JPH0617364B2 - 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.

[Prior Art] In a method for producing a polymer by polymerizing a monomer in a polymerization vessel, there is known a problem 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 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 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 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, 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. Particularly, in the case of a stainless steel polymerization vessel, there is a problem that polymer scale is likely to adhere.

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 the two groups of specific compounds to the inner wall surface of the polymerization vessel in two steps.

That is, the present invention provides 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, which is intended to solve the above-mentioned problems. To the other portion in which the monomer contacts, in advance, first (a) a condensate of an aromatic compound is applied,
The present invention provides a method for preventing adhesion of a polymer scale, which comprises performing the above-mentioned polymerization in a polymerization vessel in which the (b) hydroxyl group-containing polymer compound is applied to the obtained coating film.

Examples of the condensate of the aromatic compound of the group (a) used in the present invention include, for example, an aromatic amine compound and an aromatic nitro compound described in JP-B-60-30681 in the presence of a condensation catalyst at 100 to A condensate obtained by reacting in the temperature range of 250 ° C, or a condensate obtained by forming a base with an alkali metal salt or an ammonium compound; JP-B-59-16561.
Straight-chain or branched-chain polyaromatic amines having a molecular weight of about 250 or more as described in JP-B No. 60-54323 and JP-B No. 60-54323;
(1) Self-condensation product of divalent or trivalent polyhydric phenol described in JP-B-62-3841; (2) Self-condensation product of divalent or trivalent polyhydric phenol of 2 or more. And (3) a condensation product selected from the group of self-condensation products of polyvalent naphthols; pyrogallol and an aldehyde containing a unit represented by the following general formula in the molecule described in JP-B-60-59246. Reaction products of (In the formula, R is a divalent hydrocarbon group, p and q are 0 or 1); Pyrogallol or hydroxyhydroquinone represented by the following general formula described in JP-A-57-192413 and aromatic aldehyde Condensate (In the formula, n represents 0 or an integer of 1 or more, and R represents hydrogen or a C _{1 to} C ₁₀ alkyl group); Aromatic diamine and aromatic quinone described in JP-A-61-7309 And a quinone-amine compound having an average molecular weight of 3000 or more obtained by subjecting and to an addition reaction in a solvent having a solubility parameter of 9.0 to 12.2 alone or in a mixed solvent containing an equal weight or less of an alcohol to the solvent, and separating by precipitation. Can be mentioned. These may be used alone or in combination of two or more.

Examples of the hydroxyl group-containing polymer compound in the group (b) include starches such as amylose, amylopectin, dextrin, oxidized starch, acetyl starch, nitrostarch, methyl starch, and carboxymethyl starch; and derivatives thereof; pectic acid, proto Hydroxyl group-containing plant qualities such as pectin, pectininic acid, alginic acid, laminarin, fucoidin, agar, carrageenin; hydroxyl-containing animal slime such as hyaluronic acid, chondroitin sulfate, hevalin, keratosulfate, chitin, caronin sulfate, limacoitin sulfate Nucleic acids such as ribonucleic acid and deoxyribonucleic acid; methyl cellulose, ethyl cellulose, carboxymethyl cellulose,
Glycol cellulose, benzyl cellulose, cyanoethyl cellulose, methylene ether of cellulose, triphenylmethyl cellulose, formyl cellulose, cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, cellulose ester sulfonate, cellulose ester carbamate, nitrocellulose, phosphorus Cellulose derivatives such as acid cellulose and cellulose xanthate; hemicelluloses such as xylan, mannan, alabogalactan, galactan, and araban; alcohol lignin, dioxane lignin, phenol lignin, hydrotrobic lignin, mercapto lignin, thioglycolic acid lignin, Lignin sulfonic acid, alkali lignin, thioalkali lignin, acid ligni , Copper oxide - ammonia lignin, such lignin periodate lignin; phenol - formaldehyde resins, partially saponified polyvinyl alcohol, polyvinyl alcohol and the like. These may be used alone or in combination of two or more. Among these, oxidized starch, acetyl starch, carboxy starch, pectic acid, glycol cellulose,
Lignin sulfonic acid, periodate lignin, methyl cellulose, cellulose phosphate and mercapto lignin are preferred.

In the method of the present invention, in order to form a coating film to prevent the adhesion of polymer scale on the inner wall surface of the polymerization vessel, first (a)
One or more condensates of the aromatic compounds of the group are applied to the inner wall surface of the polymerization vessel and other portions where the monomers come into contact during the polymerization, such as a stirring shaft and a stirring blade. This coating operation is carried out by dissolving one or more condensates of aromatic compounds 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. As a solvent for dissolving the condensate of the aromatic compound, methanol, ethanol, propanol, butanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol, 3-methyl-1.
-Alcohol solvents such as butanol, 2-methyl-2-butanol and 2-pentanol; aliphatic hydrocarbon solvents such as n-hexane and n-heptane; aromatic hydrocarbon solvents such as benzene, toluene and xylene. Methylene chloride, 1-chlorobutane, amyl chloride, dichloroethylene,
Halogenated hydrocarbon solvents such as 1,1,2-trichloroethane; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone; ester solvents such as methyl formate, ethyl formate, methyl acetate, methyl acetoacetate; 4-methyl Examples thereof include ether solvents such as dioxolane 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.

The concentration of the condensate of the aromatic compound in the coating liquid is not particularly limited as long as the coating amount described below can be obtained, but is usually 0.
001 to 5% by weight is preferable. The dry coating amount of the obtained coating film is usually preferably 0.001 to 5 g / m ² .

