JPH0699489B2 - Polymer scale adhesion prevention method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention can effectively prevent the adhesion of polymer scale to the inner wall surface of a polymerization vessel in the polymerization of a monomer having an ethylenic double bond. Regarding how you can.

[Conventional technology]

In a method of 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. If polymer scale adheres to the inner wall surface of the polymerization vessel, the yield of the polymer and the cooling capacity of the polymerization vessel will decrease, and the adhered polymer scale will peel off and enter the product, resulting in deterioration of the quality of the product polymer. Further, there are disadvantages such that a great amount of labor and time are required for removing the polymer scale.

Conventionally, as a method of preventing the adhesion of polymer scale to the inner wall surface of the polymerization vessel, for example, a method of applying a polar compound, dye, pigment, etc. to the inner wall surface (Japanese Patent Publication Nos. 45-30343 and 45-3).
No. 0835), a method of applying an aromatic amine compound (Japanese Patent Application Laid-Open No. Sho.
51-50887), a method of applying a reaction product of a phenolic compound and an aromatic aldehyde (JP-A-55-54317), and the like.

These methods are effective for preventing polymer adhesion in the polymerization of vinyl halide monomers such as vinyl chloride or a monomer mixture containing the monomer as a main component and a small amount of a monomer copolymerizable therewith. Is.

[Problems to be Solved by the Invention]

However, when the monomer used for the polymerization is a monomer having another ethylenic double bond such as styrene, α-methylstyrene, acrylic acid ester and acrylonitrile, these monomers are Since it has a remarkably large dissolving ability for the coating film formed by the adhesion prevention method, some or all of the coating film is dissolved and lost, and as a result, the adhesion of the polymer to the inner wall surface of the polymerization vessel is effective. Cannot be prevented.

Therefore, an object of the present invention is to provide a method capable of effectively preventing the adhesion of polymer scale in the polymerization of monomers having a wide range of ethylenic double bonds, not limited to vinyl halide monomers. To do.

[Means for Solving the Problems]

The present invention is a method for preventing the adhesion of polymer scale in the polymerization of a monomer having an ethylenic double bond in a polymerization vessel, as a solution to the above-mentioned problems, and a polymerization vessel inner wall surface, and preferably The other part which the monomer contacts during polymerization is previously selected from at least one selected from the group consisting of (A) aromatic amine compound, (B) oxidizing agent and (C) HBF ₄ and H ₂ SO _4. The present invention provides a method for preventing adhesion of polymer scale, which comprises performing the above-mentioned polymerization in a polymerization vessel which is treated with a treatment liquid containing seeds at 5 to 60 ° C.

Examples of the aromatic amine compound which is the component (A) of the treatment liquid used in the present invention include aniline, 2-methylaniline, 3-methylaniline, 2-ethylaniline and 3
-Ethylaniline, 1,2-diaminobenzene, 1,3-diaminobenzene, 1,4-diaminobenzene, 3-bromo-
1,2-diaminobenzene, 3-nitro-1,2-diaminobenzene, 3-methyl-1,2-diaminobenzene, 3-methoxy-1,2-diaminobenzene, 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-aminophenol, 4-amino-2-nitrophenol, 4-aminodiphenylamine, 4,4'-diaminodiphenylamine, 4-hydroxydiphenylamine and the like can be mentioned.
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 preferable.

Examples of the oxidizing agent that is the component (B) of the treatment liquid include water-soluble organic or inorganic peroxides, such as cumene hydroperoxide, hydrogen peroxide, potassium persulfate, ammonium persulfate, potassium perchlorate. , Sodium perchlorate, cesium sulfate, potassium permanganate, potassium dichromate, ferric chloride and the like. Among these, potassium persulfate, ammonium persulfate and second chloride
Iron is preferred.

Further, as the component (C) of the treatment liquid, HBF ₄ and / or H ₂
SO ₄ is used.

The treatment liquid can be prepared by dissolving or dispersing the above components (A) to (C) in a suitable 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, and examples thereof include dioxane,
Ethers such as methyldioxolane and tetrahydrofuran; glycols such as ethylene glycol diethyl ether, ethylene glycol and cellosolve; nitriles such as acetonitrile. These are appropriately used alone or in combination of two or more as a mixed solvent.

