JP3691747B2 - Polymerization apparatus and method for producing vinyl chloride polymer using the same - Google Patents

Description

【００４４】
【表２】

【００４５】
【発明の効果】
以上のように、本発明によれば、大型の重合容器を用いるにもかかわらず、重合容器内でのスケールの付着が起りにくく、冷却手段による除熱効率が良好で、高品質の重合体を効率良く製造することができる。得られる重合体は、嵩比重が大きく、粒度分布も狭く、これをシート化したものはフィッシュアイが少ないものである。
【図面の簡単な説明】
【図１】 本発明の重合装置を例示する概念図である。
【図２】 本発明に用いるパドル翼を例示する側面図である。
【図３】 実施例及び比較例におけるパドル翼の配置を示す概略図である。
【図４】 比較例におけるパドル翼の配置を示す概略図である。
【符号の説明】
１・・・重合容器
２・・・パドル翼
３・・・バッフル
４・・・ブレード
５・・・冷却ジャケット
６・・・還流コンデンサー
７・・・シャフト
８・・・駆動装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polymerization apparatus capable of producing a high-quality polymer efficiently, and a vinyl chloride using the same, in which scale adhesion in the polymerization container hardly occurs despite the use of a large polymerization container. The present invention relates to a method for producing a polymer.
[0002]
[Prior art]
Conventionally, as a polymerization apparatus for vinyl monomers, a polymerization apparatus having a polymerization vessel provided with a cooling means including a cooling jacket and a reflux condenser, a stirring device, a raw material charging nozzle, a polymer extraction nozzle, and the like. Are known. Such a polymerization apparatus is used in various polymerization methods such as suspension polymerization, emulsion polymerization, bulk polymerization, and solution polymerization, and mainly adopts a batch system.
[0003]
In the case of batch type, in order to improve productivity, the polymerization vessel should be made as large as possible, and the amount of vinyl monomer charged in one polymerization should be increased as much as possible. It is necessary to reduce the amount (DW) of deionized water to be charged.
[0004]
Considering heat removal by the jacket, it is effective to increase the length (L) of the straight body portion with respect to the inner diameter (D) as much as possible in order to increase the cooling area. However, when L becomes too long, the upstream and downstream in the polymerization vessel and the mixing thereof become worse, the particle size distribution of the resulting polymer becomes wider, and the fish eye increases when the polymer is made into a sheet. Although it is possible to increase the number of stages of the stirring blades, there is a limit when considering uniform mixing in the upper and lower portions in the polymerization vessel. This becomes more remarkable when the ratio (M / DW) of the amount of vinyl monomer (M) and the amount of deionized water (DW) is increased.
[0005]
On the other hand, if the number of stages of the stirring blades is reduced to one or two, the interval between the stirring blades is increased, a poorly flowing portion is formed between the stirring blades and the stirring blade, and the particle size distribution is widened. Further, when the M / DW ratio was large, this influence was particularly great, and grains could not be formed, or the polymer became block-like.
[0006]
In the polymerization, a so-called polymer scale is likely to adhere to the inner wall, baffle, stirring blade and the like of the polymerization vessel. Since this scale increases the heat transfer resistance of the polymerization vessel, there arises a problem that the heat removal capability of the cooling means is reduced or the quality of the obtained polymer is deteriorated due to contamination of the scale. Therefore, the scale adhering to the inner wall of the polymerization vessel needs to be periodically removed by solvent cleaning, a high-pressure jetter or the like.
[0007]
Solvent cleaning and high-pressure jetter cannot sufficiently remove the scale. Although a scale adhesion inhibitor has been developed, it is difficult to apply a scale adhesion inhibitor uniformly on the inner wall, baffle, stirring blade, etc. of a polymerization vessel in a large polymerization apparatus. Scale adhesion prevention effect cannot be expected. In particular, in a large polymerization apparatus equipped with a reflux condenser, there is a disadvantage that scale adhesion at the gas-liquid interface of the polymerization vessel becomes remarkable because mixing of the refluxed condensate becomes insufficient.
