JPH07247304A - Polymerizer and production of polymer therewith - Google Patents

Abstract

PURPOSE:To obtain a polymerizer which prevents polymer scale deposition even when repeatedly used for the polymn. of an ethylenically unsatd. monomer by coating the polymerizer with a specific layer. CONSTITUTION:At least a part of the surface in contact with a reaction mixture in a polymerizer for polymerizing an ethylenically unsaid. monomer of the formula: CH2=CXY [wherein X is H or methyl; and Y is H, alkyl, -COOH, -COOM (wherein M is an alkali metal or an ammonium), -COOR (wherein R is alkly), -OCOR,-OR, -CN, -C6H4Z (wherein Z is H,-OH=CH2, or-CH=CH2 or -CH=CH2] is coated with a layer of gold or an alloy contg. at least 50wt.% gold. The surface includes the inner wall surface of the polymerizer and the outer and/or the inner surfaces of instruments installed in the polymerizer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymerization vessel for polymerizing a monomer having an ethylenically unsaturated double bond and a method for producing a polymer using the polymerization vessel.

[0002]

2. Description of the Related Art In a method for 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.

When the polymer scale adheres to the inner wall surface of the polymerization vessel, the yield of the polymer, the cooling ability of the polymerization vessel and the like are deteriorated, and the polymer scale is peeled off and mixed into the polymer. There is a disadvantage that the quality of the molded product obtained by molding the coalescence is lowered. Also,
In order to remove the adhered polymer scale, not only excessive labor and time is required, but also unreacted monomer is contained in this polymer scale, which has become a very serious problem in recent years. There is a risk of personal injury due to existing monomers.

Conventionally, in the polymerization of a monomer having an ethylenically unsaturated double bond, as a method for preventing the adhesion of the polymer scale to the inner wall surface of the polymerization vessel, a suitable substance is a polymer scale adhesion preventive agent. As a known method, a method of applying to the inner wall surface of the polymerization vessel or the like is known.

[0005]

However, the method of applying the polymer scale anti-adhesion agent shows the polymer scale anti-adhesion effect when the polymerization is repeated for about 3 to 4 batches, but the number of polymerization batches is more than that. When the number of polymerization units increases, for example, the tip and inner surface of the raw material charging nozzle, the stirring shaft, the stirring blade, the rod-shaped temperature sensor, the inner surface of the reflux condenser, the welded portion of the inner wall of the polymerization unit, the baffle, the inner surface of the valve, etc. In some cases, adhesion and growth of polymer scale may be observed in the area where the reaction mixture comes into contact.

The monomer having an ethylenically unsaturated double bond to be polymerized is represented by the following general formula (1): CH ₂ ═CXY (1) [wherein, X is a hydrogen atom or a methyl group. , Y is a hydrogen atom, an alkyl group or a formula: —COOH, —COOM (where M is an alkali metal or ammonium ion), —COOR
(Where R is an alkyl group; the same applies hereinafter), -OCOR,
--OR, --CN, --C ₆ H ₄ Z (where Z is a hydrogen atom or --OH,
A group represented by -CH ₃ or -CH = CH _2. ) Or a group represented by —CH═CH ₂ . ] In the case of a monomer represented by the following, depending on the type of polymer scale anti-adhesive agent, these monomers have the ability to dissolve in a coating film formed by applying the inhibitor. In some cases, it may not be possible to obtain the desired scale adhesion prevention effect. In particular, styrene, α-methylstyrene, acrylic acid ester, acrylonitrile, vinyl acetate and the like generally have a very large dissolving ability with respect to the coating film, so that the desired scale adhesion preventing effect cannot be obtained. Further, particularly when a stainless steel polymerization vessel is used, the polymer scale is likely to adhere.

Accordingly, the object of the present invention is to solve the above-mentioned general formula (1)
In the polymerization of a monomer having an ethylenically unsaturated double bond represented by the following, a polymerization vessel in which adhesion of a polymer scale is prevented even when the polymerization is repeated, and a method for producing a polymer using the polymerization vessel To provide.

