JP3129111B2 - Method for producing vinyl chloride polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a vinyl chloride polymer, and more particularly, to a method for producing a vinyl chloride polymer of high quality.
The present invention relates to a method for producing a vinyl chloride polymer which can be produced with high productivity.

[0002]

2. Description of the Related Art In general, a vessel used for a polymerization reaction of vinyl chloride or a mixture of copolymerizable monomers mainly composed of vinyl chloride (hereinafter collectively referred to as "vinyl chloride-based monomer") is a vessel. The main body 1 'is formed of a pressure-resistant closed container in which a dish-shaped end plate is welded to both ends of a cylindrical body, and a jacket 18 for removing heat or heating the contents is provided.
An outer jacket type tank container (FIG. 5) attached to the outside of the container body 1 'is used.

[0003] In this type of vessel, in order to maintain the pressure resistance in the vessel body, the vessel thickness is generally increased, the heat conductivity through the vessel body wall is low, and a vinyl chloride-based unit which is an exothermic reaction is produced. In the polymerization of monomer, it has been difficult to obtain high productivity. Further, when the size of the vessel container is increased, it is necessary to increase the thickness of the wall of the vessel body from the viewpoint of strength, and there is a disadvantage that the thermal conductivity is further reduced.

In order to solve this disadvantage due to heat conduction, as shown in FIG. 6, partitioning plates 19 are arranged side by side at right angles to the inner surface of the container body 1 ', and between the leading ends of the partitioning plates 19. An inner jacket system in which a flow path 21 partitioned by a partition plate 19 is formed between the inner strip 20 and the inner surface of the container main body 1 'by straddling the inner strip 20 (Japanese Patent Laid-Open No. 57-147502). ) Has been proposed.

[0005] However, although the inner jacket type vessel is excellent in heat conductivity, a large number of welds between the inner strips 20 are formed on the inner surface of the vessel in contact with the contents during the polymerization reaction of the vinyl chloride monomer. There are disadvantages due to being exposed on the surface. In other words, the welded portion has a surface roughness that is inevitably large due to its construction, and a weld defect is present. However, in the polymerization reaction of the vinyl chloride monomer, if the surface roughness of the portion in contact with the reaction mixture is rough, the polymer If the scale easily adheres and the generated scale peels and mixes into the product, the quality deteriorates (especially when processed into a film, etc.
Unmelted matter remains in the film, which causes so-called fish eye (FE). In order to prevent the adhesion of polymer scale, which causes deterioration in quality, production and maintenance of equipment, such as extremely smoothing a large number of welding lines and introducing special adhesion prevention / removal technology, are required. However, there is an inconvenience that the cost is increased.

In addition, in the polymerization reaction of a vinyl chloride monomer, stainless steel is usually used as a material for the inner surface of the vessel because of corrosion caused by hydrogen chloride generated as the reaction proceeds. When the polymerization reaction of vinyl chloride monomer is carried out using an inner jacket type tank vessel where a large number of welding lines are adjacent to the inner surface of the vessel, the residual stress due to welding is concentrated. There is a concern about stress corrosion cracking due to hydrogen chloride (chlorine ion) generated as a result. For this reason, it is necessary to carefully and continuously inspect the degree of deterioration of the weld line, and there is a disadvantage that maintenance is complicated and the inspection cost is increased.

In order to solve the disadvantages while making use of the advantages of the inner jacket type bath vessel, the present inventors have first made a method for producing a vinyl chloride polymer in an aqueous medium free from such problems. A partition plate is arranged side by side at right angles to the outer surface of the cylinder at an interval, and an outer strip is straddled between the ends of the partition plate, so that the heat partitioned by the partition plate between the inner cylinder and the outer strip is formed. A flow path wall having a flow path for the medium (hereinafter referred to as a “temperature control element”) is formed, and the temperature control element is fixed in the container body with the outer strip side facing the inner surface of the container body and at intervals. A tank container having a structure in which the upper and lower portions of the gap between the outer strip side of the temperature control element and the inner surface of the container body are sealed to form a gap chamber (hereinafter, referred to as a “temperature control element type tank container”);
The polymerization reaction is performed while maintaining the internal pressure of the gap chamber and the internal pressure of the space (hereinafter referred to as “main chamber”) surrounded by the inner surface of the container body and the inner cylinder of the temperature control element substantially equal to each other by a communication pipe or the like. A method was proposed.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a temperature control element type vessel in which the main chamber and the gap chamber are maintained at a substantially equal pressure by a communication pipe. It is an object of the present invention to provide a method capable of preventing a blockage of a communication pipe by a scale in performing a polymerization reaction, enabling safe and stable operation, and further improving productivity.

