JPH05279404A - Suspension polymerization of styrenic monomer - Google Patents

Abstract

PURPOSE:To prevent attachment of scale and carry out suspension polymerization of a styrenic monomer in high yield by previously applying an addition reaction product of a quinone compound with an amine compound to a part with which a monomer in a polymerizer is brought into contact and carrying out polymerization of the monomer. CONSTITUTION:(A) A1: An aromatic quinone (aromatic ring is preferably benzene, naphthalene or phenanthrene) is subjected to addition reaction with A2: aromatic diamine (aromatic ring is preferably benzene, naphthalene or phenanthrene) in a solvent and then the reaction product is polymerized by anodic oxidation with an oxidizing agent or an electrode to produce a quinone- amine compound and/or its reduction treatment material having >=3000 molecular weight. (B) The addition reaction product obtained in the process A is dissolved or dispersed in an organic solvent to prepare a coating liquid. (C) A part with which a monomer in a polymerizer is brought into contact, e.g. inner wall of the polymerizer is previously heated at preferably 50-90 deg.C and then the coating liquid obtained in the process B is applied to the part and dried to carry out suspension polymerization of a styrenic monomer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for effectively preventing the adhesion of polymer scale to the inner wall of a polymerization vessel, a stirrer, and other portions where the monomer comes into contact in the polymerization of styrene-based monomers.

[0002]

2. Description of the Related Art In a method for producing a polymer by polymerizing monomers in a polymerization vessel, it is known that the polymer adheres to the inner wall surface of the polymerization vessel as a scale. When the polymer scale adheres to the inner wall surface of the polymerization vessel, not only a great amount of labor and time are required to remove the polymer scale,
Various inconveniences occur such as a decrease in the yield of the polymer, a decrease in the temperature rising / cooling ability of the polymerization vessel, and a decrease in quality due to the adhered polymer scale peeling off and mixing with the product polymer.

Conventionally, as a method for preventing the adhesion of the polymer scale to the inner wall surface of the polymerization vessel, for example, a method of applying a polar compound, a dye, a pigment or the like to the inner wall surface (Japanese Patent Publication No. 4).
No. 5-30343, No. 45-30835), and a method of applying an aromatic amine compound (JP-A-51-50887).
No.), a method of applying a reaction product of a phenol compound and an aromatic aldehyde (JP-A-55-54317), and a method of treating the inner wall surface with a treatment liquid containing a titanium compound, a zinc compound, etc. No. 47105) is known. These methods have a certain scale-preventing effect in the case of a general suspension polymerization method in which a vinyl monomer is charged in an aqueous dispersion medium and stirred and polymerized. However, it is difficult to prevent scale adhesion by these methods, especially in a special suspension polymerization method in which suspension droplets are not fragmented and coalesced by gentle stirring.

[0004]

Therefore, the present inventors have proposed a method capable of effectively preventing adhesion of polymer scale during suspension polymerization of styrene-based monomers, especially under mild stirring conditions. As a result of intensive research efforts to find a method in which no scale is generated even in suspension polymerization, the present invention has been accomplished.

[0005]

That is, according to the present invention, an addition reaction product of a quinone compound and an amine compound is applied in advance to the inner wall of the polymerization vessel, a stirrer, and other portions where the monomer comes into contact with the suspension polymerization. The present invention provides a suspension polymerization method of a styrenic monomer, which is characterized by carrying out the method. The addition reaction product of a quinone compound and an amine compound used in the present invention is obtained by subjecting an aromatic quinone and an aromatic diamine to an addition reaction in a solvent, and then polymerizing them by anodic oxidation with an oxidizing agent or an electrode. A quinone-amine compound having a molecular weight of 3000 or more and / or a reduction-treated product of this quinone-amine compound is preferable from the viewpoint of the strength of the coating film.

