JPH0617367B2 - Polymer scale adhesion prevention method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for preventing polymer scale from adhering to the inner wall surface of a polymerization vessel or the like in the polymerization of a monomer having an ethylenic double bond.

[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, etc., 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 for preventing adhesion of 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. 30343/45,
-30835), a method of applying an aromatic amine compound (JP-A-51-50887), and a method of applying a reaction product of a phenolic compound and an aromatic aldehyde (JP-A-55-5431).
No. 7) etc. have been proposed.

These methods are effective in preventing the adhesion of polymer scale in the polymerization of a vinyl halide monomer 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 ester, acrylonitrile, these monomers are Since it has a remarkably large dissolving ability for the coating film formed by the adhesion prevention method, part or all of the coating film is dissolved and lost, and as a result, the adhesion of the polymer scale to the inner wall surface of the polymerization vessel is prevented. It cannot be effectively prevented.

Therefore, the present invention is not limited to vinyl halide monomers, in the polymerization of monomers having a wide range of ethylenic double bond, to effectively prevent the adhesion of the polymer scale to the inner wall surface of the polymerization vessel. It is to provide a method that can.

[Means for Solving the Problems]

The present inventors have found that the above object can be achieved by applying a coating solution containing three kinds of specific compounds to the inner wall surface of the polymerization vessel.

That is, the present invention provides a method for preventing the adhesion of polymer scale in the polymerization of a monomer having an ethylenic double bond in a polymerization vessel, which is to solve the above-mentioned problems. At least 1 selected from (a) an aromatic amine compound condensate and (b) an alkali metal salt and ammonium salt of a sulfonated product of the aromatic amine compound condensate in advance in the other portion with which the monomer contacts. And a method for preventing the adhesion of a polymer scale, which comprises performing the above-mentioned polymerization in a polymerization vessel coated with a coating liquid containing at least one selected from the group consisting of (c) a metal compound and an inorganic colloid. is there.

Examples of the aromatic amine compound condensate which is the component (a) of the coating solution used in the present invention include, for example, JP-B-60-30681.
A condensate obtained by reacting an aromatic amine compound and an aromatic nitro compound in the temperature range of 100 to 250 ° C. in the presence of a condensation catalyst, or an alkali metal salt or an ammonium compound of the condensate. Bases; linear or branched polyaromatic amines having a molecular weight of about 250 or more as described in JP-B-59-16561 and JP-B-60-54323; JP-A-61-7309 Aromatic diamine and aromatic quinone described are subjected to an addition reaction in a solvent having a solubility parameter of 9.0 to 12.2 alone or in a mixed solvent or in a mixed solvent containing an alcohol in an amount equal to or less than that of the solvent, and obtained by precipitation separation. Average molecular weight 3000
The above quinone-amine compounds and the like can be mentioned.
These may be used alone or in combination of two or more.

Examples of the alkali metal salt or ammonium salt of the sulfonated product of the aromatic amine compound condensate used as the component (b) of the coating liquid include the component (a) as described in JP-B-61-52161. Examples thereof include those obtained by sulfonation of a condensate of an aromatic amine compound and then reacting with an alkali metal compound or an ammonium compound. Sulfonation of an aromatic amine compound condensate can be carried out according to a conventionally known method, for example, using sulfuric acid, fuming sulfuric acid, chlorosulfonic acid or the like as a sulfonating agent, and reacting at a reaction temperature of 35 to 90 ° C. The sulfonated product can be obtained by reacting the agent at a concentration of 2 to 15 times (concentration) of the condensate. Then, the obtained sulfonated compound is reacted with an alkali metal compound or an ammonium compound to obtain the component (b).
This reaction involves, for example, dispersing the sulfonated product in water,
It can be carried out by adding an alkali metal compound or an ammonium compound under heating and reacting. Examples of the alkali metal compound used include NaOH and KO
H, Na ₂ CO _{3 and the} like can be mentioned. Examples of ammonium compounds include NH ₄ OH, (NH ₄ ) ₂ CO _{3, and the} like. The product obtained by this reaction is water-soluble and is obtained in the form of being dissolved in an aqueous medium. Therefore, the product may be evaporated to dryness, and the obtained dried solid product may be pulverized into a powder form.

The component (b) obtained by these reactions may be used alone or in combination of two or more.

