a single bond, means hydrogenated polybutadiene.
When the 1,4-bond repeating unit represented by the formula (II) has a double bond, a trans isomer, a cis isomer, or a mixture thereof may exist.

  The ratio of the repeating unit due to the 1,4-bond represented by the formula (II) and the repeating unit due to the 1,2-bond represented by the formula (III) is 0-100 mol%, respectively. ) Is preferably 80% or more, more preferably 85% or more, and more preferably 90% or more according to the measurement by the Morero method. Preferably, it is 95% or more.

  Y in formula (I) may be unsubstituted (hydrogen atom) or may have a substituent, and examples of the substituent include a hydroxyl group, a carboxyl group, a (meth) acryloyloxy group, and the like. (Meth) acryloyloxy groups are preferred.

The number average molecular weight of the (meth) acryl-modified (hydrogenated) polybutadiene of the present invention is usually about 500 to 10,000 and 1000 to 5000 according to the GPC (gel filtration) method using polystyrene as an index. Is preferred.
The value obtained by dividing the weight average molecular weight of the polymer by the number average molecular weight represents the degree of dispersion. The smaller the value of the dispersion, the narrower the dispersion, and the polymer is composed of polymers having relatively close molecular weights. In addition, when the degree of dispersion is high, the dispersion is wide and the mixture is composed of a polymer having a low molecular weight and a polymer having a high molecular weight, so that the strength of the cured product is reduced and the curing temperature is widened. For this reason, in order to obtain a favorable polymer, it is preferable that the degree of dispersion is small. The degree of dispersion of the (meth) acryl-modified (hydrogenated) polybutadiene of the present invention is 1 to 2, preferably 1 to 1.5, and more preferably 1 to 1.3.

  Hydrogenated polybutadiene is produced by reducing the double bond of polybutadiene with hydrogen, and the hydrogenation rate at this time is 80% or more of the total double bonds, preferably 90% or more, and Preferably it is 99% or more, More preferably, it is 99.5%. The remaining double bond can be quantitatively analyzed by addition reaction of iodine (hereinafter referred to as “iodine value”). The iodine value is 100 or less, preferably 50 or less, more preferably 25 or less. More preferably, it is 15 or less.

  The (meth) acryl introduction rate of the (meth) acryl-modified (hydrogenated) polybutadiene is a value expressed as a percentage of the ratio of (meth) acryl groups to all hydroxyl groups after introducing hydroxyl groups at the ends, The (meth) acryl introduction rate of the (meth) acryl-modified hydrogenated polybutadiene of the present invention is 80% or more, preferably 90% or more, and more preferably 95% or more.

(Method for producing (meth) acryl-modified (hydrogenated) polybutadiene represented by formula (I))
The terminal (meth) acryl-modified polybutadiene or terminal (meth) acryl-modified hydrogenated polybutadiene of the present invention can be produced, for example, according to the following method.

  That is, the formula (V)

(In the formula, R ⁷ represents an alkyl group) (meth) acrylate and a polybutadiene having a hydroxyl group at the polymer end or a hydrogenated polybutadiene as a raw material are reacted in the presence or absence of a catalyst. Therefore, it can be manufactured.
The amount of the (meth) acrylate compound used is in the range of 0.2 to 20 times the molar amount of the hydroxyl group of the polybutadiene having a hydroxyl group at the polymer terminal or the hydrogenated polybutadiene.

  The polybutadiene having a hydroxyl group at the polymer terminal or the hydrogenated polybutadiene has a repeating unit represented by the above formula (II) and / or formula (III), and all or part of the polymer terminal has a hydroxyl group. It is modified with a group.

  As a method for producing polybutadiene, for example, (1) a method of polymerizing butadiene in a solution with a Ziegler catalyst, a lithium catalyst or a radical polymerization initiator, and (2) a method of polymerizing butadiene in a solution in the presence of a sodium catalyst. In addition, examples of the method for producing hydrogenated polybutadiene include a method of hydrogenating the polymer having the repeating unit obtained in the above (1) or (2). According to the method (1), a product in which butadiene is mainly polymerized with 1,4-bonds can be obtained. According to the method (2), a product in which butadiene is mainly polymerized with 1,2-bonds. Can be obtained.