The concentration of the aromatic amine compound (A) in the treatment liquid is usually
Preferably 0.01 to 2% by weight, more preferably 0.05 to 1
% By weight. The concentration of the (B) oxidizing agent is usually preferably 1 mol of the aromatic amine compound in the treatment liquid.
The amount is 0.001 to 8 mol, more preferably 0.01 to 4 mol. The concentration of the component (C) is usually preferably 0.00 based on 1 mol of the aromatic amine compound in the treatment liquid.
The amount is 1 to 8 mol, more preferably 0.01 to 4 mol.

In the method of the present invention, the treatment liquid prepared as described above is used on the inner wall surface of the polymerization vessel and, preferably, on the other portion where the monomer comes into contact during the polymerization, such as a stirring shaft or a stirring blade.
At the temperature of 60 ° C, the inner wall surface of the polymerization vessel is treated by bringing them into contact with each other. This treatment is usually preferably continuously performed for 30 minutes or longer, more preferably 60 minutes or longer. The treated liquid after the treatment may be discharged from the polymerization vessel.

In this way, the inner wall of the polymerization vessel and, preferably, after treating the portion where other monomers come into contact during the polymerization and washing with water, a monomer having an ethylenic double bond according to a conventional method in this polymerization vessel, Polymerization initiator, other required polymerization medium,
An additive, for example, a dispersion aid of a monomer may be charged and polymerized.

As the monomer having an ethylenic double bond to which the method of the present invention is applied, for example, vinyl halide such as vinyl chloride, vinyl acetate, vinyl ester such as vinyl propionate, acrylic acid, methacrylic acid or their Examples thereof include esters or salts, maleic acid or fumaric acid, and esters or anhydrides thereof, diene monomers such as butadiene, chloroprene and isoprene, and styrene, acrylonitrile, vinylidene halide, vinyl ether and the like.

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

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

Therefore, as the additive substance to be added to the polymerization system, those usually used can be used without any restrictions. That is,
For example, suspending agents such as partially saponified polyvinyl alcohol, methyl cellulose, and polyacrylate; solid dispersants such as calcium phosphate: hydroxyapatite; anionic emulsifiers such as sodium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium dioctylsulfosuccinate; sorbitan monolaur. Rate, nonionic emulsifiers such as polyoxyethylene alkyl ether; fillers such as calcium carbonate and titanium oxide; stabilizers such as tribasic lead sulfate, calcium stearate, dibutyltin dilaurate, dioctyltin mercaptide; rice wax, stearic acid, etc. Lubricants; plasticizers such as DOP and DBP; chain transfer agents such as trichlorethylene and mercaptan; pH adjusters; diisopropyl peroxydicarbonate, α,
α'-azobis-2,4-dimethylvaleronitrile, α,
Even in a polymerization system in which a polymerization catalyst such as α'-azobisisobutyronitrile, lauroyl peroxide, potassium persulfate, cumene hydroperoxide, p-menthane hydroperoxide, etc. is present, the method of the present invention is a polymer scale. Can be effectively prevented.

Polymerizations in which the process of the invention is particularly preferably carried out include, for example:
It is suspension polymerization or emulsion polymerization of vinyl halide such as vinyl chloride or vinylidene halide, or a monomer mixture mainly containing them. Further, polystyrene in a polymerization vessel made of stainless steel, polymethylmethacrylate, beads of polymers such as polyacrylonitrile, production of latex, production of synthetic rubber such as SBR, NBR, CR, IR, IIR (these synthetic rubbers are usually It is also suitable for polymerization for producing ABS resin.

〔Example〕

Next, the method of the present invention will be described with reference to Examples and Comparative Examples.