Examples of the metal compound that is the component (C) of the coating liquid include metal salts, metal oxides, metal hydroxides, and the like. For example, alkali metals such as sodium and potassium; alkaline earth metals such as magnesium, calcium, and barium. Zinc group metals such as zinc; aluminum group metals such as aluminum; tin group metals such as titanium and tin; iron group metals such as iron and nickel; chromium group metals such as chromium and molybdenum;
Manganese group metals; Copper group metals such as copper and silver; Metal silicates such as platinum group metals such as platinum; carbonates, phosphates, sulfates, nitrates, borates, acetates, hydroxides; Oxide,
Examples thereof include halides. Further, examples of the inorganic colloid used in the coating liquid include gold colloid, silver colloid, sulfur colloid, ferric hydroxide colloid, stannic acid colloid, silicic acid colloid, manganese dioxide colloid, molybdenum oxide colloid, and sulfuric acid. Examples thereof include barium colloid, vanadium pentoxide colloid, aluminum hydroxide colloid, lithium silicate colloid and the like prepared by mechanical grinding, ultrasonic irradiation, electrical dispersion, chemical treatment and the like.

These metal compounds and inorganic colloids may be used alone or in combination of two or more.

The coating liquid used in the method of the present invention is the above-mentioned component (a),
It is prepared by dissolving or dispersing the component (b) and the component (c) in a suitable solvent. The total concentration of the components (a), (b) and (c) in the coating liquid is usually 0.01 to 5% by weight, preferably 0.05 to 2% by weight. In addition, the content ratio of each component in the coating liquid is usually 1 to 500 parts by weight, preferably 5 to 300 parts by weight, and (c) to 100 parts by weight of the component (a). The components are 5 to 400 parts by weight, preferably 15 to 250 parts by weight.

If the component (b) is too much or too small compared to the component (a), the component (a) will agglomerate and a uniform coating cannot be obtained if it is too small, or the coating solution will be applied to the inner wall surface of the polymerization vessel and dried. After that, the coating film may be dissolved by washing with water. If the amount of the component (c) is too large or too small as compared with the component (a), the effect of preventing adhesion of the polymer scale obtained by using the component (b) and the component (c) together may not be obtained. is there.

As a solvent for dissolving or dispersing the components (a), (b) and (c), methanol, ethanol, propanol, butanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2- Propanol,
Alcoholic solvents such as 3-methyl-1-butanol, 2-methyl-2-butanol, 2-pentanol; n-
Aliphatic hydrocarbon solvents such as hexane and n-heptane;
Aromatic hydrocarbon solvents such as benzene, toluene, xylene; methylene chloride, 1-chlorobutane, amyl chloride,
Halogenated hydrocarbon solvents such as dichloroethylene and 1,1,2-trichloroethane; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as methyl formate, ethyl formate, methyl acetate and methyl acetoacetate. Examples thereof include ether solvents such as 4-methyldioxolane and ethylene glycol diethyl ether; furans; aprotic solvents, water and the like, and these are appropriately used alone or as a mixed solvent of two or more kinds.

In the method of the present invention, in order to form a coating film for preventing the adhesion of the polymer scale on the inner wall surface of the polymerization vessel, the above (a),
The coating liquid containing the components (b) and (c) is applied to the inner wall surface of the polymerization vessel and other portions with which the monomer contacts during the polymerization, such as a stirring shaft and a stirring blade. This coating operation is carried out by dissolving the components (a), (b) and (c) in a suitable solvent to prepare a coating solution, coating the coating solution on the inner wall of the polymerization vessel, etc., and then at room temperature to 100 ° C It may be dried at the temperature of. Alternatively, the inner wall of the polymerization vessel and other portions where other monomers come into contact with each other are heated in advance (30 to 80 ° C), and the coating solution is applied to the heated surface. In any case, the coated surface is sufficiently dried and then washed with water if necessary. Dry coating amount of thus obtained coating film is usually, 0.001 g / m ² or more, and particularly preferably 0.05 to 2 g / m ^2.

The formation of the coating film in the present invention may be carried out for each batch of polymerization, but the coating film formed once has a considerable durability and the scale preventing action is sustained.
It may be formed in batches several times.

In this way, after the coating treatment is completed on the inner wall of the polymerization vessel and other portions where the monomer contacts during the polymerization, a monomer having an ethylenic double bond is added to the polymerization vessel according to a conventional method,
A polymerization initiator, other required polymerization medium and additives such as 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 their esters or anhydrides, diene-based monomers such as butadiene, chloroprene and isoprene, and styrene, acrylonitrile, vinylidene halide, vinyl ether and 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, partially saponified polyvinyl alcohol, methyl cellulose, polyacrylate, a suspension agent such as polyacrylamide partially saponified product, calcium phosphate, a solid dispersant such as hydroxyapatite, sodium lauryl sulfate,
Anionic emulsifiers such as sodium dodecylbenzene sulfonate and dioctyl sulfosuccinate, sorbitan monolaurate, nonionic emulsifiers such as polyoxyethylene alkyl ether, fillers such as calcium carbonate and titanium oxide, tribasic lead sulfate, calcium stearate Stabilizers such as dibutyltin dilaurate and dioctyltin mercaptide, lubricants such as rice wax and stearic acid, plasticizers such as DOP and DBP, chain transfer agents such as trichlorethylene and mercaptans, pH
Regulator, diisopropyl peroxydicarbonate,
Polymerization such as α, α′-azobis-2,4-dimethylvaleronitrile, α, α′-azobisisobutyronitrile, lauroyl peroxide, potassium persulfate, cumene hydroperoxide, p-menthane hydroperoxide Even in a polymerization system in which a catalyst or the like is present, the method of the present invention can effectively prevent the adhesion of polymer scale.

