JPH02292303A - Prevention of deposition of polymer scale - Google Patents

Abstract

PURPOSE:To prevent the deposition of polymer scale on the inside wall, etc., of a polymerizer by polymerizing an ethylenically unsaturated monomer in a polymerizer having an inside wall treated with a treating fluid containing an aromatic amine compound, an oxidizing agent and a Brphinsted acid. CONSTITUTION:An ethylenically unsaturated monomer is polymerized in a polymerizer having an inside wall treated with a treating fluid containing an aromatic amine compound (A), an oxidizing agent (B) and a Brphinsted acid (C). As the aromatic amine compound (A), aniline, 1,4-diaminobenzene, 1,8- naphthalenediamine or 4-aminodiphenylamine is desirable. As the oxidizing agent (B), potassium persulfate, ammonium persulfate or ferric chloride is desirable. As the Brphinsted acid (C), HBF4 or H2SO4 is desirable.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is capable of effectively preventing the adhesion of polymer scale to the inner wall surface of a polymerization vessel during the polymerization of monomers having ethylenic double bonds. Regarding how it can be done.

[Conventional technology]

BACKGROUND ART In a method of producing a polymer by polymerizing monomers in a polymerization vessel, there is a known problem that the polymer adheres as scale to the inner wall surface of the polymerization vessel. If polymer scale adheres to the inner wall surface of the polymerization vessel, the polymer yield and cooling capacity of the polymerization vessel may decrease, and the adhered polymer scale may peel off and be mixed into the product, resulting in a decrease in the quality of the product polymer. Furthermore, there are disadvantages such as a great deal of effort and time being required to remove the polymer scale.

Conventionally, as a method for preventing polymer scale from adhering to the inner wall surface of a polymerization vessel, for example, a method of applying polar compounds, dyes, pigments, etc. to the inner wall surface (Japanese Patent Publication Nos. 45-30343 and 45-30835) has been used. , a method of applying an aromatic amine compound (Japanese Unexamined Patent Publication No. 51-50887), a method of applying a reaction product of a phenolic compound and an aromatic aldehyde (Japanese Unexamined Patent Publication No. 55-54317), etc. have been proposed. .

These methods are effective in preventing polymer adhesion in the polymerization of vinyl halide monomers such as vinyl chloride, or monomer mixtures mainly consisting of vinyl chloride and containing a small amount of monomers that can be copolymerized with this monomer. It is.

[Problem to be solved by the invention]

However, if the monomer to be subjected to polymerization is a monomer having other ethylenic double bonds such as styrene, α-methylstyrene, acrylate ester, or acrylonitrile, these monomers has a significantly large dissolving power for the coating film formed by the above-mentioned adhesion prevention method, so part or all of the coating film is dissolved and lost, resulting in the polymer adhering to the inner wall surface of the polymerization vessel, etc. cannot be effectively prevented.

Therefore, an object of the present invention is to provide a method that can effectively prevent the deposition of polymer scale in the polymerization of not only halogenated vinyl monomers but also monomers having a wide range of ethylenic double bonds. It's about doing.

[Means for Solving the Problems] To solve the above problems, the present invention provides a method for preventing the deposition of polymer scale during the polymerization of a monomer having an ethylenic double bond in a polymerization vessel. , the inner wall surface of the polymerization vessel, and preferably other parts with which the monomer comes into contact during polymerization: (Δ) aromatic amine compound, (
The present invention provides a method for preventing the adhesion of polymer scale, which comprises carrying out the polymerization in a polymerization vessel treated with a treatment solution containing B) an oxidizing agent and (C) a Brønsted acid.

Examples of aromatic amine compounds that are component (A) of the treatment liquid used in the present invention include aniline, 2-methylaniline, 3-methylaniline, 2-ethylaniline,
-ethylaniline, 1,2 diaminobenzene, 1.3-
Diaminobenzene, 1.4-diaminobenzene, 3-bromo1. 2-diaminobenzene, 3-nitro-1
．． 2-diaminobenzene, 3-methyl-1,2-diaminobenzene, 3-methoxy-1,2-diaminohenzene, 3-trifluoromethyl-1,2-diaminobenzene, 3,5-dimethyl-1,2 -diaminobenzene, 3,
5-dimethoxy-1,2-diaminobenzene, 1,8-
Naphthalenediamine, 1,5-naphthalenediamine, 2
, 3-naphthalenediamine, 5-amino-2-(3-amino-4-toluidino)benzenesulfonic acid, 2-amino-4-nitrophenol, 2-aminephenol, 4-amino-2-nitrophenol, 4-aminodiphenylamine, 4 , 4'-diaminodiphenylamine, 4-hydroxydiphenylamine, and the like. These may be used alone or in combination of two or more. Among these, aniline = 1,4-diaminobenzene, 1,8
-Naphthalenediamine and 4-aminodiphenylamine are preferred.

