JPH01275611A - Manufacture of vinyl chloride polymer - Google Patents

Abstract

PURPOSE:To prevent scale from adhering to parts of a polymerizer in contact with a monomer, by applying a specific reaction product on the parts of the polymerizer before vinyl chloride monomer is polymerized. CONSTITUTION:Vinyl chloride monomer or a mixture of vinyl chloride monomer with a monomer copolymerizable therewith is polymerized in an aqueous medium or in bulk as follows. A cyclopentadiene monomer or a cyclopentadiene polymer in the form of an oil or a wax is reacted with a phenol compound and an aromatic amine compound. The obtained reaction product is applied on the inner wall of a polymerizer and other parts in contact with the monomer. The above cyclopentadiene polymer in the form of an oil or a wax can be produced by thermal polymerization or cationic polymerization of a cyclopentadiene monomer or a mixture thereof with a monomer copolymerizable therewith.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for producing vinyl chloride polymers, and more specifically, to prevent scale from adhering to the inner wall of a polymerization vessel and other parts that come into contact with monomers. The present invention relates to a method for producing a vinyl chloride polymer for preventing.

(Prior art) Conventionally, when polymerizing vinyl chloride-based heavy bodies in an aqueous medium or in bulk, a chemical was applied to the internal surface of the polymerization vessel in order to prevent scale from adhering to the interior walls of the polymerization vessel. Various methods have been proposed. As a coating agent, for example, a reaction product of a cyclopentadiene polymer and a phenol compound (Japanese Patent Publication No. 60-59247), a reaction product of a cyclopentadiene monomer and a heptanoyl compound (Japanese Patent Publication No. 60-59247), -71614), linear or branched polyaromatic amines (Japanese Patent Publication No. 60-54525), but even when these coating agents are used, the
If batch polymerization is repeated, scale will adhere to the inner walls of the polymerization vessel, which may reduce the heat removal capacity of the polymerization vessel, and the scale peeled off during polymerization may get mixed into the product, causing fish eye. There were problems such as deterioration of product quality. In addition, coating agents made of linear or branched polyaromatic amines not only have insufficient long-lasting effect in preventing scale adhesion, but also contain only a few of these per monomer such as vinyl chloride in the polymerization system. Even if only ppm remains, there are disadvantages such as slow polymerization rate and increase in fish eyes.

On the other hand, in recent years, as a method for producing vinyl chloride polymers that uses a reflux condenser to remove the heat of polymerization reaction has been adopted on an industrial scale, it has become possible to improve the ability to prevent scale from adhering to condensers. There is a strong need for the development of a coating agent. In other words, condensers have complex structures such as heat transfer tubes, and if scale adheres to them, it takes a great deal of effort and time to remove them. It wasn't enough. Furthermore, since the heat transfer area of the capacitor is large, not only does the amount of coating agent required for coating increase, but it is also virtually impossible to completely remove the coating agent from inside the capacitor by washing with water, so polymerization It is considered an extremely important technical challenge to develop a coating agent that does not deteriorate the quality of the product even if it remains in the coating, and has a long-lasting effect on preventing scale.

(Problems to be Solved by the Invention) The object of the present invention is to provide an FC coating agent that does not cause deterioration in quality such as coarsening of polymer particles and increase in fissure eye, and has an excellent long-lasting effect of preventing scale. Another object of the present invention is to provide a method for producing a vinyl chloride polymer that has improved ability to prevent scale from adhering to the inner walls of a polymerization vessel, flux, condenser, etc.

(Means for Solving the Problems) This object of the present invention is to prepare a mixture of a vinyl chloride monomer or a monomer copolymerizable with vinyl chloride and a vinyl chloride monomer in an aqueous medium or in a lump. When polymerizing, a cyclopentadiene compound, that is, a cyclopentadiene monomer or an oily or waxy cyclopentadiene polymer (A), a phenol compound (B)
This is accomplished by applying in advance a reaction product obtained by reacting the aromatic amine compound (C) to the inner wall of the polymerization vessel and other parts that come into contact with the monomers.

The present invention will be explained in detail below.