[0009]

That is, the gist of the present invention is as follows.
The polymerization of the vinyl chloride-based monomer in an aqueous medium is carried out by arranging partition plates at right angles to the outer surface of the inner cylinder at intervals, and straddling an outer strip between the ends of the partition plates, thereby forming the inner cylinder. A flow path wall (temperature control element) having a flow path of a heat medium partitioned by a partition plate is formed between the outer strip and the outer strip, and the temperature control element is provided inside the container body and the outer strip side is provided on the inner surface of the container body. A gap chamber formed by fixing the gap between the outer strip side of the temperature control element and the inner surface of the container body by sealing the upper and lower portions of the gap between the outer strip side of the temperature control element and the inner surface of the container body; And a main body chamber are communicated via a communication pipe, and when performed in a tank vessel provided with a reflux condenser in a gas phase portion, at least during the polymerization reaction, the communication pipe is connected to the main body chamber. Supplying liquid, characterized by polyvinyl chloride A method of manufacturing the body, consists in.

Hereinafter, the present invention will be described in detail. <Tank Vessel> Tank Vessel Main Body The temperature regulating element type vessel used in the method of the present invention has the following structure. That is, as shown in FIGS. 1 to 4, the partition plates 7 are juxtaposed at right angles to the outer surface of the inner cylinder 6 at intervals, and the outer strips 8 are straddled between the ends of the partition plates 7, whereby A temperature control element 5 having a heat medium flow path 9 partitioned by a partition plate 7 between the inner cylinder 6 and the outer strip 8 is formed, and the outer diameter of the temperature control element 5 is formed smaller than the inner diameter of the tank container. Then, the outer strip 8 side of the temperature control element is opposed to the inner surface of the container body 1 and fixed at intervals.

The temperature control element 5 is preferably fixed so that its center line substantially coincides with the center line of the container. At this time, the inner surface of the container body and the outer surface of the temperature control element (ie, the outer strip side) are used. A gap corresponding to the difference between the two diameters is formed between them, and this gap is substantially uniform in the circumferential direction. The lower end of the temperature control element may be directly fixed to the bottom end plate 3 around the tank nozzle 12 by continuous welding or the like as shown in FIG. 1 or the like, or may be fixed via a partition.

At the upper end of the temperature control element, a partition 13 is usually fixed to the cylindrical body 2 or the upper end plate 4 of the container. Since there is a space between the outer surface of the temperature control element 5 fixed inside the container body 1 and the inner surface of the container body 1 in this manner, the upper and lower portions of the gap are directly welded or by a partition 13 or the like. The structure is such that the gap chamber is formed by sealing. This can prevent the reaction mixture from penetrating into the above-mentioned gaps and the accompanying formation of scale adhesion.

It is preferable to provide an expansion and contraction absorbing portion for absorbing expansion and contraction of the temperature control element due to heat, for example, in a partition wall for sealing the upper and / or lower portion of the gap. It is necessary to have strength enough to withstand the temperature and pressure normally used in the polymerization of the system monomer. Further, in order to prevent the welding for sealing the upper and lower portions of the temperature control element and the gap between the temperature control element and the container main body and the partition from being broken by reaction pressure or the like, the inner surface of the container main body (usually,
For the sake of security, it is preferable to make the internal pressure of the space (main body chamber) surrounded by the top end plate and the bottom end plate) and the inner cylinder of the temperature control element substantially equal to the internal pressure of the gap chamber. In this case, the pressure resistance of the partition walls as described above is not required. In this case, the difference between the internal pressure of the main body chamber and the internal pressure of the gap chamber is 1
kg / cm ² or less, more preferably 0.7 kg / cm ²
It is preferable to make the following.