Examples of the aromatic quinone include benzoquinone, naphthoquinone, phenanthquinone, and 1,2-anthraquinone, and the hydrogen atom of these aromatic rings is a halogen atom such as chlorine, an alkyl group such as a methyl group, or an amino group. Examples thereof include quinone derivatives substituted with an alkoxy group, a hydroxyl group and the like, and these may be used alone or in combination of two or more kinds. As the aromatic ring of the aromatic quinone, a benzene ring, a naphthalene ring and a phenanthrene ring are preferable. Examples of aromatic diamines include phenylenediamine, diaminonaphthalene, diaminoacridine, diaminopyridine, diaminopyrimidine, diaminofluorene, diaminoazobenzene, benzidine, diaminotoluene, and diaminoanthracene. Examples thereof include amine derivatives substituted with a group, an aryl group, an alkoxy group, a halogen atom, a hydroxyl group, a mercapto group, a nitro group and the like, and these may be used alone or in combination of two or more kinds. The aromatic ring of the aromatic diamine is preferably a benzene ring, a naphthalene ring or a phenanthrene ring.

The solvent used for the addition reaction of the aromatic quinone and the aromatic diamine may be a commonly used solvent, preferably tetrahydrofuran, dimethylformamide,
Dimethylacetamide, acetonitrile, acetone, methyl ethyl ketone, methanol, isopropanol, n
-Butanol, ethyl acetate, water etc. are used.

When the addition reaction of aromatic quinone and aromatic diamine is carried out in a solvent, the amount of aromatic quinone is preferably 0.8 to 5 mol per 1 mol of aromatic diamine. If it is less than 0.8 mol, a reaction product of only aromatic diamine is produced, and if it is more than 5 mol, the yield of the addition reaction product is lowered. The reaction between the aromatic quinone and the aromatic diamine starts immediately after mixing them, and the reaction liquid turns black. After that, the polymer addition reaction is promoted by an oxidizing agent or anodic oxidation. When an oxidizing agent such as iron chloride or copper chloride is used, the reaction solution is added to an aqueous solution in which a reducing agent such as sodium bisulfite is dissolved to stop the reaction, and then the precipitate of this aqueous solution is added with methanol, styrene, or the like. After washing, it is dried under reduced pressure. In order to form a film by applying a scale inhibitor composed of the quinone-amine compound and / or a reduction product thereof produced in this manner to each part of the polymerization vessel,
A method of dissolving in an organic solvent and applying with a spray, a brush or the like is adopted.

The organic solvent for dissolving the quinone-amine compound is preferably one having a large dissolving power, a low boiling point, easy drying, a small surface tension and a uniform coating. Examples of the organic solvent having such properties include dimethylformamide, dimethylacetamide, acetone, methylethylketone, acetonitrile, pyridine, and tetrahydrofuran, and among these, dimethylformamide is particularly preferably used. When there is no choice but to select a solvent having a large surface tension, it is preferable to use a solvent having a low surface tension such as n-butanol or ethanol. Also,
The concentration of the scale inhibitor solution is preferably 0.5 to 2% by weight from the viewpoint of coating time and drying time. The amount of the scale inhibitor applied is 0.01 to 5 g / m ² , preferably 0.1 to 1.
It is 0 g / m ² .

When the scale inhibitor solution is applied, it is preferable that the surface to be coated is previously cleaned by a method such as chemical cleaning, and if the surface is heated to 50 to 90 ° C., a strong coating film is obtained. Is obtained and is preferable. The polymerization vessel treated with such a scale inhibitor exhibits a good scale adhesion preventing effect in all polymerization methods including general suspension polymerization of styrene-based monomers, but it is particularly difficult to prevent scale adhesion conventionally. Even in suspension polymerization under mild stirring conditions, good effect of preventing scale adhesion is observed. That is, in the suspension polymerization method, the liquid column of the styrene-based monomer ejected from the nozzle into the aqueous dispersion medium is subjected to regular vibrational disturbance to form a group of monomer droplets having a uniform diameter in the aqueous dispersion medium. In the case where the polymerization method is carried out under a gentle stirring condition in which the droplets do not fragment after coalescence, it was difficult to prevent scale adhesion by the conventional method. Adhesion can be suppressed almost completely.

Examples of the styrenic monomer used in the present invention include styrene, vinyltoluene, chlorostyrene, t-butylstyrene, α-methylstyrene, vinylnaphthalene, and the like, which may be used alone or in admixture of two or more. Used. Also, a mixture with other copolymerizable monomer containing 50% or more of these styrene-based monomers may be used. Other copolymerizable monomers include acrylonitrile, methacrylonitrile, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, vinyl acetate,
Butadiene etc. are mentioned.