[0008]

The present invention has the following general formula:
(1): CH ₂ = CXY (1) [wherein, X is a hydrogen atom or a methyl group, Y is a hydrogen atom, an alkyl group or a formula: -COOH, -COOM (where M is an alkali metal or ammonium ion) ), −COOR
(Where R is an alkyl group; the same applies hereinafter), -OCOR,
--OR, --CN, --C ₆ H ₄ Z (where Z is a hydrogen atom or --OH,
A group represented by -CH ₃ or -CH = CH _2. ) Or a group represented by —CH═CH ₂ . ] In the polymerization reactor for the polymerization of a monomer having an ethylenically unsaturated double bond represented by the following, at least a part of the portion in contact with the reaction mixture in the polymerization reactor is a film made of gold or a gold-based alloy. A polymerizer characterized by being coated is provided.

The present invention also has the following general formula (1): CH ₂ = CXY (1) [wherein X is a hydrogen atom or a methyl group, Y is a hydrogen atom, an alkyl group or the formula: -COOH, -COOM (where M is an alkali metal or ammonium ion), -COOR
(Where R is an alkyl group; the same applies hereinafter), -OCOR,
--OR, --CN, --C ₆ H ₄ Z (where Z is a hydrogen atom or --OH,
A group represented by -CH ₃ or -CH = CH _2. ) Or a group represented by —CH═CH ₂ . ] A method for producing a polymer by polymerizing a monomer having an ethylenically unsaturated double bond represented by the following in the polymerization vessel, wherein the reaction vessel in the polymerization vessel is in contact with the reaction mixture in the polymerization vessel: At least a part has a step of performing the polymerization using a polymerization vessel covered with a film made of gold or a gold-based alloy,
This provides a manufacturing method in which adhesion of polymer scale is prevented.

According to the polymerization vessel the present invention, when performing the polymerization of monomers represented by the general formula (1), part of the reaction mixture in the polymerization vessel is in contact,
Specifically, the inner wall surface of the polymerization vessel, and, for example, the surface of the stirring shaft, the surface of the stirring blade, the surface of the baffle, the inner surface of the reflux condenser, the surface of the temperature sensor, the surface and the inner surface of the nozzle for charging raw materials, the valve, etc. The adhesion of the polymer scale can be prevented by forming a film made of gold or a gold-based alloy on at least a part of the surface and / or the inner surface of the equipment provided in the polymerization vessel such as the inner surface.

According to the research conducted by the present inventors,
Welded portion of inner wall of polymerization vessel, tip and inner surface of nozzle for charging raw materials, near interface between gas phase and liquid phase of stirring shaft, tip of stirring blade, surface of temperature sensor, inner surface of reflux condenser,
It has been found that polymer scale is likely to adhere to the surface of the baffle and the inner surface of the valve. It is considered that the scale is likely to adhere to these portions because the reaction mixture easily stays and the contact time becomes long. Therefore, it is preferable to form a film made of gold or a gold-based alloy on at least one of these portions. More preferably, the film is formed on all of these particularly scale-prone portions. Further, most effectively, it is preferable to form the film on all the portions where the reaction mixture comes into contact.

The reason why the polymer scale can be prevented from adhering by forming a film made of gold or a gold-based alloy in this way is probably that the gold-based alloy is inert to the reaction mixture and is resistant to the reaction mixture. It is considered that this is because it has corrosiveness, and a smooth surface is formed to reduce surface irregularities.

The gold-based alloy means an alloy containing 50% by weight or more of gold, for example, Au-Co alloy, Au-Ni alloy, Au-
Co-Ni alloy etc. are mentioned. The gold content in these gold-based alloys is preferably 70% by weight or more, and more preferably 90 to 99.5% by weight. If the gold content is too low, the effect of preventing polymer scale from adhering is reduced.

The thickness of the film made of gold or gold-based alloy is preferably 0.01 to 3 μm, more preferably 1 to 3 μm.
μm.

As a method for forming a film made of gold or a gold-based alloy, for example, an electroplating method, an electrodeless plating method,
A general method such as a hot dip plating method, a vacuum deposition method, a metal infiltration method, and a metallikon method may be used.