In the method of the present invention, a reflux condenser is installed in the gas phase of a temperature-regulating element type vessel, and the internal pressure of the gap chamber and the internal pressure of the main chamber are made equal using a communication pipe. To The connection part of the communication pipe on the tank container side may open directly to the gas phase part of the tank container as shown in FIG. 1 or open at the top of the reflux condenser as exemplified in FIGS. You may make it. As described below,
It is preferable to connect to the top of the reflux condenser because the effect of preventing scale adhesion to the reflux condenser can be obtained.

For the above reasons, it is important for the temperature control element type vessel having a reflux condenser to make the internal pressure of the main chamber substantially equal to the internal pressure of the gap chamber in order to maintain stable production. However, in the case of a polymerization reaction of a vinyl chloride-based monomer, a reaction mixture containing the vinyl chloride-based monomer intrudes into the communicating pipe, where the polymer is polymerized or scattered due to foaming or the like. Adheres to the inside (tubes, etc.) and the inner wall of the communication pipe, gradually grows scale, and eventually blocks the reflux condenser and the communication pipe, removing reaction heat and equalizing the pressure between the main chamber and the gap chamber. There is a risk that it will not be possible to secure them.

In the method of the present invention, the reaction mixture or polymer of the vinyl chloride monomer is attached to the reflux condenser or the communication pipe by supplying the liquid from the communication pipe to the main chamber, preferably via the reflux condenser. Instead, by washing into the tank container, scale generation / adhesion and blockage at these locations are prevented. The inlet of the liquid supplied in the method of the present invention can be provided, for example, near the opening of the communication pipe on the tank container side as shown in FIGS. ) Section, and a nozzle type supply port or a dispersion plate may be provided so that the entire inner surface of the vertical pipe is wetted.

Further, as shown in FIG.
A method provided below the gap chamber and supplying the liquid from the gap chamber to the main body chamber through the communication pipe is also a more preferable method for achieving the object of the present invention. Further, it is more preferable to supply the liquid from the communication pipe via a reflux cooler. When supplying the liquid via the reflux condenser, the reflux condenser is installed vertically, and the opening of the communication tube on the tank container side is provided at the top of the reflux condenser. Etc.) are more effective in preventing adhesion.

The liquid to be supplied is preferably water used as a medium for the polymerization reaction. Examples of the liquid include ion-exchanged water (deionized water), which does not adversely affect the quality of the obtained vinyl chloride polymer. If there is, it is not particularly limited. The supply of the liquid is preferably performed continuously or intermittently at least during the polymerization reaction.

The supply amount of the liquid is not particularly limited as long as it does not adversely affect the polymerization reaction and quality and there is no adverse effect such as overfilling. It is preferable that the total amount of the supplied liquid does not exceed the amount of volume reduction caused by polymerization of the vinyl chloride monomer. The supply of liquid is usually performed by a pump,
The type and the like are not particularly limited as long as it can be press-fitted into the pressurizing system, and a pump such as a spiral pump can be used. Further, the plunger pump is suitable because it can be press-fitted into a pressurizing system and has a quantitative property.

As shown in FIGS. 1 to 3, the flow path of the heat medium in the temperature control element 5 may be helical, the bottom end plate is helical, and the body of the container is meandering in the circumferential direction. The shape may be, and is not particularly limited. As a heat medium flowing in the flow path,
For heating, steam, hot water or the like is used.For cooling, room temperature water such as industrial water, water cooled by a separate refrigerator, a refrigerant such as ethylene glycol, a low-boiling refrigerant such as Freon, or the like can be used. Are not particularly limited.

The plate thickness of the inner cylinder 6 depends on the required strength and the interval between the partition plates 7, but since the interval between the partition plates 7 is smaller than the body length of the container body 1, the thickness of the inner cylinder 6 is small. The plate thickness can be reduced. The material of the inner cylinder 6 is, as described above, in consideration of the corrosion resistance of the portion in contact with the reaction mixture of the vinyl chloride monomer,
Stainless steel (solid stainless steel, stainless steel / carbon steel clad, especially SUS304 or SUS316L is preferable), glass lining, etc. are used, but any material that has corrosion resistance and resistance to stress corrosion cracking due to chlorine ions. However, there is no particular limitation.