[0008]
[Problems to be solved by the invention]
The object of the present invention is to produce a high-quality polymer efficiently by using a large-sized polymerization vessel, in which scale adhesion is difficult to occur in the polymerization vessel, heat removal efficiency by the cooling means is good. Another object of the present invention is to provide a polymerization apparatus that can be used, and a method for producing a vinyl chloride polymer using the polymerization apparatus.
[0009]
[Means for Solving the Problems]
That is, the present invention achieves the above-mentioned problem. First, a polymerization vessel composed of a substantially cylindrical straight body part, a lid part and a bottom part for closing the upper and lower sides thereof, and a center line of the straight body part as an axis. And a polymerization apparatus equipped with a paddle blade that rotates in the polymerization vessel and a baffle that blocks the stirring flow of the contents by the paddle blade,
The polymerization container has an internal volume of 100 m ³ or more, a ratio (L / D) of the length (L) of the straight body part to the inner diameter (D) of 1.5 to 2.5,
The paddle blades are arranged in three to four stages along the center line of the straight body part, and the uppermost paddle blades have the center line of the blade vertical width lower than the upper end position of the straight body part of the polymerization vessel. In the direction of 0.35L (where L is as defined above), the lowermost paddle blade is positioned above the lower end position of the straight body portion in the centerline of the blade vertical width of the blade. The remaining paddle blades (1 to 2 stages) are arranged so that the distance between the center line of the uppermost blade and the center line of the lowermost blade is (n−). 1) Arranged so that the center line of the blade vertical width of the blade comes within a range of ± 0.25 D / n in the vertical direction from the equally divided position (where n is the total number of stages of the paddle blade),
Further, a long baffle is arranged in the vertical direction along the inner wall of the polymerization vessel, and the length (P) of the baffle is expressed by the following formula:
0.85L ≦ P ≦ L (wherein L is as defined above)
And the polymerization apparatus is arranged such that the upper end of the baffle is located within a range of 0.25D from the position of 0.1D upward from the position of the upper end of the straight barrel portion of the polymerization vessel. .
[0010]
Secondly, the present invention provides a method for producing a vinyl chloride polymer, wherein the polymerization apparatus described above is used to polymerize a vinyl chloride monomer or a mixture of vinyl monomers mainly composed thereof.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
(Polymerization equipment)
For example, as shown in FIG. 1, the polymerization apparatus of the present invention has a polymerization vessel 1 composed of a substantially cylindrical straight body portion, a lid portion and a bottom portion for closing the upper and lower sides thereof, and a center line A of the straight body portion. And a baffle 3 disposed in the vertical direction along the inner wall of the polymerization vessel.
[0012]
Polymerization vessel 1 used in the present invention, internal volume of 100 m ³ or more, preferably, large containers of 100 to 250 m ^3. Further, the ratio (L / D) of the length (L) of the straight body portion to the inner diameter (D) of the polymerization vessel 1 is 1.5 to 2.5, preferably 1.7 to 2.0. . When this ratio is less than 1.5, since the cooling area with respect to the volume of the polymerization vessel is small, it cannot be efficiently cooled. If this ratio is too large, mixing failure may occur between the upper and lower sides in the polymerization vessel.
[0013]
As shown in FIG. 2, the paddle blade used in the present invention is a stirring blade provided with a plurality of plate-like, substantially rectangular blades 4 centered on the rotation axis B in a radial pattern. The number of blades 4 is usually 2 to 6, preferably 2.
The size of the blade 4 is not particularly limited as long as it does not affect the rotation, but preferably satisfies the following relational expression.
0.35 ≦ d / D ≦ 0.55 and 0.10 ≦ n · w / D ≦ 0.16
(Wherein, D is as defined above, d is the blade diameter of the paddle blade, w is the vertical width of the blade 4, and n is the number of stages of the paddle blade), as shown in FIG.