The cyclopentadiene monomer used as a raw material for the coating agent for preventing scale adhesion in the present invention includes cyclopentadiene, lower alkyl-substituted cyclopentadiene such as methyl-substituted and ethyl-substituted cyclopentadiene, and dimers thereof;
Dimers, codimers, and cyclopentadiene and the above-mentioned lower alkyl-substituted cyclopentadiene and monoolefins such as ethylene, propylene, butene, pentene, styrene, α-methylstyrene, 1,3-butadiene, isoprene, 1. Conjugated dienes such as 3-pentadiene, vinyl acetate, vinyl propionate, acrylic esters,
It is selected from methacrylic acid esters, acrylonitrile, acrolein, Diels-Alder adducts with vinyl monomers having polar groups such as allyl alcohol, and the like.

In addition, oily or waxy cyclopentadiene polymers are mixed with cyclopentadiene monomers or comonomers thereof in the presence or absence of an inert solvent such as benzene, toluene, xylene, etc. It can be obtained by a known method such as thermal polymerization of a mixture of (for example, JP-A-55-98383) or cationic polymerization.

The above comonomers include monoolefins such as ethylene, propylene, butene, pentene, styrene, and α-methylstyrene, conjugated dienes such as 1.3-butadiene, isoprene, and 1.3-pentadiene, vinyl acetate, and vinyl propionate. , acrylic esters, methacrylic esters, acrylonitrile, acrolein, vinyl monomers having polar groups such as allyl alcohol, and phenols such as phenol, cresol, and oxystyrene. Oily polymers usually have a viscosity of 5° to s at 25°C.
o, ooo centiboise, preferably 50o-3Q, 0
The waxy polymer has a melting point of 140°C or lower, preferably 100°C or lower. If a resinous polymer is used instead of this polymer, the adhesion between the coating film and the inner wall surface of the polymerization vessel when used as a coating agent is poor, resulting in a decrease in the sustained effect of preventing scale.

A typical example of the phenol compound used as a raw material for the coating agent in the present invention is a compound represented by the following structural formula (I).

In the above formula, R1 is -H, -0f(, -CHO, -CO
Oh.

-No.2. -CH)OH, -C(CH3)2 +OH
.

It represents halogen or an alkyl group having 1 to 9 carbon atoms, and R2 represents -H, --OH, halogen or an alkyl group having 1 to 9 carbon atoms.

Such compounds include phenol, catechol,
Resorcinol, Hydroquinone, Pyrogallol, Hydroxyhydroquinone, Phloroglycitur% (0+
ml p-) hydroxybenzaldehyde, salicylic acid, 4-hydroxybenzoic acid, 3.4-dihydroxybenzoic acid, (O, ml T)-) nitrophenol, 4.4
'-dihydroxyphenylmethane, 2,2-bis(4-
hydroxyphenyl) furopane (also known as bisphenol A)
), (Oemsp-)chlorophenol, (Os me
Examples include p-)bromophenol, (On mm p-)cresol, pt-butylphenol, and 4-t-butylcatechol.

When polyhydric phenol is used, the scale adhesion prevention effect is particularly remarkable, but this is because the polymerization inhibition effect or the hydrophilic effect of the coating formed on the internal surface of the polymerization vessel differs depending on the number of hydroxyl groups. This is thought to be due to the fact that

Further, a typical example of the aromatic amine compound used as a raw material for the coating agent in the present invention has the following structural formula (n
) or (1).

Structural formula (■): Structural formula (■): In the above structural formula (II), R, d-Hl-NH2
, -NHR,', -NF11'R2' -CHol-C
'OOH, -NO2, -0H1-8H, halogen, represents an alkyl group or alkoxy group having 1 to 5 carbon atoms, R4 and R, -)I, -NH2, -NHR
I', -NR1'R2' -OH.

It represents a halogen or an alkyl group having 1 to 5 carbon atoms. Further, RII and R2' represent an alkyl group having 1 to 5 carbon atoms.

Such compounds include aniline, (0°m, p-
) phenylenediamine, (0-mop) aminobenzaldehyde, co, m, p-) aminobenzoic acid, (o
+"ep) nitroaniline, (Oemsp->aminophenol, (o, m, p-)) luidine, 2-aminobenzenethiol, ('+m*p-)l miloaniline, z4-diaminotoluene, 3.5- Cyamic mylobenzene, (Oemsp-)methoxyaniline, 4-methoxy-〇-7-enylenediamine, 4-ria-0-phenylenediamine, 2'-amino-4-chlorophenol, 1.3.5-) Liaminobenzene, N,N-dimethyl-p-phenylenediamine, 2-1fk-1,5-phenylenediamine, Mura-diaminobenzoic acid, 4-nitro-0-7enylenediamine, 2,4-diaminophenol, etc. is exemplified.

