JPS61163902A - Scale deposition preventing agent - Google Patents

Abstract

PURPOSE:A scale deposition preventing agent for remarkably preventing polymer scale from depositing on the inside surface of a polymerization vessel, compris ing a reaction product of a liquid polybutadiene with a phenolic compound. CONSTITUTION:A scale deposition preventing agent is obtained by subjecting 1mol (in terms of unsaturated groups) of a normally liquid or semisolid polybutadiene of a MW of 200-100,000 and 0.5-5mol of a phenolic compound comprising pyrogallol and/or hydroxyhydroquinone to an alkylation reaction at 50-250 deg.C for 5min-1hr in the presence of a Friedel-Crafts catalyst in an inert gas atmosphere. The obtained agent is dissolved in a polar hydrocarbon solvent or an alkali solution, and applied to the inside surface of a polymeriza tion vessel at a coating weight of 0.01-10g/m<2> (solid matter).

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a scale adhesion inhibitor that prevents the adhesion of polymer scale that occurs on the inner surface of a polymerization reactor during, for example, the polymerization of vinyl monomers.

When a vinyl monomer is polymerized in the presence of a dispersant or emulsifier and a polymerization initiator, the inner surface of the polymerization reactor, that is, the inner wall thereof,
Solid polymers called scale often adhere to stirring blades, baffle plates, condensers, etc.

This scale causes a decrease in heat transfer efficiency, a decrease in product yield, a decrease in quality due to the contamination of exfoliated scale into the product, a decrease in productivity due to the labor and time required for removing the scale, and a decrease in productivity due to the wasted labor and time required for removing scale. This brings about many disadvantages, such as causing occupational safety and health problems.

[Prior Art] In order to solve these problems, many methods have been proposed to prevent scale formation and its adhesion to a polymerization vessel.

For example, dyes, pigments, other polar organic compounds,
There are methods of applying mW and its salts, polyvalent metal salts, etc. to the inner surface of the polymerization vessel or adding them to the aqueous medium, but these methods have problems with the sustainability of their effects and have problems with the various characteristics of the product. It has various disadvantages such as worsening of

As a method for improving these methods, a method has also been proposed in which a polymer compound having a functional group that prevents scale formation is coated on the inner surface of the polymerization vessel.

Phenolic compounds have conventionally been used as polymerization inhibitors, and many methods using them have been proposed.

For example, JP-A-55-16004 discloses a product in which a phenol/aldehyde initial condensate is reacted with nitrophenols, and U.S. Pat. No. 4,080,173 describes a self-condensed polyhydric phenol and naphthol,
JP-A-55-54317 discloses a condensate of a phenolic compound and an aromatic aldehyde;
No. 0 discloses alginate propylene glycol ester, JP-A-55-11209 discloses a nitrile-containing polymer, JP-A-58-204006 discloses a drying oil or a semi-drying oil, a phenol compound and, if necessary, an aldehyde. A method is disclosed in which a reaction product, etc., is applied to the inner surface of a polymerization vessel.

However, when these methods are used, there are many problems that need to be improved, such as a decrease in the polymerization rate and problems with the sustainability of the descaling effect due to insufficient durability of the coating film.

[Structure of the Invention] As a result of intensive research in order to eliminate these drawbacks, the present inventors have found that various organic polymers, especially when vinyl monomers are polymerized, are coated on the inner surface of a polymerization vessel and polymerized. The inventors have discovered that scale adhesion can be significantly prevented by carrying out the above steps, and have completed the present invention.

That is, the present invention relates to a scale adhesion inhibitor comprising a reaction product of liquid polybutadiene and a phenolic compound.

The liquid polybutadiene used in the inhibitor of the present invention is liquid or semi-solid at room temperature and has a molecular weight of 200 to 10G, G
oo Preferably, it is 300 to 10,000.

These liquid polybutadienes are produced by living anionic polymerization (H, Szwarc, Nature, 178.1168
(1956), H.

Szwarc, “Carbanion, Livin
a Polymer and Electron Tra
nsfer Processes tt, Inter
science 1Publisher In
c,, New York, N, Y, ) and coordination anionic polymerization (Japanese Patent Publication No. 46-20495. Japanese Patent Publication No. 48-43
084) and other known methods.