In the polymerization apparatus of the present invention, such paddle blades 2 are arranged in three to four stages along the center line A of the straight body portion of the polymerization container as shown in FIG.
[0014]
The height of the center line C (hereinafter referred to as the center line C) of the blade vertical width shown in FIG. 2 is the uppermost position TL (Tangential) of the straight barrel portion of the polymerization vessel 1 shown in FIG. Line)) in the range of 0.35L downward (where L is as defined above), the lowest paddle blade has a height of the centerline C of the blade from the lower end position TL of the straight body portion. Arranged to be within 0.25D range upwards;
The remaining paddle blades (one to two stages) located between the uppermost blade and the lowermost blade have a distance (n−1) between the centerline C of the uppermost blade and the centerline C of the lowermost blade. ) From the equally divided position, it is arranged so that the center line C of the wing comes within ± 0.25 · D / n in the vertical direction along the center line A of the straight body part.
[0015]
The paddle blade 2 is installed at such an attachment position via a shaft 7 provided on the center line A of the straight body portion, and the shaft 7 is connected to a driving device 8 such as a stirring motor for applying a rotational force thereto. . The driving force of the driving device is preferably 7.8 × 10 ^{2 to} 1.7 × 10 ³ W (80 to 170 kg · m / s) per weight (t) of the contents of the polymerization vessel. Note that the installation position of the driving device may be either the upper part or the lower part of the polymerization vessel 1.
[0016]
As shown in FIG. 1, the baffle 3 used in the present invention is arranged in the vertical direction along the inner wall of the polymerization vessel. There is no restriction | limiting in particular as a shape of the baffle 3, A well-known shape may be sufficient, For example, things, such as flat form and pipe shape, can be mentioned. The baffle length (P) is:
0.85L ≦ P ≦ L (wherein L is as defined above)
It is a length that satisfies When the length (P) is out of this range, mixing of the charged contents becomes non-uniform, so that the particle size distribution of the obtained vinyl chloride polymer becomes wide, the bulk specific gravity decreases, As a result, the polymer scale is likely to adhere to the inside of the polymerization vessel.
[0017]
The baffle 3 is installed such that the upper end of the baffle 3 is within the range of 0.25D downward from the position 0.1D upward from the straight barrel upper end position TL of the polymerization vessel. When the installation position of the baffle 3 is out of this range, the amount of scale adhesion near the gas-liquid interface in the polymerization vessel increases.
The number of baffles 3 is not particularly limited, but is preferably 1-8.
Further, as in JP-A-7-233202, a meandering pipe through which a refrigerant is passed between two baffles that are adjacent to each other may be installed.
[0018]
The polymerization apparatus of the present invention preferably has a cooling means. The cooling means is not particularly limited as long as it can cool the contents of the polymerization vessel, and known cooling means can be used. For example, as shown in FIG. 1, it is provided on the outer peripheral surface of the polymerization vessel. , A cooling jacket 5 that conducts a coolant such as cooling water, a reflux condenser 6 that is provided at the top of the polymerization vessel, condenses the monomer vapor generated in the polymerization vessel, and recirculates it to the polymerization vessel. Can do. The reflux condenser 6 used in the present invention preferably has a heat removal amount by the reflux condenser 6 of 5% or more of the total polymerization heat generation amount.
As materials for the inner surface of the polymerization vessel, baffle, paddle blade, shaft, etc. used in the polymerization apparatus of the present invention, stainless steels such as high chromium high purity ferritic stainless steel, duplex stainless steel, austenitic stainless steel and the like are preferable.
[0019]
(Polymerization method)
The method for producing a vinyl chloride polymer of the present invention uses the polymerization apparatus.
As a monomer used in the production method of the present invention, a mixture of vinyl chloride and other vinyl monomers mainly composed of vinyl chloride and copolymerizable therewith (vinyl chloride is 50% by weight). Can be used.