Furthermore, in the structural formula (Ill), Ls#1-NH
-1-N-N-1-〇-1-〇〇-1-C'0NH- or 10H2-, R7, R, and R9 are respectively -H1-NH2, -NHR1', -NR1'R2'
-OH, halogen, or an alkyl group or alkoxy group having 1 to 5 carbon atoms. Such compounds include 4-aminodiphenylamine, 4,4'-diaminodiphenylamine, 4-amino-3'-methoxydiphenylamine, 4-amino-4'-hydroxydiphenylamine, p-aminoazobenzene, 2,4-diamino Azobenzene, 4-aminodiphenyl ether, 4
．． 4'-diaminodiphenyl ether, 2-aminobenzophenone, 4.4'-diaminobenzanilide, 4.
4'-diaminodiphenylmethane, 4.4'-diamino-43'-diethyldiphenylmethane, S, S'-cy/
Rolow 4,4'-cyamino diphenylmethane and the like are exemplified. If an aliphatic amine compound is used, the solubility will be poor when the reaction product is prepared as a coating solution in an aqueous solution of an alkali metal hydroxide or a solution in a polar solvent at °C, and the formation of a scale layer cannot be prevented, so it is preferable. do not have.

As a method for producing a reaction product of a cyclopentadiene compound (A), a phenol compound (B), and an aromatic amine compound (C) used as a coating agent in the present invention, cAl( At least one of each of B) and (C) is reacted simultaneously, or (A),
After starting the reaction with at least 1fl1 or more of each of the two components (B) and (C), at least 111 or more of the remaining one component is charged all at once or in portions,
00-400℃ preferably 150S! A typical method involves reacting at a temperature of 500°C for 5 minutes to 10 hours. The acidic catalysts used here include mineral acids such as hydrochloric acid, sulfuric acid, and phosphoric acid, organic acids such as para-toluenesulfonic acid, methanesulfonic acid, oxalic acid, and @acid, and aluminum chloride, ferric chloride, stannous chloride, Lewis acids such as boronic trifluoride and boronic tribromide are exemplified. In addition, the amount of acidic catalyst depends on the reaction temperature, the above-mentioned raw materials (A), (B) and (C).
) and the desired reaction time, but
Usually, the amount is in the range of α001 to 1 mole per mole of the phenol compound.

In the present invention, the reaction product that is particularly effective as a coating agent for preventing scale adhesion is made from a cyclopentadiene compound (A), a phenol compound (B), and an aromatic amine compound (C); , (B) and (C)
The charging ratio of (A) to the total amount of is 20 to 80 mol%
, Favorable Fusing - 30 to 60 mol %, and can be obtained by charging and reacting so that the molar ratio of (B) to (C) is 1 to 10, preferably tl to 5.

If the charging ratio of the above-mentioned cyclopentadiene compound (A) is less than 20 MOAS, the adhesion and water resistance of the coating film when used as a coating agent will be poor, and the lasting effect of preventing scale will be reduced. However, the ratio of the phenol compound and the aromatic amine compound relatively increases, and the effect of inhibiting polymerization is too strong, resulting in a delay in the polymerization rate and a decrease in the quality of the obtained polymer particles. In addition, if the charging ratio of (A) exceeds 80 molty, the polymerization inhibition effect will be insufficient,
It is not possible to prevent scale formation on the inner wall surface of the polymerization vessel.

If the molar ratio of the phenol compound (B) to the aromatic amine compound (C) is less than 1, the number of hydroxyl groups in the resulting reaction product will decrease and the hydrophilic effect of the coating will decrease. This is thought to be because monomers such as vinyl chloride come into contact with the inner wall surface of the polymerization vessel and polymerization occurs there, but the scale increases. Further, there are disadvantages in that the yield when producing the reaction product decreases, and the solubility of the reaction product when preparing a coating agent solution is poor, resulting in a decrease in scale prevention effect. Furthermore, in this case, since the ratio of the aromatic amine compound is relatively large, the polymerization inhibiting effect of the amino group is too strong, resulting in adverse effects such as a delay in the polymerization rate and a decrease in quality. That is, hydroxyl groups and amino groups have an excellent polymerization inhibiting effect on vinyl chloride monomers, and amino groups have a particularly strong inhibiting effect. On the other hand, when the molar ratio of (B) to (C) exceeds 10, the scale prevention effect decreases.