Further, in order to improve the adhesiveness of the film made of the above gold or gold-based alloy, the part where the film is formed is
Appropriate pretreatment depending on the technique used, for example washing the surface with water,
It is preferable to perform ultrasonic treatment, polishing treatment, surface treatment with an alkaline substance such as sodium hydroxide.

When there is a portion where the coating made of gold or a gold-based alloy is not formed despite the contact of the reaction mixture, the portion is preferably polished. The polishing method is not particularly limited, and for example, buff polishing,
Examples of the method include immersion electrolytic polishing and electrolytic composite polishing.

The surface roughness of the polished surface preferably has a maximum height R _max of 1 μm or less.
It is preferably 0.7 μm or less. Most preferably,
The maximum height R _max is 1 μm or less and the center line average roughness _Ra is
It is preferably 0.2 μm or less. Maximum height R above
_{The max} and centerline average roughness _Ra are defined in JIS B 0601.

As the polymerization vessel in the present invention, a conventionally known type equipped with a stirrer, a reflux condenser, a baffle, a jacket and the like can be used. As the stirrer, a stirrer of the type such as a paddle, a Fowler, a blue margin, a propeller, and a turbine is used, if necessary, in combination with a baffle such as a flat plate, a cylinder, a hairpin coil or the like.

From the viewpoint of heat transfer and corrosion resistance, the material of the portion which comes into contact with the reaction mixture such as the polymerization vessel, the reflux condenser, the baffle, the valve, etc. is 18-8 austenite type, 13 chromium ferrite type-martensite type, 18 chromium ferrite type. ,
It is preferable to use stainless steel such as high chromium ferrite type, two-phase austenite / ferrite type, etc., and the film made of the above gold or gold-based alloy is formed on the portion using such material. Further, a conventionally known scale inhibitor may be applied to these portions or may be added to the reaction mixture.

Polymerization Polymerization of the monomer represented by the general formula (1) is carried out by a conventional method using the polymerization vessel in which the gold-based alloy is formed as described above. That is, in addition to the monomer represented by the general formula (1) and the polymerization initiator (catalyst), if necessary, a polymerization medium such as water, a suspending agent, a solid dispersant, a nonionic agent, an anion agent. A dispersant such as a hydrophilic emulsifier is charged, and then polymerization is performed by a conventional method.

Examples of the monomer represented by the above general formula (1) for carrying out the polymerization by applying the method of the present invention include vinyl esters such as vinyl acetate and vinyl propionate; acrylic acid, methacrylic acid, and These esters and salts; for example, diene-based monomers such as butadiene, chloroprene and isoprene; styrene; acrylonitrile; α-methylstyrene; vinyl ether and the like.

The type of polymerization to which the method of the present invention is applied is not particularly limited, and suspension polymerization, emulsion polymerization, solution polymerization,
It is effective in both bulk polymerization and vapor phase polymerization.

A general polymerization method will be specifically described below by taking suspension polymerization and emulsion polymerization as examples. First,
Water and a dispersant are charged into a polymerization vessel, and then a monomer is charged. At this time, the internal pressure of the polymerization vessel is usually 0 to 10 kgf / cm ² ·
Become G Further, the polymerization initiator is charged before and / or after charging the monomer. Then, polymerization is carried out at a reaction temperature of 30 to 150 ° C. During the polymerization, one or more kinds of water, a dispersant and a polymerization initiator are added, if necessary. Also,
The reaction temperature at the time of polymerization depends on the kind of the monomer to be polymerized. For example, in the case of styrene, the polymerization is carried out at 50 to 150 ° C. The polymerization is judged to be completed when the desired reaction rate is reached (usually, the reaction rate is 80 to 100%). Water charged during polymerization, a dispersant and a polymerization initiator are usually monomers.
About 100 to 100 parts by weight of water, about 50 to 500 parts by weight of water and about 0 of a dispersant.
The amount is 01 to 30 parts by weight, and the polymerization initiator is about 0.01 to 5 parts by weight.