From the viewpoint of preventing scale adhesion, the surface of the inner cylinder 6 is preferably smooth. As a method for smoothing the surface, a method such as buffing or electrolytic polishing which is usually carried out industrially is used. And is not particularly limited. In addition, the surface roughness is usually 10 μm or less, preferably 3 μm or less, more preferably 1 μm or less in Rmax. The measurement of Rmax may use the method specified in JIS B0601.

The tank container ancillary facilities present invention form, material, etc. of the reflux condenser used in the process is not limited in particular, a multi-tube heat exchanger or the like for the stainless steel and the material of the wetted portion, generally What is used for polymerization of a vinyl chloride monomer may be used.
The heat transfer area of the reflux condenser may be determined according to the required quality of the product type, the degree of heat removal load, the load control method, and the like. The method of load control may be a commonly used method, such as a method of controlling the amount of cooling water passing through a reflux condenser or the temperature of cooling water. In addition, this reflux cooler is installed in the gas phase portion of the vessel, but as described above, it is preferable that the reflux condenser is installed vertically on the upper mirror section of the vessel to prevent the scattered polymer particles from being retained or fixed. Is preferred. Other tank containers (hereinafter sometimes referred to as “polymerization tank”) The shape of the accompanying equipment such as the stirring blade and the baffle is not particularly limited.
Equipment and equipment generally used in conventional polymerization of vinyl chloride monomers can be used.

<Polymerization recipe> The polymerization method of the vinyl chloride monomer in an aqueous medium generally includes a suspension polymerization method, an emulsion polymerization method and a fine suspension polymerization method. The suspension polymerization of the vinyl chloride monomer is usually carried out by polymerizing the vinyl chloride monomer in an aqueous medium containing a dispersant in the presence of an oil-soluble polymerization initiator. Emulsion polymerization of a vinyl chloride monomer is carried out in an aqueous medium in the presence of an emulsifier and a water-soluble polymerization initiator. It is carried out by homogenizing and polymerizing in an aqueous medium in the presence of an emulsifier and an oil-soluble polymerization initiator.

Monomer The vinyl chloride monomer used in the method of the present invention includes a vinyl chloride monomer alone and a mixture of a copolymerizable monomer mainly composed of the vinyl chloride monomer. As the other monomer that can be copolymerized with the vinyl chloride monomer, those generally used conventionally can be used and are not particularly limited. Examples of the other monomers include, for example, vinyl acetate, vinyl propionate, vinyl esters such as vinyl stearate, methyl vinyl ether, ethyl vinyl ether, octyl vinyl ether, lauryl vinyl ether, alkyl vinyl ethers such as cetyl vinyl ether, ethylene, Α-olefins such as propylene,
Monounsaturated acids such as acrylic acid and methacrylic acid; alkyl esters such as methyl esters and ethyl esters of these monounsaturated acids; diunsaturated acids such as maleic acid, fumaric acid and itaconic acid; Examples thereof include one or a mixture of two or more of alkyl esters such as methyl ester and ethyl ester of a diunsaturated acid, a vinylidene compound such as vinylidene chloride, and an unsaturated nitrile such as acrylonitrile. These other monomers are usually used in a proportion of 30% by weight or less, preferably 20% by weight or less with respect to the vinyl chloride monomer, but there is no particular limitation.

Dispersant The dispersant that can be used in the method of the present invention may be any of those conventionally used in suspension polymerization of vinyl chloride monomers and is not particularly limited. Examples of the dispersant include partially saponified polyvinyl acetate (so-called polyvinyl alcohol), cellulose derivatives such as hydroxypropylmethylcellulose, and water-soluble polymers such as gelatin. In addition, anionic surfactants such as sodium lauryl sulfate and nonionic surfactants such as sorbitan fatty acid esters and glycerin fatty acid esters may be used as the dispersing aid. These dispersants or dispersing agents can be used alone or in combination of two or more. In addition, the amount of these dispersants used is not particularly limited, the type, stirring strength, polymerization temperature,
Depending on the type and composition of the other monomers to be copolymerized with the vinyl chloride monomer, the particle size of the intended vinyl chloride polymer, etc., it is generally different from the total amount of the vinyl chloride monomer. 0.001-2% by weight, preferably 0.03-1
It is used in the range of weight%.