In other words, by reacting the three raw materials described above in a specific ratio, the adhesion effect of the coating film of the cyclopentadiene compound, the hydrophilic effect of the coating film and the polymerization inhibition effect of the phenol compound, and the aromatic amine compound. When used as a coating agent for scale prevention, it exhibits scale adhesion prevention effect and its excellent long-lasting effect without deteriorating the quality of the product.

According to the method for producing a reaction product according to the present invention, the molecular weight and softening point of the obtained reaction product vary depending on the charging ratio of the three ingredients described above, reaction temperature, reaction time, and amount of catalyst, and usually the molecular weight 200-3000C, and the softening point is in the range of about 50-250C.

The reaction product obtained in this way is usually polymerized by a known method such as spraying or brushing with an aqueous solution of an alkali metal hydroxide such as caustic soda, or a solution of a polar solvent such as methanol or acetone. A coating film is formed on the inner wall of the vessel and other parts that come in contact with the monomer, such as the stirrer, baffle, and reflux condenser.

The amount of application is the same as when using conventional coating agents,
- In general, the solid content is [1001 to 20 f/-1, preferably ij 0.1 to 10 P/, 1. Further, after coating, the surface after coating may be heated and dried or may be simply washed with water, if necessary.

Vinyl chloride polymers are produced using a polymerization vessel with a coating film formed on its internal surface in this way, but the method according to the present invention involves polymerization in an aqueous medium, that is, suspension polymerization, emulsion polymerization, It can be applied to both fine #II turbid polymerization and bulk polymerization.

In the present invention, monomers that can be copolymerized with vinyl chloride monomers include, for example, alkyl vinyl esters such as vinyl acetate, alkyl vinyl ethers such as cetyl vinyl ether, α-monoolefins such as ethylene t or propylene, and acrylic acid. Examples include, but are not limited to, acrylic alkyl esters such as methyl and methyl methacrylate.

Further, the suspending agent, emulsifying agent, and polymerization initiator used in the present invention are those used in ordinary suspension polymerization or emulsion polymerization of vinyl chloride. Examples of the suspending agent include polyvinyl alcohol, partially saponified polyvinyl acetate, methylcellulose, cellulose derivatives such as hydroxypropylmethylcellulose, and synthetic polymeric substances such as maleic anhydride-vinyl acetate copolymer. Also,
Examples of emulsifiers include sorbitan esters or glycerin esters of higher fatty acids, nonionic surfactants such as polyoxyethylene adducts thereof, and anionic surfactants such as sodium lauryl sulfate and sodium dodecylbenzenesulfonate. Ru. Examples of the polymerization initiator include di-2-ethylhexyl peroxydicarbonate and jetoxyethyl peroxydicarbonate.

α-cumylperoxyneodecanate, t-butylperoxyneodecanate, t-butylperoxybipare), L5.5-)limethylhexanoyl peroxide and acetylcyclohexylsulfonyl peroxide, etc. ai oxide and α,α′-azobisisobutyronitrile and α,α′-7zobis-2
．． Examples include one or a mixture of two or more azo compounds such as 4-dimethylvaleronitrile.

Also, mercaptoalkanol if desired.

Chain transfer 11T such as thioglycolic acid alkyl ester
It is also possible to use oil-soluble suspension aids such as polyvinyl alcohols having a saponification degree of 20 to 50 molar, a pH adjuster, and a polymerization inhibitor. Polymerization usually takes place at 35-80℃
The amount of each component and the number of parts to be charged may be the same as those conventionally used for vinyl chloride polymerization, and are not particularly limited.

(Effects of the Invention) Thus, according to the present invention, scale adhesion can be prevented more effectively and the effect can be maintained for a longer period of time than in the prior art. It is extremely useful because it does not have any adverse effects such as deteriorating the particle size distribution or fish eye.

(Example) The present invention will be described in more detail with reference to Examples below. In addition, parts and parts in Examples, Comparative Examples, and Reference Side are based on weight unless otherwise specified. In addition, the physical property values of the vinyl chloride polymer shown in each example were measured by the following method.

(1) Fischer eye vinyl chloride polymer 1002 and dioctyl phthalate) 4
52. After adding and mixing cadmium stearate 2f, barium stearate 1t, and green toner 12, kneading the mixture with a 6-inch roll at 145°C for 6 minutes to obtain a thickness of α
Draw out to a 4 mm sheet, and the surface of the sheet is 100 cI.
The number of transparent particles observed in IL'' is shown.