In the case of solution polymerization, an organic solvent such as toluene, xylene or pyridine is used as a polymerization medium instead of water. A dispersant is used as needed.
Other polymerization conditions are generally the same as those for suspension polymerization and emulsion polymerization.

In the case of bulk polymerization, the inside of the polymerization vessel is replaced with nitrogen gas, or after evacuation to a pressure of about 0.01 to 760 mmHg, the monomer and the polymerization initiator are charged into the polymerization vessel,
Polymerize at a reaction temperature of 10 to 250 ° C. For example, in the case of styrene polymerization, it is carried out at 50 to 150 ° C.

The substances added to the polymerization system can be used without any restrictions. That is, for example, t-
Butyl peroxy neodecanoate, bis (2-ethylhexyl) peroxydicarbonate, 3,5,5-trimethylhexanoyl peroxide, α-cumylperoxy neodecanoate, cumene hydroperoxide, cyclohexanone peroxide, t-butyl peroxypivalate, bis (2-ethoxyethyl) peroxydicarbonate, benzoyl peroxide, lauroyl peroxide, 2,4-dichlorobenzoyl peroxide, diisopropyl peroxydicarbonate, α, α′-azo Bisisobutyronitrile, α, α '
-Azobis-2,4-dimethylvaleronitrile, potassium peroxodisulfate, ammonium peroxodisulfate,
Polymerization initiators such as p-menthane hydroperoxide; for example, partially saponified polyvinyl alcohol, polyacrylic acid, copolymers of vinyl acetate and maleic anhydride, cellulose derivatives such as hydroxypropylmethyl cellulose, natural or synthetic polymers such as gelatin. Suspending agents such as compounds; solid dispersing agents such as calcium phosphate, hydroxyapatite; nonionic emulsifiers such as sorbitan monolaurate, sorbitan trioleate, polyoxyethylene alkyl ethers; sodium lauryl sulfate, dodecylbenzene sulfone Anionic emulsifiers such as sodium alkylbenzene sulfonates such as sodium acidate and sodium dioctylsulfosuccinates; for example, fillers such as calcium carbonate and titanium oxide;
For example, stabilizers such as tribasic lead sulfate, calcium stearate, dibutyltin dilaurate, dioctyltin methylcaptide; lubricants such as rice wax, stearic acid, cetyl alcohol; plasticizers such as DOP, DBP; -Mercaptans such as dodecyl mercaptan, chain transfer agents such as trichlorethylene; pH
Even in a polymerization system in which a regulator or the like is present, the method of the present invention can effectively prevent the adhesion of polymer scale.

Particularly suitable polymerizations using the polymerization vessel of the present invention include, for example, copolymerization of acrylonitrile and styrene by a suspension polymerization method using a solid dispersant, emulsion polymerization in the production of a vinyl acetate emulsion, and styrene. Emulsification in the production of copolymers of acrylic acid with acrylic acid or its esters, copolymers of styrene with methacrylic acid or its esters, polystyrene, ABS copolymer resins, and synthetic rubbers such as SBR, NBR, CR, IR, IIR. Polymerization or suspension polymerization may be mentioned.

Further, according to the present invention, the formed film made of gold or a gold-based alloy has high durability, and the effect of preventing adhesion of the polymer scale is maintained even if the polymerization is continuously carried out. Therefore, if the film is formed before the start of the first polymerization, the adhesion of the polymer scale can be prevented even if the polymerization is repeatedly performed.

[0030]

EXAMPLES Hereinafter, specific embodiments of the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Example 1 As a polymerization vessel, the internal volume was 20 liters and the material was SUS31
No. 6 and one-stage Faudra stirring blade, flat plate baffle 2
A polymerization vessel equipped with one sheet, two raw material charging nozzles, and one rod-shaped temperature sensor was used.

The portion of the polymerization vessel where the polymer scale is likely to adhere, that is, the surfaces of the stirring blade, the baffle and the rod-shaped temperature sensor, and the tip and inner surface of the nozzle are buffed to obtain the center line average roughness _Ra. 0.06 μm, maximum height R _max
After adjusting the thickness to 0.5 μm, a gold-based alloy film was formed. The film is
Formed by electroplating method, Au-Co alloy coating (film thickness 2μ
m, gold content 90% by weight).