Polymerizations in which the process according to the invention is particularly preferably carried out are suspension or emulsion polymerizations of vinyl halides such as vinyl chloride or vinylidene halides, or of monomer mixtures based on them. Also, production of beads, latex of polymers such as polystyrene, polymethylmethacrylate and polyacrylonitrile in a stainless steel polymerization vessel, production of synthetic rubbers such as SBR, NBR, CR, IR and IIR (these synthetic rubbers are usually emulsified). It is also suitable for polymerization in which the ABS resin is produced.

〔Example〕

Next, the method of the present invention will be described with reference to Examples and Comparative Examples. In addition, in each of the following tables, the experimental numbers marked with * are comparative examples, and the other experimental numbers are examples of the present invention.

Production Example of Aromatic Amine Compound Condensate (1) Production of Condensate NO.1 aniline 1.00 mol, hydrochloric acid 0.310 mol, nitrobenzene 0.2
A mixture of 27 moles and 0.103 moles of ferric chloride was added to 60
After heating at 60 ° C for 6 hours, the temperature was raised to 180 to 185 ° C to distill off water, and the temperature was maintained for reaction for 15 hours. Aniline and nitrobenzene were distilled out with water during the reaction. Collect the distilled aniline and nitrobenzene,
Returned to the reactor. Next, the internal temperature of the reactor was raised to 200 ° C., and heating was performed at this temperature for 5 hours.

The obtained reaction mixture (melt) was poured into dilute sulfuric acid,
After heating at ℃ for 3 hours, it was filtered while hot to remove unreacted aniline. Next, after washing with water 5 to 6 times to remove hydrochloric acid,
A condensate was obtained by drying.

(2) Preparation of Condensate NO.2 A mixture of 1.00 mol of m-phenylenediamine, 0.10 mol of hydrochloric acid and 0.83 mol of resorcinol was heated at 60 ° C. for 1 hour and then 300 ° C. while removing generated ammonia over 2 hours. The temperature was raised to. When the temperature reached 300 ° C., cooling was started, and the temperature was returned to room temperature for 1 hour to obtain a solid condensate.

(3) Preparation of condensate NO.3 After charging 16.65 mol of THF (tetrahydrofuran) into a reaction vessel, the temperature was raised to 50 ° C and 0.834 mol of 1,4-benzoquinone and 1,8-diaminonaphthalene were stirred.
0.189 mol was added. Next, the stirring was stopped, and the mixture was left at 50 ° C. for 60 days to cause the condensation reaction.

The obtained reaction mixture was filtered, washed with THF 5 to 6 times to remove unreacted 1,4-benzoquinone and 1,8-diaminonaphthalic acid, and dried to obtain a condensate.

After the production condensate NO.150g and concentrated sulfuric acid 300g of the sodium salt of an aromatic amine compound condensates sulfonated product were mixed at 30 ° C. or less, the temperature was raised to 40 ° C., the reaction mixture is rapidly dilute NH ₄ OH Sulfonated by stirring until it became soluble. Next, the reaction mixture was poured into 1000 ml of water, the sulfonation product formed as a precipitate was separated by filtration, washed with water, and then dispersed in 1000 ml of water,
At 90 ° C., 11.3 g of 40 wt% NaOH aqueous solution was added and dissolved. The obtained solution was evaporated and dried to dryness, and then the obtained dried solid was pulverized to obtain 52.0 g of condensate sulfonate NO.1 (sodium salt of sulfonate).

By the same method, the condensates NO.2 and NO.
Sulfonating 3 to give the sulfonated product of each condensate
NO. 255 g and NO. 348 g were obtained.

Example 1 Polymerization was carried out as follows using a stainless steel polymerization vessel with an internal volume of 1000 equipped with a stirrer.