The oxidizing agent that is component (B) of the treatment solution includes water-soluble organic or inorganic peroxides, such as cumene hydroperoxide, hydrogen peroxide, potassium persulfate, ammonium persulfate, and potassium perchlorate. , sodium perchlorate, cesium sulfate, potassium permanganate, potassium dichromate, ferric chloride, and the like. Among these, potassium persulfate, ammonium persulfate, and ferric chloride are preferred.

In addition, the (C) component of the treatment liquid, Brönsted? For example, IIBF. , HC f O4, IICf
, CH3COOH . ．． CF3COOH, llZs
Examples include O4, lINO*, and the like. These may be used alone or in combination of two or more. Also among these, }IBF. and 11■SO. is preferred.

The treatment liquid can be prepared by dissolving or dispersing the above-mentioned aromatic amine compound, oxidizing agent, and Bronsted acid in an appropriate solvent.

The solvent used is not particularly limited as long as it is water or an organic solvent miscible with water and is not oxidized by the oxidizing agent (B) used. For example, dioxane,
Examples include ethers such as methyldioxolane and tetrahydrofuran; glycols such as ethylene glycol diethyl ether, ethylene glycol, and cellosolve; and nitrites such as acetonitrile. These solvents may be used alone or as a mixed solvent in combination of two or more.

The concentration of the aromatic amine compound (A) in the treatment liquid is usually
Preferably 0. Ol to 2% by weight, more preferably 0.
05 to 1% by weight. The concentration of the oxidizing agent (B) is usually preferably 0.001 to 8 mol, more preferably 0.0 mol, per 1 mol of the aromatic amine compound in the treatment liquid.
The amount is 1 to 4 moles.

(C) The concentration of the Pronsted acid is usually preferably 0.00 per mole of the aromatic amine compound in the treatment liquid.
1 to 8 mol, more preferably 0. The amount is such that the proportion is 4 moles.

In the method of the present invention, the treatment liquid prepared as described above is preferably applied to the inner wall surface of the polymerization vessel and preferably to other parts with which monomers come into contact during polymerization, such as a stirring shaft or a stirring blade. The inner wall surface of the polymerization vessel, etc. is treated by contacting them at a temperature of 0 to 100°C, particularly preferably 5 to 60°C. This treatment may be carried out continuously, preferably for 30 minutes or more, more preferably for 60 minutes or more. The treated solution after treatment may be discharged from the polymerization vessel.

After treating and washing with water the inner wall of the polymerization vessel and preferably other parts that come into contact with the monomer during polymerization, the monomer having an ethylenic double bond is added to the polymerization vessel in accordance with a conventional method. Polymerization initiator, other required polymerization medium,
Additives, for example, monomeric resolution aids may be added and polymerized.

Examples of monomers having an ethylenic double bond to which the method of the present invention is applied include vinyl halides such as vinyl chloride, vinyl esters such as vinyl acetate and vinyl propionate, acrylic acid, methacrylic acid, and their like. Examples include esters or salts, maleic acid or fumaric acid, and their esters or anhydrides, diene monomers such as butadiene, chloroprene, and isoprene, as well as styrene, acrylonitriles, vinylidene halides, and vinyl ethers.

The method of the present invention is effective regardless of the material of the inner wall of the polymerization vessel, and is also effective in, for example, polymerization using a stainless steel polymerization vessel, a glass-lined polymerization vessel, or the like.

Further, the method of polymerization to which the method of the present invention is applied is not particularly limited, and any polymerization method such as suspension polymerization, emulsion polymerization, solution polymerization, and bulk polymerization is effective.

Therefore, any commonly used additives added to the polymerization system can be used without any restrictions. That is,
For example, partially saponified polyvinyl vinyl. Suspending agents such as alcohol, methyl cellulose, and polyacrylate; Calcium phosphate; Solid nt agents such as hydroxy abatite; Anionic emulsifiers such as sodium lauryl sulfate, sodium dodecylbenzenesulfonate, and sodium dioctyl sulfosuccinate; Sorbitan Nonionic emulsifiers such as monolaurate and polyoxyethylene alkyl ether; Fillers such as calcium carbonate and titanium oxide; tribasic lead sulfate;
Calcium stearate, diptyltin dilaurate,
Stabilizers such as dioctyltin mercaptide; lubricants such as rice wax and stearic acid; plasticizers such as DOPSDBP; chain transfer agents such as trichlorethylene and mercaptan;
p11 regulator; polymerization catalysts such as diisopropyl peroxydicarbonate, α, α′-azobis-2,4-dimethylbaret nitrile, lauroyl peroxide, potassium persulfate, cumene hydroperoxide, p-menthane hydroperoxide, etc. Even in existing polymerization systems, the method of the present invention can effectively prevent the deposition of polymer scale.