Liquid polybutadiene consists of 1.2 bonds, 1
．． There are two types of polybutadiene consisting of 4 bonds, both of which can be used in the present invention, but liquid polybutadiene consisting of 1,2 bonds is preferred.

Furthermore, liquid poly-1-tadiene having a hydroxyl group or carboxyl group at the end group, or partially modified with acid anhydride or oxygen can also be used.

The phenolic compound constituting the present invention is a compound having one or more phenolic 10HM in its aromatic compound.

For example, some phenols such as phenol and cresol,
resorcinol, catechol, hydroquinone.

Dihydric phenols such as bisphenol octa, pyrogallol,
Examples include trihydric phenols such as human oxyhydroquinone, and compounds having substituents such as alkyl groups and carboxylic acid groups on the above-mentioned compounds.

The method for producing the reaction product of liquid polybutadiene and a phenol compound of the present invention is to react liquid polybutadiene and a phenol compound using a Friedel-Crafts catalyst in a nitrogen atmosphere at 50 to 250°C, preferably at 100 to 180°C for 5 minutes to 1089i1 is produced by alkylation reaction for 1 to 5 hours.

Friedel-Crafts type catalysts include commonly used aluminum chloride, boron fluoride, and zinc chloride.

Halides such as iron chloride, complex compounds thereof, inorganic acids such as hydrochloric acid and sulfuric acid, and organic acids such as para-toluenesulfonic acid can be used.

The mixing ratio of liquid polybutadiene and phenol compound is 0.5 to 5 moles, preferably 0.8 to 2 moles of phenol compound per mole of unsaturated groups in liquid polybutadiene.
Mol is used. The liquid polybutadiene and the phenol compound can also be reacted by dissolving them in an inert solvent.

Further, Friedel-Crafts type catalyst is used in an amount of 0.01 to 100 parts of a mixture of liquid polybutadiene and a phenol compound.
10 parts, preferably 0.1 to 2 parts are used.

The descaling agent obtained by the reaction in this manner is used after being dissolved in a hydrocarbon polar solvent or an alkaline solution.

This solution is applied to the surface of the polymerization vessel at a rate of 0.01 to 10 g/m2 (as polymer) per square meter of the target polymerization vessel by a method such as a spray method or a rinsing method.

Polymerization of vinyl monomers using the present invention includes suspension polymerization,
Emulsion polymerization is employed. The dispersant used in this polymerization,
There are no particular restrictions on the emulsifier, initiator, etc., and commonly used ones can be used.

For example, dispersants and emulsifiers include protective colloidal compounds such as partially saponified polyvinyl acetate, acrylic acid copolymers, cellulose derivatives, gelatin, and starch, esters of higher fatty acids and polyhydric alcohols, and polyvinyl acetate. Anionic surfactants such as oxyethylene derivatives, metal salts of higher fatty acids, and metal salts of alkylbenzenesulfonic acids are used.

Benzoyl peroxide is used as a polymerization initiator.

Organic peroxides such as lauroyl peroxide and dioctyl peroxydicarbonate, azo compounds such as azobisisodimethylvaleronitrile, and persulfates such as ammonium persulfate are used.

The term "vinyl standard" as used herein refers to monomers forming vinyl groups, such as olefins such as ethylene and 10-pyrene, vinyl halides such as vinyl chloride and vinylidene chloride, and vinyl esters such as vinyl acetate. vinyl ethers such as ethyl vinyl ether, acrylic acid ethers such as methyl methacrylate, metal salts or esters such as maleic acid and fumaric acid, aromatic vinyls such as styrene, diene monomers such as butadiene, chlorobrene, isoprene, etc. Examples include acrylonitrile, acrylonitrile, etc.

Although the present invention can be used to polymerize the above-mentioned vinyl monomers alone or a mixture of two or more vinyl monomers, it is particularly effective in polymerizing monomers mainly composed of vinyl chloride. )
The present invention will be specifically explained below using Examples.

Example 1 A reaction product of liquid polybutadiene and a phenolic compound was produced by the following method using each component (A) and (8) as shown in Table 1, and applied to a polymerization vessel.

In a 4-ton flask with a stirrer, (^) liquid polybutadiene 1001; 1 (B) 200 g of phenolic compound,
Add 2g of anhydrous aluminum chloride and heat under nitrogen atmosphere for 15 minutes.
The reaction was carried out at 0°C for 3 hours. After the reaction was completed, the reactant was cooled to 90°C and washed with 40G++d pure water.