[0020]
Examples of vinyl monomers (comonomer) to be copolymerized with vinyl chloride include vinyl esters such as vinyl acetate and vinyl propionate; acrylic acid such as acrylic acid, methyl acrylate and ethyl acrylate, or esters thereof; methacrylic acid, Methacrylic acid or its ester such as methyl methacrylate; Olefin such as ethylene or propylene; Maleic anhydride; Acrylonitrile; Styrene; Vinylidene chloride; Other monomers copolymerizable with vinyl chloride, which may be used alone or Two or more kinds can be used in combination.
[0021]
The method for polymerizing the monomer is not particularly limited, but when using the polymerization apparatus of the present invention, the polymerization method is preferably a polymerization method in an aqueous medium such as suspension polymerization or emulsion polymerization. In polymerization, a stable dispersant and a polymerization initiator used for polymerizing a vinyl chloride polymer in an aqueous medium can be added in a normal amount.
[0022]
Examples of the stable dispersant include water-soluble cellulose ethers such as methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and hydroxypropylmethylcellulose; water-soluble partially saponified polyvinyl alcohol; oil-soluble partially saponified polyvinyl alcohol; acrylic acid polymer; Oil-soluble emulsifier such as sorbitan monolaurate, sorbitan trioleate, glycerin tristearate, ethylene oxide propylene oxide block copolymer; water-soluble emulsifier of polyoxyethylene sorbitan monolaurate, polyoxyethylene glycerin oleate, sodium laurate These can be used alone or in combination of two or more.
The addition amount of these stable dispersants is usually 0.01 to 5 parts by weight with respect to 100 parts by weight of the charged monomer.
[0023]
Examples of the polymerization initiator include percarbonate compounds such as diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, diethoxyethyl peroxydicarbonate; t-butylperoxypivalate, t-hexylperper Perester compounds such as oxypivalate, t-butylperoxyneodecanoate, α-cumylperoxyneodecanoate, t-butylperoxyneoheptanoate; acetylcyclohexylsulfonyl peroxide, 2,4,4 -Peroxides such as trimethylpentyl-2-peroxyphenoxyacetate, 3,5,5-trimethylhexanoyl peroxide; azobis-2,4-dimethylvaleronitrile, azobis (4-methoxy-2,4-dimethylvalero) Nitrile) etc. Azo compounds; further pressurized potassium sulfate, pressurized ammonium sulfate, can be mentioned hydrogen peroxide, which can be used alone or in combination of two or more.
[0024]
The addition amount of these polymerization initiators is usually 0.01 to 3 parts by weight with respect to 100 parts by weight of the charged monomer. Moreover, you may add a chain transfer agent (For example, common things, such as 2-mercaptoethanol) as needed.
[0025]
In addition, when using the polymerization apparatus of the present invention, monomers such as an inner wall of a polymerization vessel, a stirring shaft, a paddle blade, a baffle, a condenser, a header, a search coil, a bolt, a nut, etc. It is preferable to form a scale adhesion preventing coating film by applying a scale adhesion preventing agent to other parts that come into contact and then drying it.
[0026]
The scale adhesion preventing agent may be a known one, for example, a self-condensation product of polyhydric phenols and polyhydric naphthols (Japanese Patent Laid-Open No. 54-7487); a condensate of 1-naphthol and formaldehyde (special Kaisho 57-164107); condensates of phenolic compound toaldehydes (Japanese Patent Laid-Open No. 54-36389); mixed solutions of quinone-amine compounds and organic silica sol (Japanese Patent Laid-Open No. 1-135802); naphthol Sulfide compounds (Japanese Patent Laid-Open No. 4-311702); mixtures and / or reaction products of electron-donating dyes and aryl sulfonic acids (Japanese Patent Laid-Open No. 5-70505); phenothiazine derivatives (Japanese Patent Laid-Open No. 5-501892) A quinone compound and / or a reduced product thereof (JP-A-5-279404); a reaction product of a ketone resin and a phenolic compound (JP-A 62-236804); a dye, a pigment, a conjugated π 5 or more bonds Aromatic compounds having 5 or more conjugated π bonds (USP-4,757,124); polyaromatic amines (USP-4,024,330); salts of cationic compounds and anionic compounds (GB-2,170,604); A reaction product with aminobenzoic acid (EP-0498142A1); an initial condensation modified product of phenols and aldehydes (Japanese Patent Laid-Open No. 3-501884), and the like.