Polymerization was carried out as follows using the above-mentioned polymerization vessel. In a polymerization vessel, styrene 4 kg, acrylonitrile 2.7 kg, water 7 kg, hydroxyapatite 135 g, sodium lauryl sulfate 2.7 g, t-dodecyl mercaptan 20 g
, And lauroyl peroxide (27 g) were charged, and the mixture was stirred at 70 ° C. for 1 hour. Next, the obtained reaction mixture was heated to 80 ° C. over 2 hours and then reacted at 80 ° C. for 1 hour. After the reaction was completed, the produced polymer and unreacted monomer were recovered and the inside of the polymerization vessel was washed with water.

The above polymerization and washing with water in the polymerization vessel were carried out in 1
As a batch, the same operation was repeated 5 batches. After the end of 5 batches, use a stainless steel spatula to remove the scale adhered to the part where the gold-based alloy film is formed (the surface of the stirring blade, the baffle and the rod-shaped temperature sensor and the tip and inner surface of the nozzle) so as not to damage the gold-based alloy film. It was scraped as completely as possible with the naked eye and weighed. The results are shown in Table 1.

Comparative Example 1 In this comparative example, an Example was used except that a polymerization vessel in which a gold-based alloy coating was not formed on the surfaces of the stirring blade, the baffle and the rod-shaped temperature sensor and the tip and inner surface of the nozzle was used as the polymerization vessel. Polymerization and washing with water in the polymerization vessel were carried out in 5 batches in the same manner as in 1. After the completion of 5 batches, the scale attached to the surfaces of the stirring blade, the baffle and the rod-shaped temperature sensor and the tip and inner surface of the nozzle were weighed in the same manner as in Example 1. The results are shown in Table 1.

Example 2 Polymerization was carried out as follows using the same polymerization vessel as that used in Example 1. Styrene 6 kg, polybutadiene rubber 720 g, mineral oil (made by Idemitsu Kosan Co., CP
-50) 480g and n-dodecyl mercaptan 6kg 115
Prepolymer prepared by reacting at 5 ° C for 5 hours 7 kg, water 7 kg, hydroxyapatite 70 g, sodium dodecylbenzenesulfonate 0.14 g, benzoyl peroxide
17.5 g and 10.5 g of t-butyl perbenzoate were charged into a polymerization vessel and reacted at 92 ° C for 3.5 hours, and then at 135 ° C for 1 hour.
Reacted for hours. After the reaction was completed, the produced polymer and unreacted monomer were recovered, and the inside of the polymerization vessel was washed with water.

The above-mentioned polymerization and washing with water in the polymerization vessel were carried out in 1
As a batch, the same operation was repeated 5 batches. After the completion of 5 batches, the scale attached to the portion where the gold-based alloy coating was formed was weighed in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2 In this Comparative Example, 5 batches of polymerization and washing in the polymerization vessel were carried out in the same manner as in Example 2 except that the polymerization vessel used in Comparative Example 1 was used as the polymerization vessel. After the completion of 5 batches, the scale attached to the surfaces of the stirring blade, the baffle and the rod-shaped temperature sensor and the tip and inner surface of the nozzle were weighed in the same manner as in Example 1. The results are shown in Table 1.

Example 3 Polymerization was carried out as follows using the same polymerization vessel as that used in Example 1. 8 kg of water, 5.2 kg of styrene, 2.8 kg of methacrylic acid, 8 g of partially saponified polyacrylamide and 24 g of α, α'-azobisisobutyronitrile were charged in a polymerization vessel and reacted at 90 ° C for 5 hours. After the reaction was completed, the produced polymer and unreacted monomer were recovered, and the inside of the polymerization vessel was washed with water.