Emulsifier Examples of the emulsifier used in the emulsion polymerization method and the fine suspension polymerization method include higher alcohol sulfates (alkali metal salts and ammonium salts), alkylbenzene sulfonates (alkali metal salts and ammonium salts), and higher alcohol sulfates. Examples include fatty acid salts (alkali metal salts, ammonium salts), other anionic surfactants, nonionic surfactants, and / or cationic surfactants. One of these surfactants may be used, or two or more of them may be used in combination. The amount of the emulsifier used is usually in the range of 0.1 to 3% by weight (preferably 0.3 to 1% by weight) with respect to the vinyl chloride monomer, but is not particularly limited. Further, these emulsifiers can be additionally used for adjusting foaming properties and the like, and in this case, they may be added after the completion of the polymerization reaction.

Polymerization Initiator The polymerization initiator used in the method of the present invention may be any of those conventionally used in various polymerization methods for vinyl chloride monomers, and is not particularly limited. Examples of the polymerization initiator used in the suspension polymerization method include, for example, t-butyl peroxypivalate, t-butyl peroxy neodecanoate, t-hexyl peroxy pivalate, t-hexyl peroxy neodecanoate, α-c Perester compounds such as milperoxy neodecanoate, diacyl or dialkyl peroxide compounds such as dilauroyl peroxide, diisopropyl peroxydicarbonate, di-2
Percarbonate compounds such as -ethylhexyl peroxydicarbonate; and azo compounds such as azobis (2,4-dimethylvaleronitrile) and azobisisobutyronitrile. These polymerization initiators can be used alone or in combination of two or more. The amount of the polymerization initiator used varies depending on the type of the initiator, the polymerization temperature, the desired reaction time and the like, but is generally in the range of 0.01 to 1% by weight based on the total amount of the vinyl chloride monomer.

Examples of the polymerization initiator used in the emulsion polymerization method include water-soluble peroxides such as persulfate (sodium salt, potassium salt, ammonium salt) and hydrogen peroxide, and water-soluble peroxides thereof. And a water-soluble reducing agent (for example, sodium sulfite, sodium pyrosulfite, sodium bisulfite, ascorbic acid, sodium formaldehyde sulfoxylate, etc.).

The polymerization initiator used in the fine suspension polymerization method includes azobisisobutyronitrile, azobis (2,4-
Dimethylvaleronitrile), lauroyl peroxide,
Examples thereof include a monomer-soluble (oil-soluble) initiator such as t-butyl peroxypivalate, or a redox-based initiator comprising a combination of these oil-soluble initiators and the above-described water-soluble reducing agents.

Other auxiliaries Further, in the method of the present invention, if necessary, a polymerization degree regulator (chain transfer agent, crosslinking agent), antioxidant, pH Various polymerization aids such as a regulator and a redox initiator activator can be appropriately added, and the amount of each of these components to be added is generally the same as that conventionally used in the polymerization of vinyl chloride monomers. Conditions are acceptable.

Examples of the polymerization degree modifier used for the polymerization of the vinyl chloride monomer include chain transfer agents such as trichloroethylene, carbon tetrachloride, 2-mercaptoethanol and octylmercaptan, diallyl phthalate and triallyl isocyanurate. And crosslinking agents such as ethylene glycol diacrylate and trimethylolpropane trimethacrylate.

<Polymerization method> Charge method In carrying out the method of the present invention, an aqueous medium, a vinyl chloride-based monomer, a polymerization initiator, a dispersant of a suspension polymerization method, an emulsion polymerization method And an emulsifier for fine suspension polymerization,
There are no particular restrictions on the proportion and method of charging the various polymerization aids. Polymerization temperature The polymerization temperature employed in the method of the present invention, the type of polymerization initiator used, the polymerization method, the presence or absence of a polymerization degree regulator,
Although it varies depending on the target degree of polymerization and the like, it is generally 0 to
A range of 90 ° C, especially 40-70 ° C, is often used.
In addition, during the reaction, even if the polymerization is carried out at a constant temperature,
Alternatively, the polymerization temperature may be changed during the polymerization.