[0027]
The method of applying the coating liquid to the inner wall surface of the polymerization vessel is not particularly limited. For example, brush coating, spray coating, filling the polymerization vessel with a polymer scale anti-adhesive agent, and other methods such as drawing out, etc. An automatic coating method described in JP-A-57-61001, JP-A-55-36288, JP-B-56-501116, JP-A-56-501117, JP-A-59-11303, or the like may be used. it can.
[0028]
The method of drying the wet surface after applying the coating liquid is not limited, and for example, the following method can be used. That is, after applying the polymer scale adhesion inhibitor, a method of applying warm air heated appropriately to the application surface, or the inner wall surface of the polymerizer and other surfaces to which the polymer scale adhesion inhibitor should be applied, for example, A method of heating to 30 to 80 ° C. and directly applying a polymer scale adhesion preventing agent to the heated surface can be used. And after drying an application surface, the application surface is washed with water as needed.
[0029]
The coating film thus obtained has a total coating amount after drying of usually 0.001 to 5 g / m ² , particularly preferably 0.05 to ² g / m ² .
[0030]
As the aqueous medium used for the polymerization of the vinyl chloride monomer, deionized water is usually used. Furthermore, in this polymerization system, if necessary, a polymerization regulator, a chain transfer agent, a pH regulator, a gelation improver, an antistatic agent, a crosslinking agent, which are appropriately used for the polymerization of the vinyl chloride monomer, Stabilizers, fillers, antioxidants, buffering agents and the like can also be added.
[0031]
Other conditions for this polymerization, aqueous medium to the polymerization vessel, vinyl chloride monomer, in some cases other comonomer, suspending agent, polymerization initiator, etc. may be charged in the same manner as before, The conditions such as the charging ratio may be the same, and the polymerization temperature may be in the range of 20 to 80 ° C. of the normal polymerization temperature of vinyl chloride.
[0032]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. The present invention is not limited to these examples. Various conditions and experimental results in the examples are shown in Table 1.
[0033]
(Example 1)
As shown in FIG. 1, a polymerization apparatus including a polymerization vessel 1, a paddle blade 2, a baffle 3, a cooling jacket 5, a reflux condenser 6, and a driving device 8 was configured. The internal volume of the polymerization vessel was 130 m ³ , the inner diameter (D) was 4,200 mm, and the length of the straight body portion (L) was 7,900 mm [L / D = 1.88].
The paddle blade 2 includes two blades 4 as shown in FIG. 2, and is installed in three stages as shown in the schematic layout of the paddle blades in FIG. 3A. The uppermost paddle blade is the center of the blade. Line C is 2200 mm below the upper end position TL of the straight body part, the lowermost paddle blades have the center line C of the blades aligned with the lower end position TL of the straight body part, and the middle paddle blades are the lower paddle blades. It was arranged 3000 mm above the wing centerline C. The baffle 3 was a flat plate having a length of 7200 mm, and was arranged so that the upper end of the baffle 3 was 450 mm below the upper end position TL of the straight body portion.