In each experiment, first, as shown in Table 1, the total amount of the components (a), (b) and (c) was 0.5.
Prepare a coating solution by dissolving it in a concentration of wt%, and apply this to the inner wall of the polymerization vessel and other areas where the monomer contacts during polymerization.
It was heated at ℃ for 15 minutes, dried and washed with water. Aromatic amine compound condensate used in each experiment, sodium salt of sulfonate of aromatic amine compound condensate, metal compound or inorganic colloid, and weight ratio of (a) component / (b) component / (c) component, The solvents used are shown in Table 1. However, the experiment
No. 1 to 7 does not apply the coating liquid, or (a) component,
It is a comparative example in which a coating liquid containing only one or two components selected from the component (b) or the component (c) was applied.

After that, 400 k of water was added to the polymerization vessel coated in this way.
g, vinyl chloride 200kg, sorbitan monostearate 200
g, hydroxypropylmethyl cellulose 200 g and diisopropyl peroxydicarbonate 75 g were charged and polymerized at 57 ° C. for 6 hours while stirring. After completion of polymerization
The amount of polymer scale attached to the inner wall of the polymerization vessel was measured. The results are shown in Table 1.

Example 2 The coating liquid was applied to a stainless steel polymerization vessel having an internal volume of 100 and equipped with a stirrer in the same manner as in Example 1. Aromatic amine compound condensate used in each experiment, sodium salt of sulfonated aromatic amine compound condensate, and (a) component /
The weight ratio of component (b) / component (c), the solvent used is second
Shown in the table. However, in Experiment Nos. 21 to 27, the coating liquid was not applied or the coating liquid containing only one or two components selected from the component (a), the component (b) and the component (c). It is the applied comparative example.

Next, 40 kg of water, 17 kg of vinyl chloride, 4 kg of vinyl acetate, 12 g of partially saponified polyvinyl alcohol, 4 g of hydroxypropylmethylcellulose, 200 g of trichloroethylene, and 200 g of trichloroethylene as polymerization catalyst, and α, α′-dimethylvalero as a polymerization catalyst were placed in a polymerization vessel coated as described above. Charge 0.5 kg of nitrile,
The temperature was raised with stirring and polymerization was carried out at 58 ° C. for 6 hours. After the polymerization was completed, the amount of polymer scale attached to the inner wall of the polymerization vessel was measured. The results are shown in Table 2.

Example 3 The coating solution was applied to a stainless steel polymerization vessel having an inner volume of 100 and equipped with a stirrer in the same manner as in Example 1. Aromatic amine compound condensate used in each experiment, sodium salt of sulfonated aromatic amine compound condensate, metal compound or inorganic colloid, and (a) component / (b) component / (c)
Table 3 shows the weight ratio of the components and the solvent used. However,
Experiment Nos. 36 to 42 did not apply the coating liquid, or (a)
It is a comparative example in which a coating liquid containing only one or two components selected from the component, the component (b) and the component (c) was applied.

Next, in a polymerization vessel coated in this way, 40 kg of water, 500 g of sodium oleate, 13 kg of polybutadiene latex (solid content 45%), 9.0 g of styrene, 5.0 g of acrylonitrile.
g, t-dodecyl mercaptan 40 g and cumene hydroperoxide 140 g were charged, and after raising the internal temperature to 65 ° C.,
Glucose (200 g), ferrous sulfate (2 g) and sodium pyrophosphate (100 g) were charged, and polymerization was carried out at 65 ° C. for 5 hours while stirring. After completion of the polymerization, the amount of polymer scale attached to the inner wall surface of the polymerization vessel was measured. The results are shown in Table 3.

[Effects of the Invention] According to the method of the present invention, it is possible to effectively prevent the adhesion of the polymer scale to the inner wall surface of the polymerization vessel or the like in the polymerization of a monomer having an ethylenic double bond, which has been difficult in the past. You can In particular, monomers with high solubility, such as styrene,
Adhesion of polymer scale can be prevented even in the case of polymerization of a polymerization system containing α-methylstyrene, acrylic ester, acrylonitrile and the like. By performing the coating once every several batches or ten or more batches, the polymerization vessel can be used repeatedly without adhering the polymer scale to the inner wall surface of the polymerization vessel.

Claims (1)

[Claims] 1. A method for preventing adhesion of a polymer scale in the polymerization of a monomer having an ethylenic double bond in a polymerization vessel, wherein the monomer contacts with the inner wall surface of the polymerization vessel during the polymerization. (A) at least one selected from an alkali metal salt and an ammonium salt of a sulfonate of an aromatic amine compound condensate, and (c) a metal compound and A method for preventing adhesion of polymer scale, which comprises performing the above-mentioned polymerization in a polymerization vessel coated with a coating solution containing at least one selected from inorganic colloids.