The above polymerization and washing with water in the polymerization vessel were carried out in 1
As a batch, the same operation was repeated 5 batches. After the completion of 5 batches, the scale attached to the portion where the gold-based alloy coating was formed was weighed in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 3 In this Comparative Example, 5 batches of polymerization and washing in the polymerization vessel were carried out in the same manner as in Example 3 except that the polymerization vessel used in Comparative Example 1 was used. After the completion of 5 batches, the scale attached to the surfaces of the stirring blade, the baffle and the rod-shaped temperature sensor and the tip and inner surface of the nozzle were weighed in the same manner as in Example 1. The results are shown in Table 1.

Example 4 Polymerization was carried out as follows using the same polymerization vessel as that used in Example 1. After charging 9 kg of water, 225 g of sodium dodecylbenzenesulfonate, 12 g of t-dodecyl mercaptan and 13 g of potassium peroxodisulfate into the polymerization vessel, the inside of the polymerization vessel was replaced with N ₂ gas, and then 1.3 kg of styrene and 3.8 parts of butadiene. 20 kg at 50 ℃ with charging
Reacted for hours. After the reaction was completed, the produced polymer and unreacted monomer were recovered, and the inside of the polymerization vessel was washed with water.

The above polymerization and washing with water in the polymerization vessel were carried out in 1
As a batch, the same operation was repeated 5 batches. After the completion of 5 batches, the scale attached to the portion where the gold-based alloy coating was formed was weighed in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 4 In this Comparative Example, polymerization and washing with water in the polymerization vessel were performed in 5 batches in the same manner as in Example 4 except that the polymerization vessel used in Comparative Example 1 was used as the polymerization vessel. After the completion of 5 batches, the scale attached to the surfaces of the stirring blade, the baffle and the rod-shaped temperature sensor and the tip and inner surface of the nozzle were weighed in the same manner as in Example 1. The results are shown in Table 1.

Example 5 Polymerization was carried out as follows using the same polymerization vessel as that used in Example 1. 2.6 kg of polybutadiene latex (solid content: 45% by weight), 8 kg of water in the polymerization vessel
Then, 100 g of sodium oleate, 1.8 kg of styrene, 1 kg of acrylonitrile, 8 g of t-dodecyl mercaptan and 28 g of cumene hydroperoxide were charged, and the temperature in the polymerization vessel was raised to 65 ° C., and then 40 g of glucose and the first sulfuric acid sulfate were added. iron
0.4 g and 20 g of sodium pyrophosphate were charged and reacted at 65 ° C. for 5 hours. After the reaction was completed, the produced polymer and unreacted monomer were recovered, and the inside of the polymerization vessel was washed with water.

The above-mentioned polymerization and washing with water in the polymerization vessel were carried out in 1
As a batch, the same operation was repeated 5 batches. After the completion of 5 batches, the scale attached to the portion where the gold-based alloy coating was formed was weighed in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 5 In this Comparative Example, 5 batches of polymerization and washing in the polymerization vessel were carried out in the same manner as in Example 5 except that the polymerization vessel used in Comparative Example 1 was used as the polymerization vessel. After the completion of 5 batches, the scale attached to the surfaces of the stirring blade, the baffle and the rod-shaped temperature sensor and the tip and inner surface of the nozzle were weighed in the same manner as in Example 1. The results are shown in Table 1.

Example 6 A polymerization vessel having an internal volume of 20 liters and a material of SUS31
No. 6 and one-stage Faudra stirring blade, flat plate baffle 2
A polymerization vessel equipped with one sheet, two raw material charging nozzles, and one rod-shaped temperature sensor was used.

All parts in this polymerization vessel, that is, the inner wall surface of the polymerization vessel, the stirring blade, the baffle and the rod-shaped temperature sensor, and the tip and inner surface of the nozzle were buffed to have a center line average roughness R _a of 0.06. After setting μm and maximum height R _max to 0.5 μm, a gold-based alloy film was formed. The coating is formed by electroplating and is an Au-Co alloy coating (coating thickness 2 μm, gold content 90% by weight).