[0034]
The polymerization vessel 1 of such a polymerization apparatus was charged with 54,900 kg of ion exchange water, 13.8 kg of partially saponified polyvinyl alcohol, and 9.2 kg of hydroxypropyl methylcellulose. Next, after evacuating to an internal pressure of 7.98 kPa (gauge pressure) with a vacuum pump, 47,700 kg of vinyl chloride monomer was charged, and while stirring with the paddle blade 2, di-2-ethylhexyl par was used as a polymerization initiator. 25.3 kg of oxydicarbonate was injected into the polymerization vessel. The stirring power by the driving device 8 at the start of the polymerization was 1.3 × 10 ³ W (130 kg · m / sec) per weight (t) of the contents of the polymerization vessel.
[0035]
Then, hot water is passed through the cooling jacket 2 to carry out the polymerization reaction while maintaining the polymerization temperature at 53 ° C., and when the internal pressure of the polymerization vessel reaches 588 kPa (gauge pressure), the polymerization is stopped and unreacted monomers are removed. The polymer was recovered and the resulting polymer was extracted out of the vessel in the form of a slurry. The state of scale adhesion inside the vessel was observed, the polymer was dehydrated and dried, and subjected to the test by the following method.
・ Polymerization scale adhesion status:
Evaluation was performed according to the following criteria.
A: Almost no scale adhered.
B: Scale adhered to the entire circumference of the polymerization vessel near the gas-liquid interface.
C: Scale adhered to the top of the baffle and the polymerization vessel near the gas-liquid interface.
D: Scale adhered to the straight body of the polymerization vessel and the back side of the baffle.
・ Measurement of bulk specific gravity:
The obtained polymer was measured according to JIS K-6721.
・ Measurement of particle size distribution:
The obtained polymer was sieved using # 60, # 100, and # 200 sieves according to JIS Z-8801, and the passing amount was measured and expressed in weight%.
・ Fisheye measurement:
100 parts by weight of obtained polymer, 50 parts by weight of DOP, 0.1 part by weight of barium stearate, 0.1 part by weight of cadmium stearate, 0.8 part by weight of cetanol, 2.0 parts by weight of tin stabilizer, 0.5 part by weight of titanium dioxide and 0.1 part by weight of carbon black The portion was mixed and kneaded for 5 minutes with a 6 inch roll at 140 ° C., separated as a sheet having a thickness of 0.3 mm, and indicated by the number of white transparent particles in 100 cm ^{2 of} this sheet.
[0036]
(Example 2)
The position of the paddle blade 2 is shown in FIG. 3B. As for the uppermost paddle blade, the center line C of the blade is 1800 mm below the upper end position TL of the straight body portion, and the lowermost paddle blade is The center line C was set to 500 mm above the lower end position TL of the straight body part, and the middle paddle blade was polymerized in the same manner as in Example 1 except that it was placed 2900 mm above the center line C of the lowermost paddle blade.
[0037]
(Comparative Example 1)
As shown in FIG. 3 (c), the mounting position of the uppermost paddle blade is arranged so that the center line C of the blade is 3500 mm below the upper end position TL of the straight body portion (outside the range of 0.35L). Then, polymerization was performed in the same manner as in Example 1 except that the attachment position of the lower blade was matched with the lower end position TL of the straight body portion, and the middle paddle blade was arranged at the center of the uppermost and lowermost stages.
[0038]
(Comparative Example 2)
As shown in FIG. 4D, the mounting position of the uppermost paddle blade is arranged so that the center line C of the blade is 2200 mm below the upper end position TL of the straight body portion (within a range of 0.35 L). Then, polymerization was carried out in the same manner as in Example 1 except that the attachment position of the lower blade was matched with the lower end position TL of the straight body portion, and the middle paddle blade was placed 3300 mm above the lower blade.
[0039]
(Comparative Example 3)
As shown in FIG. 4 (e), the number of paddle blades is five, and the attachment position of the uppermost paddle blades is 1800 mm below the upper end position TL of the straight body (0.35L). And the lower blade position is aligned with the lower end position TL of the straight body portion, and the three-stage stirring blades between the uppermost and lowermost stages are evenly spaced, that is, 1525 mm apart. Polymerization was carried out in the same manner as in Example 1 except that the polymerization was performed.