Examples of the method for introducing a hydroxyl group into the polymer terminal of polybutadiene or hydrogenated polybutadiene include a method of adding an epoxy compound to a reaction solution obtained by anionic polymerization of butadiene. Examples of the epoxy compound that can be used here include ethylene oxide and propylene oxide.
The reaction of the (meth) acrylate compound with a polybutadiene having a hydroxyl group at the polymer terminal or a hydrogenated polybutadiene is carried out without solvent or in a suitable inert solvent. Solvents used in the reaction include aromatic hydrocarbon solvents such as benzene, toluene and xylene; ester solvents such as methyl acetate, ethyl acetate and n-propyl acetate; N, N-dimethylformamide, N, N-dimethyl Amide solvents such as acetamide and N-methylpyrrolidone; Ether solvents such as diethyl ether, tetrahydrofuran, 1,2-dimethoxyethane and 1,4-dioxane; Nitrile solvents such as acetonitrile and benzonitrile; n-pentane and n -Saturated hydrocarbon solvents such as hexane, cyclohexane and n-heptane; dimethyl sulfoxide; phosphoric acid amide solvents such as hexamethylphosphoramide (HMPT) and hexamethylphosphoroamide (HMPA).
The reaction temperature is usually in the range of 0 ° C. to 200 ° C., preferably room temperature to 150 ° C., and the reaction is usually completed in several minutes to several hours.

(Bubbling under reduced pressure)
After producing (meth) acryl-modified (hydrogenated) polybutadiene as described above, the pressure inside the reaction vessel is reduced to 0.1 to 20 KPa, preferably 0.5 to 10 KPa, and gas is introduced from the bubbling tube introduced into the vessel. And bubbling.
The amount of bubbling is performed by introducing 0.005 to 0.5 times, preferably 0.02 to 0.3 times the amount of gas per minute with respect to the resin capacity.

In order to perform bubbling under reduced pressure, for example, it can be performed as follows.
Immerse the tip of the bubbling tube in the lower part of the liquid resin in the reaction vessel, start the vacuum while stirring the liquid resin, and increase the vacuum contact surface by stirring while generating gas from the tip of the bubbling tube . Similarly, when a rotary evaporator is used, the tip of the bubbling tube is immersed in the lower part of the liquid resin, and the vacuum contact surface is increased by rotating the flask while generating gas.

The gas used for bubbling is not particularly limited as long as it does not react with (meth) acryl-modified (hydrogenated) polybutadiene. Specifically, an inert gas or air can be exemplified. The inert gas means a rare gas such as helium gas or argon gas, carbon dioxide gas, or nitrogen gas. The gas used may be used individually by 1 type, and 2 or more types may be mixed and used for it.
Moreover, oxygen gas may be mixed with the gas used for bubbling. When a radical substance is present in a liquid containing (meth) acryl-modified (hydrogenated) polybutadiene, the radical can be trapped by mixing oxygen gas. Moreover, it is preferable to remove moisture from the gas used for bubbling before use.
The amount to be bubbled is not particularly limited, and an optimum amount can be selected according to the volume of the reaction solution, the size and shape of the reaction apparatus. The size of the bubble in the bubbling is not particularly limited, and the size varies depending on conditions such as the nozzle shape and gas blowing pressure, but it is preferably smaller. The bubbling position may be any position in the reaction solution, but is preferably the lower layer of the reaction solution, and more preferably directly under the stirrer.

(Odor component)
According to the present invention, the odor component contained in the (meth) acryl-modified (hydrogenated) polybutadiene is 0.1% by weight or less.
The odor component is not particularly limited as a substance, and indicates a causative substance that causes humans to feel uncomfortable due to odor when handling (meth) acryl-modified (hydrogenated) polybutadiene.
When (meth) acrylic groups are introduced into a polybutadiene having a terminal hydroxyl group (hydrogenated) by a transesterification reaction, alkyl methacrylic acid or alkyl acrylate is used, so the main odor component is alkyl methacrylate. In addition to esters and alkyl acrylates, there are alkyl alcohols such as methyl alcohol and ethyl alcohol, acrylic acid, methacrylic acid, and the like, which are decomposition products thereof.
The odor component can be measured by gas chromatography using either a packed column or a capillary column, and a capillary column is preferred.