Next, the hydroxyl group-containing polymer compound of group (b) is applied onto the coating film of the condensation product of the aromatic compound of group (a) thus formed. This coating operation includes, for example, one or two or more of the required polymer compounds in a suitable solvent at about 0.
A coating solution is prepared by dissolving it in a concentration of 01 to 5.0% by weight, and the coating solution is applied to the coating surface of the condensate of the aromatic compound,
Then, it may be dried at room temperature to about 100 ° C.
It is necessary to form a coating film by sufficient drying. The temperature of the inner wall of the polymerization vessel (application temperature) during application is from room temperature to 100
It is about ℃. Examples of the solvent for dissolving the hydroxyl group-containing polymer compound include water and an organic solvent that is easily miscible with water, such as an alcohol solvent, an ester solvent, and a ketone solvent. Used alone or as a mixed solvent of two or more kinds. The dry coating amount of the coating film made of the hydroxyl group-containing polymer of group (b) thus obtained is usually 0.001 to 5 g / m ²
Is preferred.

In this way, after the two-step coating process is completed on the inner wall of the polymerization vessel and other portions where the monomer contacts during polymerization, the monomer having an ethylenic double bond is added to the polymerization vessel according to a conventional method. A polymerization initiator, other necessary 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, gen-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, suspending agents such as partially saponified polyvinyl alcohol, methyl cellulose and polyacrylate, solid dispersants such as calcium phosphate and hydroxyapatite, anionic emulsifiers such as sodium lauryl sulfate, sodium dodecylbenzene sulfonate, sodium dioctyl sulfosuccinate, sorbitan mono Nonionic emulsifiers such as laurate and polyoxyethylene alkyl ether,
Fillers such as calcium carbonate and titanium oxide, tribasic lead sulfate, calcium stearate, dibutyltin dilaurate, stabilizers such as dioctyltin mercaptide, lubricants such as rice wax and stearic acid, DOP, DB
Plasticizers such as P, trichlorethylene, chain transfer agents such as mercaptans, pH adjusters, diisopropyl peroxydicarbonate, α, α'-azobis-2,4-dimethylvaleronitrile, lauroyl peroxide, potassium persulfate, cumene Even in a polymerization system in which a polymerization catalyst such as hydroperoxide or p-menthane hydroperoxide 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 Condensation Product of Aromatic Compound (1) Production of Condensation Product NO.1 aniline 1.00 mol, hydrochloric acid 0.310 mol, nitrobenzene 0.2
A mixture of 27 mol and 0.103 mol of ferric chloride at 60 ° C
After heating for 6 hours at 180 ° C., the temperature was raised to 180 to 185 ° C. to distill off water, and the temperature was maintained for 15 hours to carry out the reaction. Aniline and nitrobenzene were distilled out along with water during the reaction. Distilled aniline and nitrobenzene were recovered and 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,
It was dried to obtain a condensate.

(2) Production of condensate NO.2 A mixture of 1.00 mol of m-phenylenediamine, 1.00 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) Production of Condensate No. 3 Pyrogallol (3 mol) was dissolved in water (2), benzaldehyde (2 mol) and phosphoric acid (6 mol) were added, and the mixture was reacted at 100 ° C. for 4 hours.

The obtained reaction mixture was filtered, washed with hot water 5 to 6 times to remove excess phosphoric acid, and dried to obtain a condensate.

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, the condensate produced in the above Production Example was dissolved in methanol to a concentration of 0.5% by weight to prepare a coating liquid [coating liquid A]. It was applied to the contacting part, left at 50 ° C. for 15 minutes, dried and washed with water. Next, a coating liquid [coating liquid B] prepared by dissolving a hydroxyl group-containing polymer compound in water was applied, dried and washed with water. Table 1 shows the condensate used in each experiment, the hydroxyl group-containing polymer, the concentration of the coating liquid B, and the coating and drying conditions. However, Experiments Nos. 1 to 3 are comparative examples in which the coating liquid was not applied or only the coating liquid A or B was applied.

After that, 400 k of water was added to the polymerization vessel coated in this way.
g, 260 kg of styrene, 140 kg of acrylonitrile, 400 g of partially saponified polyacrylamide and 1.2 kg of α, α'-azobisisobutyronitrile, and at 90 ° C with stirring
It was polymerized for 5 hours. 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 1.

Example 2 A coating solution A was applied to a stainless steel polymerization vessel equipped with a stirrer with an internal volume of 1000 by the same method as in Example 1, and then a coating solution B was applied. The condensate used in each experiment, the hydroxyl group-containing polymer compound of the coating liquid B, and the concentration of the coating liquid B,
The coating and drying conditions are shown in Table 2. However, Experiment No. 1
Nos. 6 to 18 are comparative examples in which the coating solution was not applied or only one of the coating solutions A and B was applied. Next, 40 kg of water, 500 g of sodium oleate, and Polybutadiene latex (solid content 45%) 13kg, styrene 9.0kg, acrylonitrile
5.0 kg, 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 then at 65 ° C. while stirring, 5 Polymerization was carried out for a time. 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 2.

[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 the 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 in every batch or once in several 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 the inner wall surface of the polymerization vessel and the polymerization. To the other part, in advance, first apply (a) a condensate of an aromatic compound,
Next, a method for preventing the adhesion of a polymer scale, which comprises performing the above-mentioned polymerization in a polymerization vessel in which (b) a hydroxyl group-containing polymer compound is applied to the obtained coating film.