Method of Terminating Polymerization In the method of the present invention, examples of a method of terminating the polymerization reaction include a method of adding a so-called polymerization inhibitor or a polymerization terminator, and a method of recovering an unreacted monomer from a polymerization tank. . <Post-treatment method> Operations such as dehydration and drying of the slurry of the vinyl chloride polymer produced by the suspension polymerization method may be dehydration and drying means such as centrifugal dehydration and fluidized drying, which are generally performed, and are particularly limited. Is not done. Operations such as drying of the latex of the vinyl chloride polymer produced by the emulsion polymerization method and the fine suspension polymerization method include conventional methods such as spray drying using a rotating disk or a spray nozzle such as a two-fluid nozzle. Means may be used, and there is no particular limitation. Before the drying treatment, a part of the moisture in the latex may be removed in advance, and a concentration operation may be performed to increase the concentration of the vinyl chloride polymer in the latex, or an operation of classifying and pulverizing the dried product may be performed. May go.

[0035]

EXAMPLES Next, specific embodiments of the method of the present invention will be described with reference to examples.
It is not limited by the following examples. <Example 1> An inner volume of 400 liters, a stirrer and a vertically arranged multi-tube reflux condenser with a heat transfer area of 1 m ^{2 in} the upper mirror were provided. A communication pipe as shown in FIG. 2 is installed in a stainless steel temperature control element type tank vessel divided into a gap chamber and a main body chamber by electropolishing to have a Rmax of about 1.2 μm. It was connected to the top, and the structure was such that water could be injected from the communication pipe via the reflux condenser.

In this tank, 100 k of vinyl chloride monomer was added.
g, 150 kg of deionized water, 60 g of partially saponified polyvinyl acetate as a dispersant, and 40 g of dioctyl peroxydicarbonate as an initiator, circulate warm water through the temperature control element and heat to 57 ° C. to initiate polymerization. did. From the start of the polymerization reaction (the polymerization reaction starts when the internal temperature of the polymerization tank reaches a predetermined reaction temperature) until the end of the recovery of unreacted vinyl chloride monomer, reflux cooling from the communication tube is performed. A total of 15 liters of deionized water was supplied at a flow rate of 2.5 liters / hr by a plunger pump into the tank container body via the vessel.

Polymerization was carried out while maintaining a reaction temperature of 57 ° C. until a predetermined polymerization rate was reached. Thereafter, the unreacted vinyl chloride monomer was recovered, the resulting slurry was extracted, ventilated, the vessel was opened, and the state of scale adhesion to the inner wall of the vessel was observed. After observing the scale adhesion state, the inner wall of the vessel was washed with low-pressure ion-exchanged water, and then the next batch test was repeated under the same conditions. Table 1 shows the observation results of the scale adhesion state.

[0038]

[Table 1]

<Example 2> An inner volume of 400 liters was provided with a stirrer and a vertically arranged multi-tube reflux condenser with a heat transfer area of 1 m ^{2 in} the upper mirror. The surface is adjusted to about Rmax 1.2 μm by electrolytic polishing, and a communicating pipe as shown in FIG. 3 is installed in a stainless steel temperature control element type tank container divided into a gap chamber and a main body chamber. It was connected to the top of the reflux condenser so that the inlet of water was the bottom of the gap chamber, and the structure was such that water could be injected from the gap chamber via the reflux condenser via the communication pipe.

In this tank, 100 k of vinyl chloride monomer was added.
g, 150 kg of deionized water, 60 g of partially saponified polyvinyl acetate as a dispersant, and 40 g of dioctyl peroxydicarbonate as an initiator, circulate warm water through the temperature control element and heat to 57 ° C. to initiate polymerization. did. From the start of the polymerization reaction (the polymerization reaction starts when the internal temperature of the polymerization tank reaches a predetermined reaction temperature) to the end of the recovery of unreacted vinyl chloride monomer, a communication pipe is provided from the gap chamber. Through a reflux condenser into the tank vessel body at a flow rate of 2.5 liters / hr by a plunger pump, with a total volume of 1
Five liters of deionized water was supplied.

Polymerization was carried out while maintaining a reaction temperature of 57 ° C. until a predetermined polymerization rate was reached. Thereafter, the unreacted vinyl chloride monomer was recovered, the resulting slurry was extracted, ventilated, the vessel was opened, and the state of scale adhesion to the inner wall of the vessel was observed. After observing the scale adhesion state, the inner wall of the vessel was washed with low-pressure ion-exchanged water, and then the next batch test was repeated under the same conditions. Table 2 shows the observation results of the scale adhesion state.