Polymerization was carried out as follows using the above-mentioned polymerization vessel. A polymerization vessel was charged with 430 g of polyvinyl alcohol (polymerization degree: 1750, saponification degree: 88%) dissolved in 8 kg of water, the temperature inside the polymerization vessel was raised to 65 ° C, and then 360 g of vinyl acetate and peroxodiene were added. 40g potassium sulfate 4g water
What was melt | dissolved in was charged and it was made to react for 30 minutes. Subsequently, the temperature inside the polymerization vessel was raised to 75 ° C, 4.5 kg of vinyl acetate and 10 g of potassium peroxodisulfate dissolved in 100 g of water were added simultaneously over 3 hours, and then the temperature inside the polymerization vessel was increased. Was heated to 80 ° C. and reacted for 1 hour. After the reaction was completed, the produced polymer and unreacted monomer were recovered, and the inside of the polymerization vessel was washed with water.

The above polymerization and washing with water in the polymerization vessel were carried out in 1
As a batch, the same operation was repeated 5 batches. The scale adhered to the inner wall surface of the polymerization vessel after completion of 5 batches was measured in Example 1
Weighed in the same manner as. The results are shown in Table 1.

Comparative Example 6 In this Comparative Example, 5 batches of polymerization and washing in the polymerization vessel were carried out in the same manner as in Example 6 except that the polymerization vessel used in Comparative Example 1 was used as the polymerization vessel. After the completion of 5 batches, the scale attached to the inner wall surface of the polymerization vessel was weighed in the same manner as in Example 1. The results are shown in Table 1.

[0052]

[Table 1] Examples 1 to 5 and Comparative Examples 1 to 5: Polymer scale adhesion amount on the surfaces of the stirring blade, the baffle and the rod-shaped temperature sensor, and the tip and inner surface of the nozzle. Example 6 and Comparative Example 6: Adhesion amount of polymer scale on the inner wall surface of the polymerization vessel.

[0053]

INDUSTRIAL APPLICABILITY According to the present invention, in the polymerization of a monomer having an ethylenically unsaturated double bond such as styrene, α-methylstyrene, acrylic ester, acrylonitrile and vinyl acetate, various conditions such as a polymerization method are used. Regardless, the polymer scale can be effectively prevented from adhering even if the polymerization is repeated.

Claims (4)

[Claims] 1. The following general formula (1): CH ₂ ═CXY (1) [wherein, X is a hydrogen atom or a methyl group, Y is a hydrogen atom, an alkyl group or a formula: —COOH, —COOM (here And M is an alkali metal or ammonium ion), -COOR
(Where R is an alkyl group; the same applies hereinafter), -OCOR,
--OR, --CN, --C ₆ H ₄ Z (where Z is a hydrogen atom or --OH,
A group represented by -CH ₃ or -CH = CH _2. ) Or a group represented by —CH═CH ₂ . ] In the polymerization reactor for the polymerization of a monomer having an ethylenically unsaturated double bond represented by, at least a part of the portion in contact with the reaction mixture in the polymerization reactor is a film made of gold or a gold-based alloy. A polymerization vessel characterized by being coated. 2. The polymerization vessel according to claim 1, wherein the inner wall surface of the polymerization vessel is covered with a film made of gold or a gold-based alloy. 3. The polymerization vessel according to claim 1, wherein at least a part of the surface and / or the inner surface of the equipment provided in the polymerization vessel is covered with a film made of gold or a gold-based alloy. 4. The following general formula (1): CH ₂ ═CXY (1) [wherein, X is a hydrogen atom or a methyl group, Y is a hydrogen atom, an alkyl group or a formula: —COOH, —COOM (here And M is an alkali metal or ammonium ion), -COOR
(Where R is an alkyl group; the same applies hereinafter), -OCOR,
--OR, --CN, --C ₆ H ₄ Z (where Z is a hydrogen atom or --OH,
A group represented by -CH ₃ or -CH = CH _2. ) Or a group represented by —CH═CH ₂ . ] A method for producing a polymer by polymerization in a polymerization vessel of a monomer having an ethylenically unsaturated double bond represented by the above, wherein the reaction vessel in the polymerization vessel contacts the reaction mixture in the polymerization vessel. A production method comprising the step of carrying out the above-mentioned polymerization using a polymerization vessel at least a part of which is coated with a film made of gold or a gold-based alloy, whereby adhesion of polymer scale is prevented.