(2) Average particle size By line analysis using a wire mesh based on Tyler Mesche standard,
It is shown as a 50% passing diameter.

(3) Line analysis using a wire mesh based on Tyler mesh for coarse particles,
It is indicated by the percentage remaining on the wire mesh of 60 mesh.

(4) Porous Mercury intrusion porosimeter (5-7) manufactured by Aminco, USA
121B type) was used, and the amount was expressed as the volume of mercury injected per granular vinyl chloride polymer 12 during pressurization from normal pressure to 14,000 psi.

(Dan Plasticizer absorbing Toyo Seiki's new Labo Plastomill (P-600 type)
400v of vinyl chloride polymer and polyester polymer plasticizer PN-250 (
7 (manufactured by Deca Argus Chemical Co., Ltd.) was added, and the torque was recorded while stirring at 60 revolutions, and the time required for the mixing torque to decrease and stabilize was expressed as the time.

Reference Example 1 (Comparative Example: Reaction Product Floor 1) A four-hole flask with an internal volume of 31 cm had a viscosity of about 1 at 25°C.
Oily cyclopentadiene polymer (thermal copolymer of 50% dicyclopentadiene and 50% 1.3-pentadiene) with an average molecular weight of about 270 at 0,000 centipoise
5002 (approximately 11 mol), pyrogal 500 f
(2,4 mol) and p-toluenesulfonic acid cL6f
(α0035 mol) t-charge, 16 mol under nitrogen atmosphere
The reaction was carried out at a temperature of 0°C for 2 hours.

After the reaction is complete, cool to below 100°C, then add 80°C water 2
After adding 4 and washing with water, the operation of separating the supernatant liquid and removing unreacted substances was repeated until the pH of the 1 wrinkle liquid became 7.

Subsequently, the contents taken out in the oven were dried at 80° C. for 5 hours under a reduced pressure of 75 H1. As a result, a deep purple resinous reaction product N111 was obtained.

Reference Example 2 (Comparative Example: Reaction Product N112) Resorcinol 155P (15 mol) was placed in a four-hole flask with an internal volume of 3 J.
m-phenylenediamine 162f (15 mol) and 5
5% hydrochloric acid 15.6F (115 mol) was charged, and the reaction was carried out at a temperature of 315° C. for 30 minutes in a nitrogen atmosphere. Then, by washing with water and drying in the same manner as in Reference Example 1,! F
A brown resin-like reaction product magnetodynamic 2 was obtained.

Reference Example 3 (Invention: Reaction product tJnl) Dicyclopentadiene 120f (α9 moles), cyclopentadiene trimer 60 Cα3 moles)
, pyrogallol 151F (12 moles), m-7z nylenediamine 652 (α6 moles) and 35% hydrochloric acid 10.4
f (α1 mol) was charged, the temperature was raised to 250° C. under a nitrogen atmosphere, and this temperature was maintained for 90 minutes to carry out the reaction. Next, by washing with water and drying in the same manner as in Reference Example 1, a reddish brown resinous reaction product Na5 was obtained. The yield of the reaction product was approximately 550 tons, and the Europeanization point (J
According to ISK2551) was 102.5°C. Moreover, the average molecular weight (according to GPC) was about 500.

Reference example 4 (present invention: reaction products 4 to 12) internal volume 31
A cyclopentadiene compound (A), a phenol compound (B), an aromatic amine compound (C) and phosphoric acid shown in Table 1 were placed in a four-hole flask. (α10 mol) was charged, and reaction products P&Ls 4 to 12 were obtained by performing the reaction, washing with water, and drying in the same manner as in Reference Example 3.

Reference Example 5 (Reaction Product Floors 13 to 18) In a four-hole flask with an internal volume of 3 mm, dicyclopentadiene, resorcinol, m-7 enylene diamine, and phosphorus @9.8? ((L 10 mol)) was reacted, washed with water, and dried in the same manner as in Reference Example 3 to obtain reaction products N115 to N18.

Example 1 The reaction products Na1 to Na12 obtained in Reference Examples 1 to 4 were dissolved in methanol to prepare a coating liquid with a solid content concentration of 4s.