[0042]

[Table 2]

[0043]

According to the present invention, there is provided a temperature control element type vessel provided with a reflux condenser, wherein a gap is formed by sealing the upper and lower portions of the gap between the element and the vessel body. By using the method of the present invention in which the pressure equalization with the inside (main body chamber) is secured by the communication pipe and the vinyl chloride monomer is polymerized while supplying the liquid from the communication pipe into the main body chamber. Generation of scale in the communication pipe
High productivity can be achieved while preventing growth and preventing blockage of the communication pipe.

Further, by supplying this liquid to the main body chamber from the communication pipe via the reflux condenser, it is possible to prevent scale adhesion and blockage of the reflux condenser inside the reflux condenser,
Safer and more stable operation is possible.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a tank container used for carrying out the method of the present invention.

FIG. 2 is a longitudinal sectional view showing another example of a tank container used for carrying out the method of the present invention.

FIG. 3 is a longitudinal sectional view showing still another example of a tank container used for carrying out the method of the present invention.

FIG. 4 is an enlarged view of a main part of FIG. 1;

FIG. 5 is a longitudinal sectional view showing an example of a conventional tank container.

FIG. 6 is an enlarged longitudinal sectional view of a main part showing another example of a conventional tank container.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container main body 2 Cylindrical body 3 Bottom end plate 4 Top end plate 5 Temperature control element 6 Inner cylinder 7, 19 Partition plate 8 Outer strip 9, 21 Heat medium flow path 10 Heat medium flow path inlet 11 Heat medium flow path outlet 12 Tank Container nozzle 13 Partition wall 14 Gap chamber 15 Communication tube 16 Liquid inlet 17 Reflux cooler 18 (Outer) jacket 20 Inner strip H Gap

────────────────────────────────────────────────── ─── Continuation of front page (56) References Patent 2975832 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 2/00-2/30 B01J 19/00

Claims (7)

(57) [Claims] 1. The polymerization of vinyl chloride or a mixture of copolymerizable monomers mainly composed of vinyl chloride (hereinafter collectively referred to as “vinyl chloride-based monomer”) in an aqueous medium,
A partition plate is arranged side by side at a right angle to the outer surface of the inner cylinder at an interval, and an outer strip is straddled between the ends of the partition plate, so that heat separated by the partition plate between the inner cylinder and the outer strip is provided. A flow path wall having a flow path for the medium (hereinafter referred to as a “temperature control element”) is formed, and the temperature control element is fixed in the container body with the outer strip side facing the inner surface of the container body at intervals. A structure in which a gap is formed by sealing upper and lower portions of a gap between the outer strip side of the temperature control element and the inner surface of the container body, and the gap chamber, the inner surface of the container body, and the temperature control element. In a tank container in which a space surrounded by an inner cylinder (hereinafter referred to as “main body chamber”) is communicated through a communication pipe, and a reflux condenser is provided in a gas phase portion of the tank container. During the polymerization reaction, at least during the polymerization reaction, Method for producing a vinyl chloride polymer and supplying. 2. The method for producing a vinyl chloride polymer according to claim 1, wherein the supply of the liquid from the communication pipe to the main chamber is performed from the gap chamber through the communication pipe. 3. The method for producing a vinyl chloride polymer according to claim 1, wherein the supply of the liquid from the communication pipe to the main chamber is performed via a reflux condenser. 4. The production of a vinyl chloride polymer according to claim 3, wherein the reflux condenser is installed vertically, and an opening of the communication pipe on the main body chamber side is provided at the top of the reflux condenser. Method. 5. The process for producing a vinyl chloride polymer according to claim 1, wherein the liquid is continuously supplied during the polymerization reaction. 6. The liquid to be supplied is water.
The method for producing a vinyl chloride polymer according to any one of the above. 7. The vinyl chloride weight according to any one of claims 1 to 6, wherein the total amount of the supplied liquid is not more than an amount corresponding to a volume reduced by polymerization of the vinyl chloride monomer. Manufacturing method of coalescence.