The suspending agent used in the polymerization in the present invention is a generally used suspending agent, for example, water-soluble such as partially saponified polyvinyl alcohol, polyvinylpyrrolidone, methylcellulose and polyacrylate. Polymer, calcium triphosphate, sodium pyrophosphate,
Examples include poorly water-soluble inorganic substances such as magnesium oxide, which may be used alone or in admixture of two or more. When a poorly water-soluble inorganic substance is used, suspension stability is improved when an anionic surfactant such as sodium laurate, sodium α-olefin sulfonate, and sodium dodecylbenzene sulfonate is used in combination.

[0013]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the Examples. Production Example 1 (Synthesis of Scale Inhibitor) 60 g of methanol and 6.7 g of tetrahydrofuran were charged into a reaction vessel, 5 g of β-naphthoquinone was added with stirring at 30 ° C., and then 5 g of 1,8-diaminonaphthalene was added to methanol. A solution prepared by dissolving 30 g and 3.3 g of tetrahydrofuran was added dropwise over 30 minutes and then reacted for 210 minutes. Then ferric chloride _{(FeCl 3 · 6H 2 O)} 16g
Was added dropwise to 25 g of water over 30 minutes, and the mixture was further reacted for 60 minutes. Then sodium bisulfite 31
A solution prepared by dissolving g in 300 g of water was added over 10 minutes and reacted for 120 minutes. The obtained precipitate was filtered, sufficiently washed with distilled water to remove iron, repeatedly washed with methanol and styrene, and then dried under reduced pressure to obtain a quinone-amine compound. When this was analyzed by gel permeation chromatography, the average molecular weight was about 17
It was 000.

Production Example 2 (Synthesis of Scale Inhibitor) 60 g of methanol and 6.7 g of tetrahydrofuran were charged into a reaction vessel, 3.2 g of o-benzoquinone was added with stirring at 30 ° C., and then 1,8 5 g of diaminonaphthalene, 30 g of methanol and 3.
After dropping the solution dissolved in 3 g over 30 minutes, 21
The reaction was allowed for 0 minutes. Then, a solution prepared by dissolving 6 g of cupric chloride (CuCl ₂ ) in 25 g of water was added dropwise over 30 minutes, and further 6
The reaction was allowed for 0 minutes. Then sodium bisulfite 12g
Was added to 300 g of water and added over 10 minutes to add 2
The reaction was allowed for 0 minutes. The obtained precipitate was filtered, sufficiently washed with distilled water to remove the copper content, repeatedly washed with methanol and styrene, and then dried under reduced pressure to obtain a quinone-amine compound. When this was analyzed by gel permeation chromatography, the average molecular weight was about 1900.
It was 0.

Example 1 A stainless steel 5 liter polymerization vessel equipped with a stirrer having an inlet at the bottom was filled with a chemical cleaning liquid consisting of 1 liter of toluene, 1 liter of water, 20 g of palmitic acid and 80 g of sodium metasilicate, and 60 ° C. After being washed for 6 hours, it was washed with pure water. Then, a 1 wt% dimethylformamide solution of the quinone-amine compound obtained in Production Example 1 was prepared, and the amount of 0.5 g / m ² was applied to the inner wall of the polymerization vessel heated to 70 ° C. and the stirrer, and dried. . The tricalcium phosphate fine powder 3 was placed in the polymerization vessel thus treated.
3 liters of water containing 000 ppm, polyvinyl alcohol 50 ppm, and .alpha.-olefin sodium sulfonate 50 ppm was added, and the mixture was stirred at 30 rpm. Next, a styrene monomer in which 0.4% of benzoyl peroxide as an initiator was dissolved was added to 500 by using a droplet generator installed in the lower part of the polymerization vessel.
It is jetted into water from a nozzle with a diameter of 0.2 mm while applying a vibration of Hz to form a droplet group of styrene monomer having a diameter of 0.6 mm, and the buoyancy of the droplets is utilized to introduce it from the inlet at the bottom of the polymerization vessel. 500 g was introduced into the polymerization vessel. The styrene monomer suspension thus obtained was heated to 90 ° C. and polymerized for 6 hours. After the polymer was taken out, the polymerization vessel and the stirrer were observed, and scale adhesion was hardly seen.
Without re-application of the scale inhibitor, only the above-mentioned polymerization operation was repeated four more times to measure the scale adhesion amount. The results are shown in Table 1. In addition, the increased weight of the device was used as the scale amount.