After washing, dehydration, and drying, a blackish brown reaction product soluble in methanol, acetone, and alkali was obtained. A 3x acetone solution of this reaction product was spray applied to a stainless steel polymerization vessel having a capacity of 1000 J, and then dried at 50° C. for 2 hours to remove acetone.

The coating amount was approximately 0.313/m.

In this polymerization vessel, 200 # of vinyl chloride and 400 Kl of pure water were added.
, 150 g of partially saponified polyvinyl acetate, and 609 g of azobisdimethylvaleronitrile were added, and polymerization was carried out at 51°C with stirring at 9 hours.

After the polymerization was completed, the amount of scale attached was measured, and the results shown in Table 1 were obtained.

For comparison, the results are also shown in the same table for examples in which the descaling agent was not applied (the polymerization conditions are the same as in the case in which the descaling agent was applied. The same applies to the following examples.) Examples 2 A reaction product of liquid polyphtadiene and a phenol compound was produced in the same manner as in Example 1, and after coating, polymerization was carried out under the following conditions.

In the same polymerization vessel as used in Example 1, add 190 ml of vinyl chloride,
9 to 10 parts of vinyl acetate, 9 to 450 parts of pure water, 180Q of partially saponified polyvinyl acetate, and 60 g of azobisdimethylvaleronitrile were added, and polymerization was carried out at 60°C for 10 hours with stirring.

After the polymerization was completed, the polymerization vessel was washed with water under a pressure of 5 atm, and the amount of scale was measured.

Table 2 shows the results.

Example 3 A reaction product of liquid polybutadiene and a phenol compound was produced in the same manner as in Example 1, and after coating, polymerization was carried out under the following conditions.

In the same polymerization vessel as in Example 1, 9 kg of O Robucin 200 and 8 kg of polyoxyethylene beef tallow alkylpropylene diamine
, vinegar m2Kg, alumina sol IKg, sodium formaldehyde sulfoxylate 0.04Kg, pure water 200
9 was added to the solution, and the polymerization was completed in 10 hours at 40° C. while adding 0.02 ICg of t-butyl hydroperoxide.

After polymerization, the polymerization vessel was washed with water under a pressure of 5 atm, and scale adhesion R was measured.

Table 3 shows the results.

Example 4 In Experiment No. 014 of Example 1, the polymerization vessel was washed with water after completion of polymerization, and then the same polymerization as in the same example was carried out in that state.

Repeated polymerization tests were conducted using this method to measure the amount of scale attached.

As a result, the amount of scale deposited after 30 batch polymerizations was approximately 1!, almost unchanged from the first polymerization! II
/m remained. - As a result of repeated polymerization tests in a polymerization vessel without applying the descaling agent of Rikiki's invention, 1
It was 100111/m at the time of the first polymerization, and it was necessary to remove the scale in order to carry out subsequent repeated polymerizations.

Table - Experiment No. (A) (B) Scale Liquid polyphenol Coating amount Butadiene Compound (o/Td) 1 Not applied 10021.2 Polyphenol 5 Butadiene (molecular weight 1050) 3 Resorcinol 24
Pyrogallol 151.4 poly
Pyrogallol 8-butadiene
j (molecular weight 1750) Table 3 Experiment No. (A) (8) Scale liquid polyphenol Coating amount Butadiene Compound (a/go) 1 Not applied 20021.2 Polyphenol 8 Butadiene (molecular weight 1G5G) 3 Resorcinol 54
Pyrogallol 151.4 poly
Birogal 0-L 20 Butadiene (molecular weight 175G) Table 3 Experiment No. (A) (B) Scale liquid polyphenol Coating amount Butadiene Compound (g/foot) 1 Not applied 5021.2 Polyphenol 15 Butadiene (Molecular weight, 1050 ) 3 〃Resorcinol 154
〃 Pyrogallol 1051.4 Poly
Pyrogallol 20 butadiene (molecular weight 175G)

Claims (1)

[Scope of Claims] 1) A scale adhesion inhibitor comprising a reaction product of liquid polybutadiene and a phenolic compound. 2) The scale adhesion inhibitor according to claim 1, wherein the liquid polybutadiene is 1,2 polybutadiene. 3) The scale adhesion inhibitor according to claim 1 or 2, wherein the phenolic compound is pyrogallol and/or hydroxyhydroquinone.