  Hereinafter, the recording material of the present invention will be described in detail with reference to examples, but the present invention is not necessarily limited thereto.

Example 1
Into a 5 L reaction vessel equipped with a pressure reducing valve and a bubbling tube, 3002 g of 1,2-polybutadiene (G-3000 manufactured by Nippon Soda Co., Ltd.) end-hydroxyethylated and 793 g of ethyl acrylate were charged at 115 to 120 ° C. By reacting for 5 hours, terminal acrylic-modified 1,2-polybutadiene was produced. The amount of residual ethyl acrylate in the liquid and the amount of ethanol as a by-product were measured by gas chromatography, and then the inside of the reaction vessel was depressurized by a vacuum pump, and dry air was bubbled through a bubbling tube. Residual amounts of ethyl acrylate and ethanol were measured every hour after the start of decompression. The results are shown in Table 1.

(Examples 2 and 3 and Comparative Example 1)
Similarly, after producing terminal acrylic-modified 1,2-polybutadiene using 1,2-polybutadiene having a terminal hydroxyethylated (G-3000 manufactured by Nippon Soda Co., Ltd.) and ethyl acrylate, the reduced pressure rate or inflow of dry air The amount was changed, and the residual amounts of ethyl acrylate and ethanol were measured. The results are shown in Table 1. In addition, Comparative Example 1 is a case of only decompression.

  In the gas chromatography in which the odor component was measured, the detection limit of ethyl acrylate was 53 ppm, and the detection limit of ethanol was 49 ppm.

Example 4
Into a 5 L reaction vessel equipped with a pressure reducing valve and a bubbling tube, 107.45 g of 1,2-polybutadiene (GI-3000 manufactured by Nippon Soda Co., Ltd.) end-hydroxyethylated and 28.39 g of ethyl acrylate were added, and 1155- The reaction was carried out at 120 ° C. for 5 hours to produce terminal acrylic-modified 1,2-polybutadiene. After measuring the amount of residual ethyl acrylate in the liquid and the amount of ethanol as a by-product by gas chromatography, the inside of the reaction vessel is depressurized by a vacuum pump, and dry air is fed from the bubbling tube at an inflow rate of 60 mL / min. Bubbling. Residual amounts of ethyl acrylate and ethanol were measured. The results are shown in Table 2.

  Ethyl acrylate and ethanol were not detected at the time of measurement 3 hours after the start of decompression.

(Example 5)
In the same manner as in Example 1, 1,2-polybutadiene having a terminal hydroxyethylated (G-3000 manufactured by Nippon Soda Co., Ltd.) and ethyl acrylate were used to produce terminal acrylic-modified 1,2-polybutadiene, and then a pressure reducing valve. Into a 2 L reaction vessel equipped with a bubbling tube, 863 g of the above product was put to reduce the pressure in the reaction vessel, and nitrogen was fed from the bubbling tube at an inflow rate of 200 mL / min for bubbling. Residual amounts of ethyl acrylate and ethanol were measured every hour after the start of decompression. The results are shown in Table 3.

Claims (1)

Odor component is 0.1% by weight or less, formula (I)

[Wherein P represents the formula (II)

(Wherein the double line portion of the solid line and the dotted line represents a single bond or a double bond) 0 to 100 mol% of a repeating unit represented by the formula (III)

(Wherein the double line portion of the solid line and the dotted line represents a single bond or a double bond) and has a repeating unit of 100 to 0 mol%, and the number average molecular weight by GPC is 500 to 10,000. Represents a polybutadiene or hydrogenated polybutadiene chain, X ¹ and X ² each independently represent a C _{1 to} C ₂₀ bonding group that may contain an oxygen atom and / or a nitrogen atom, Y represents a hydrogen atom, a hydroxyl group, A purified product of (meth) acryl-modified polybutadiene or hydrogenated polybutadiene represented by the following formula: a carboxyl group or a (meth) acryloyloxy group, and R ¹ represents a hydrogen atom or a methyl group.