Example 2 Evaluation was made in the same manner as in Example 1 except that the polymerization vessel was not heated when the scale inhibitor was applied. The results are shown in Table 1.

Example 3 Evaluations were made in the same manner as in Example 1 except that the scale inhibitor obtained in Production Example 2 was used. The results are shown in Table 1.

Comparative Example 1 Evaluation was made in the same manner as in Example 1 except that the treatment with the scale inhibitor was not carried out. The results are shown in Table 1.

[0019]

[Table 1]

Example 4 Example 1 was placed in a stainless steel 5 liter polymerization vessel equipped with a stirrer.
Fill a chemical cleaning solution with the same composition used in
After washing at 0 ° C. for 6 hours, it was washed with pure water. Then, a 1 wt% dimethylformamide solution of the quinone-amine compound obtained in Production Example 1 was prepared, and the amount of 0.5 g / m ² was applied to the inner wall of the polymerization vessel heated to 70 ° C. and the stirrer and dried. . To the polymerization vessel thus treated, 1.8 liters of water containing 1500 ppm of fine powder of tribasic calcium phosphate and 50 ppm of sodium .alpha.-olefin sulfonate was added and stirred at 230 rpm. Next, styrene monomer 180 in which 0.4% of benzoyl peroxide as an initiator was dissolved
0 g was introduced. Then, it was heated to 90 ° C. and polymerized for 6 hours. After the polymer was taken out, the polymerization vessel and the stirrer were observed, and scale adhesion was hardly seen. Without reapplying the scale inhibitor, only the above-mentioned polymerization operation was repeated twice more to measure the scale adhesion amount. The results are shown in Table 2. In addition, the increased weight of the device was used as the scale amount.

Comparative Example 2 Evaluation was made in the same manner as in Example 4 except that the treatment with the scale inhibitor was not carried out. The results are shown in Table 4.

[0022]

[Table 2]

[0023]

EFFECTS OF THE INVENTION According to the method for producing a styrene resin of the present invention, since the scale attached to the inside of the polymerization vessel can be extremely reduced, the quality and yield of the product can be improved and the frequency of scale removal cleaning can be improved. The effect is to reduce the amount and improve the operating rate of the polymerization vessel.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Toshihiko Hasegawa 6-3-23 Kitahonso, Harima-cho, Kako-gun, Hyogo Prefecture

Claims (8)

[Claims] 1. A styrene-based monomer which is characterized in that an addition reaction product of a quinone compound and an amine compound is applied in advance to the inner wall of the polymerization vessel, a stirrer, and other portions where the monomer comes into contact to carry out suspension polymerization. Suspension polymerization of the body. 2. An addition reaction product of a quinone compound and an amine compound is obtained by subjecting an aromatic quinone and an aromatic diamine to an addition reaction in a solvent, and then polymerizing them by anodic oxidation with an oxidizing agent or an electrode. Molecular weight of 3000
The polymerization method according to claim 1, which is a reduction product of the above quinone-amine compound and / or this quinone-amine compound. 3. The aromatic ring of aromatic quinone is a benzene ring,
The polymerization method according to claim 2, which is a naphthalene ring or a phenanthrene ring. 4. The aromatic ring of the aromatic diamine is a benzene ring, a naphthalene ring or a phenanthrene ring.
Or the polymerization method described in 3. 5. The polymerization method according to claim 1, wherein the addition reaction product of the quinone compound and the amine compound is dissolved or dispersed in an organic solvent, coated and then dried. 6. The polymerization method according to claim 5, wherein the organic solvent is dimethylformamide. 7. The polymerization method according to claim 1, wherein the coated surface is heated to 50 to 90 ° C. when the addition reaction product of the quinone compound and the amine compound is coated. 8. After the liquid column of the styrene-based monomer ejected from the nozzle into the aqueous dispersion medium is subjected to regular vibrational disturbance, a group of monomer droplets having a uniform diameter is formed in the aqueous dispersion medium. The polymerization method according to any one of claims 1 to 7, wherein the suspension polymerization is carried out under a gentle stirring condition in which the droplets do not fragment.