In each of Examples 1 to 3 and Comparative Examples 1 to 2, first, pure water 15 was charged into a stainless steel polymerization vessel equipped with a stirrer and having an internal volume of 20 to prepare an aromatic amine compound,
And HBF ₄ or H ₂ SO ₄ were further added, and a treatment solution was prepared by adding a solution prepared by dissolving an oxidizer in pure water 3. Under the treatment conditions shown in Table 1, the inner wall surface of the polymerization vessel and other polymerization were performed. After treating the portion where the monomer comes into contact with the treatment liquid, 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, the treatment with the treatment liquid was not performed, and in Comparative Example 2,
It was treated with a treatment liquid containing only an aromatic amine compound. Aromatic amine compound, oxidant, and HBF ₄ used in each example
Table 1 shows the concentrations of H ₂ SO ₄ and each component.

Next, 400 kg of water, 260 kg of styrene, 140 kg of acrylonitrile, 400 g of partially saponified polyacrylamide and 1.2 kg of α, α′-azobisisobutyronitrile were charged into the polymerization vessel thus treated, and the mixture was heated at 90 ° C. for 5 hours. A polymer was produced by reacting. 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.

Comparative Example 3 20 g of aniline and 6 g of potassium persulfate were mixed with 2000 ml of water and reacted at 20 ° C. for 8 hours. Then, 20 g of concentrated sulfuric acid was added to the resulting reaction solution, and the mixture was further reacted at 20 ° C. for 8 hours. Then, the precipitate and the precipitate in the container were filtered and dried to obtain 13 g of a condensate.

The obtained condensate was insoluble in water, methanol, ethanol, and acetone, and was only slightly soluble in DMF (N, N-dimethylformamide).

Next, 10 g of the condensate obtained above was mixed with 1000 ml of DMF to obtain a coating liquid.

This coating solution was applied to the inner wall surface of a stainless steel polymerization vessel equipped with a stirrer with an internal volume of 20 and other portions where the monomer comes into contact during the polymerization, and dried by heating at 90 ° C. for 30 minutes.

Then, a polymer was produced in the same manner as in Example 1.

After the completion of the polymerization, the amount of the polymer scale attached to the inner wall surface of the polymerization vessel was measured and found to be 290 g / m ² . The results are shown in Table 1.

Comparative Example 4 20 g of 4-aminodiphenylamine and 28 g of ammonium persulfate were mixed with 4000 ml of water and reacted at 20 ° C. for 9 hours.
Thereafter, 100 g of a 10% tetrafluoroboric acid aqueous solution was added to the obtained reaction solution, and the mixture was further reacted at 20 ° C. for 9 hours to obtain 16 g of a condensate.

This condensate, like the condensate of Comparative Example 3, is insoluble in water, methanol, ethanol, and acetone, and DMF (N, N-
It was only slightly soluble in dimethylformamide).

A polymer was produced in the same manner as in Comparative Example 3 using the condensate obtained in this example.

After the completion of the polymerization, the amount of the polymer scale attached to the inner wall surface of the polymerization vessel was measured and found to be 260 g / m ² . The results are shown in Table 1.

[Effect of the Invention] According to the method of the present invention, it has been difficult in the past. It is possible to effectively prevent adhesion of the polymer scale to the inner wall surface of the polymerization vessel in the polymerization of the monomer having an ethylenic double bond. In particular, it is possible to prevent the adhesion of the polymer scale even in the polymerization of a polymerization system containing a monomer having a high solubility, for example, styrene, α-methylstyrene, acrylic ester, acrylonitrile and the like. By performing the treatment of the inner wall surface of the polymerization vessel with the treatment liquid once in every batch or every several batches, the polymerization vessel can be repeatedly used without attaching the polymer scale.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mikio Watanabe 1 Towada, Kamisu-cho, Kashima-gun, Ibaraki Prefecture Shin-Etsu Chemical Co., Ltd. Polymer Functional Materials Research Center (56) References Japanese Patent Publication No. 62-20201 ( JP, B2)

Claims (1)

[Claims] 1. A method for preventing the adhesion of a polymer scale in the polymerization of a monomer having an ethylenic double bond in a polymerization vessel, wherein the inner wall surface of the polymerization vessel is (A) an aromatic amine compound in advance. , (B) oxidant and (C) HBF ₄ and H ₂ SO
_A method for preventing adhesion of a polymer scale, which comprises performing the above-mentioned polymerization in a polymerization vessel which is treated at 5 to 60 ° C. with a treatment liquid containing at least one selected from the group consisting of ₄ .