[0040]
(Comparative Example 4)
As shown in FIG. 4 (f), the number of paddle blades is set to two, and the attachment position of the uppermost paddle blade is set such that the center line C of the blade is 2500 mm below the upper end position TL of the straight body portion (0.35L). The polymerization was carried out in the same manner as in Example 1 except that the lowermost blade was mounted 1000 mm above the lower end position TL of the straight body portion.
[0041]
(Comparative Example 5)
The polymerization reaction was carried out using the same polymerization apparatus as in Example 1 except that the upper end of the baffle 3 was placed 250 mm above the upper end position TL of the straight barrel part (outside the range of TL + 200 mm). While observing the state of scale adhesion, the polymer was subjected to the test by the above method.
[0042]
(Comparative Example 6)
Except that the length (P) of the baffle 3 was 6000 mm (outside the range of 0.85 L ≦ P ≦ L), the polymerization reaction was performed using the same polymerization apparatus as in Example 1, and the scale adhesion in the vessel And the polymer was subjected to the test by the above method.
The test results of Examples 1 and 2 are shown in Table 1, and the test results of Comparative Examples 1 to 6 are shown in Table 2.
[0043]
[Table 1]

[0044]
[Table 2]

[0045]
【The invention's effect】
As described above, according to the present invention, despite the use of a large polymerization vessel, the scale does not easily adhere to the polymerization vessel, the heat removal efficiency by the cooling means is good, and a high-quality polymer is efficiently produced. Can be manufactured well. The obtained polymer has a large bulk specific gravity and a narrow particle size distribution, and a product obtained by forming this into a sheet has few fish eyes.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram illustrating a polymerization apparatus of the present invention.
FIG. 2 is a side view illustrating a paddle blade used in the present invention.
FIG. 3 is a schematic view showing the arrangement of paddle blades in an example and a comparative example.
FIG. 4 is a schematic view showing the arrangement of paddle blades in a comparative example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Polymerization container 2 ... Paddle blade 3 ... Baffle 4 ... Blade 5 ... Cooling jacket 6 ... Reflux condenser 7 ... Shaft 8 ... Drive device

Claims (2)

A polymerization vessel comprising a substantially cylindrical straight body portion, a lid portion and a bottom portion for closing the upper and lower sides thereof, a paddle blade rotating around the center line of the straight body portion, and stirring the inside of the polymerization vessel, and the paddle blade In a polymerization apparatus equipped with a baffle that disturbs the stirring flow of the contents by
The polymerization container has an internal volume of 100 m ³ or more, a ratio (L / D) of the length (L) of the straight body part to the inner diameter (D) of 1.5 to 2.5,
The paddle blades are arranged in three to four stages along the center line of the straight body part, and the uppermost paddle blades have the center line of the blade vertical width lower than the upper end position of the straight body part of the polymerization vessel. Is located within the range of 0.35 L in the direction (where L is as defined above), and the lowermost paddle wing is positioned above the lower end position of the straight body portion. The remaining paddle blades (one to two stages) are arranged so that the distance between the center line of the uppermost blade and the center line of the lowermost blade is (n−). 1) Arranged so that the center line of the blade vertical width of the blade comes within a range of ± 0.25 D / n in the vertical direction from the equally divided position (where n is the total number of stages of the paddle blade),
Further, a long baffle is arranged in the vertical direction along the inner wall of the polymerization vessel, and the length (P) of the baffle is represented by the following formula:
0.85L ≦ P ≦ L (wherein L is as defined above)
And the upper end of the baffle is arranged such that the upper end position of the baffle is within the range of 0.25D from the position of 0.1D upward from the position of 0.1D upward. A method for producing a vinyl chloride polymer, wherein the polymerization apparatus according to claim 1 is used to polymerize vinyl chloride or a mixture of vinyl monomers mainly composed of vinyl chloride.

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