Polymerizations in which the method of the present invention is particularly preferably carried out include, for example,
Vinyl halides such as vinyl chloride or vinylidene halides, . Or suspension polymerization or emulsion polymerization of a monomer mixture mainly consisting of these. We also manufacture beads and latex of polymers such as polystyrene, polymethyl methacrylate, and polyacrylonitrile in stainless steel polymerization vessels, SBR, NBR. ．． CR, IR, I I
Manufacture of synthetic rubbers such as R (these synthetic rubbers are usually
Manufactured by emulsion polymerization. ), are also suitable for polymerization to produce ABS resins.

〔Example〕

Next, the method of the present invention will be explained using Examples and Comparative Examples. In each table below, the experiments Nα marked with * are comparative examples, and the other experiments Nα are examples of the present invention.

Example 1-10, Comparative Examples 1-2 In each example, 15 liters of pure water was first charged into a stainless steel polymerization vessel with an internal volume of 2Off and equipped with a stirrer, an aromatic amine compound and Brønsted acid were added, and an oxidizing agent was added. Prepare a processing solution by preparing a solution dissolved in 3 liters of pure water,
After treating the inner wall surface of the polymerization vessel and other areas in contact with the monomer during polymerization under the treatment conditions shown in Table 1, the treatment liquid was discharged from the inside of the polymerization vessel and the inside of the polymerization vessel was washed with water. However, in Comparative Example 1, no treatment was performed with a treatment liquid, and in Comparative Example 2, treatment was performed with a treatment liquid containing only an aromatic amine compound. The aromatic amine compound, oxidizing agent, and blendsted acid used in each example, as well as the concentration of each component, are shown in Table 1. Thereafter, 7000 g of water, 70 g of hydroxyapatite, and dodecylbenzenesulfone were added to the polymerization vessel treated in this way. acid sodium O. 14 g of benzyl peroxide, 17.5 g of benzyl peroxide, and 10.5 g of t-butyl perbenzoate were charged and reacted at 92°C for 3.5 hours. Next, a polymer was prepared by reacting at 135°C for 1 hour.

After the polymerization was completed, the amount of polymer scale attached to the inner wall surface of the polymerization vessel was measured. The results are shown in Table 1.

Examples 11 to 14, Comparative Examples 3 to 4 In each example, the inner wall surface of a stainless steel polymerization vessel with an internal volume of 202 and equipped with a stirrer and other parts that come into contact with the monomer during polymerization were made in the same manner as in Example 1. It was treated with a treatment solution prepared by However, in Comparative Example 3, no treatment was performed with a treatment liquid, and in Comparative Example 4, treatment was performed with a treatment liquid containing only an aromatic amine compound. Table 1 shows the aromatic amine compound, oxidizing agent, and protonic acid used in each example, as well as the concentrations of each component.

Next, in the polymerization vessel treated in this way, 400 kg of water,
Styrene 260 kg, acrylonitrile 140 kg
, 400 g of partially saponified polyacrylamide and α. α
Prepare 1.2 kg of '-azobisisobutyronitrile,
A polymer was prepared by reacting at 90'C for 5 hours.

After the polymerization was completed, the amount of polymer scale attached to the inner wall surface of the polymerization vessel was measured. The results are shown in Table 1.

〔Effect of the invention〕

According to the method of the present invention, it is possible to effectively prevent polymer scale from adhering to the inner wall surface of a polymerization vessel during the polymerization of a monomer having an ethylenic double bond, which has been difficult in the past. In particular, it is possible to prevent the adhesion of polymer scale even in the polymerization of polymer systems containing monomers with high solubility, such as styrene, α-methylstyrene, acrylic esters, acrylonitrile, and the like. By treating the inner wall surface of the polymerization vessel with the treatment liquid in every batch or once every few batches, the polymerization vessel can be used repeatedly without adhesion of polymer scale.

Agent Patent Attorney Shushi Iwamiya

Claims (1)

[Claims] A method for preventing the adhesion of polymer scale during the polymerization of a monomer having an ethylenic double bond in a polymerization reactor, the inner wall surface of the polymerization reactor being preliminarily treated with (A) an aromatic amine compound, (B) an oxidized A method for preventing the adhesion of polymer scale, which comprises carrying out the polymerization in a polymerization vessel treated with a treatment solution containing a Brønsted acid and (C) a Brønsted acid.