Subsequently, this coating solution was applied to an electrolytically polished stainless steel test piece at a coating amount of 52/I♂ (in terms of solid content, the same applies hereinafter) and dried at 80°C for 10 minutes.This test piece were installed in the liquid phase and gas phase of a stainless steel polymerization vessel with an internal volume of 950 mm, the polymerization vessel was degassed, and 350 # of deionized water and 250 J of vinyl chloride monomer were added.
c9, partially saponified polyhinyl alcohol 140F, di-2-ethylhexyl peroxydicarbonate 50f and t-butyl peroxypivalate 50f were charged, and polymerization was carried out at 62° C. for 5 hours.

After the polymerization was completed, the thickness of the scale adhering to the test piece was measured, and the test piece was placed in the polymerization vessel again. After 9 days, polymerization was repeated for a total of 5 batches in the same manner as described above. As a result, the thickness of the scale was as shown in Table 3.

As is clear from Table aI3, it can be seen that the method of the present invention is excellent in the scale adhesion prevention effect and its sustainability.

Table 5 Umbrella Comparative Example Example 2 The reaction product N11j5-18 obtained in Reference Example 5 was
It was dissolved in a caustic soda aqueous solution of SS at 80°C to prepare a coating liquid with a solid content concentration of 1.5-. Next, the internal volume is 950
The above-mentioned coating solution was applied to the inner wall of the stainless steel expansion polymerization vessel and the portion that would come into contact with the low-weight body using a spray IM device at a coating amount of 12/d.

Next, after degassing the polymerization vessel, 550 IqI of deionized water, 9 to 250 IqI of vinyl chloride monomer, 70 to partially saponified polyvinyl alcohol, and 4 to 4 hydroxyglobil methylcellulose were added.
Of, di-2-ethylhexylhexyl oxydicarbonate) 12Of was charged, and polymerization was carried out at a temperature of 58° C. for 5 hours. After the polymerization was completed, unreacted monomers were collected and the contents were dehydrated and dried.

The physical properties of the polymer particles thus obtained and the amount of scale deposited in the polymerization vessel were as shown in Table 4.

From Table 4, it is clear that the method of the present invention has a large scale prevention effect and does not adversely affect the quality of the product.

4th Table Car Comparative Example Example 3 Reaction products Na1 (Reference Example 1), Na2 (Reference Example 2),
Arashi 3 (Reference Example 5) and N114 (Reference Example 5) were dissolved in a caustic soda water bath solution in the same manner as in Example 2 to prepare a coating solution.

Next, use a sprayer to spray rL51/
The coating solution described above was applied in an amount of 100 ml, and the coated surface was further washed with deionized water, and the washing water was discharged out of the polymerization system.

Next, 16 tons of deionized water was charged while degassing the polymerization vessel, and then 13.5 tons of vinyl chloride monomer, 7.5 kg of S-part saponified polyvinyl alcohol, and di-2-ethylhexyl peroxydicarbonate were added. 3 and 5 were charged at the same time, and polymerization was carried out at a temperature of 57.5°C for 8 hours. After the polymerization is completed and the contents are discharged, the inside of the polymerization vessel weighs 250 kg.
After washing with /- high pressure water for 15 minutes, the above coating agent was applied again, and the polymerization was repeated in the same manner.

The number of polymerization batches carried out in this manner, the overall heat transfer coefficient of the polymerization vessel jacket, and the Fischer eye of the obtained polymer particles were as shown in Table 5.

From Table 5, according to the method of the present invention, the heat removal ability of the polymerization vessel jacket can be maintained for a long period of time even if polymerization is repeated, and fish eye does not increase, resulting in high efficiency and high quality. products can be manufactured.

Table 5 Ratio Overall heat transfer coefficient (Kca//-・h
r・℃) 2) Number of patches that can maintain overall heat transfer coefficient of 500 or more and fisheye of 200 or less Example 4 Stainless steel expansion polymerization vessel with an internal volume of 20 and heat transfer area attached to the gas phase part of the polymerization vessel 1.5 f/- of a caustic soda aqueous solution (IP! fabric solution) with a solid content concentration of 2% of the reaction product jll15 obtained in Reference Example 3 was applied to the internal surface of a multi-tubular reflux condenser having a 18♂. After applying the same amount, the polymerization vessel was evacuated.

Next, 9000 kg of deionized water, vinyl chloride monomer yo
A mixture of OO#, vinyl acetate monomer 500#, sodium dodecylbenzenesulfonate 40kg, lauryl alcohol BOkg, &5.5-)limethylhexanoyl peroxide 2kg, and di-2-ethylhexyl peroxydicarbonate 2hg 1600 ps
The mixture was homogenized by passing through a pressurized homogenizer under the conditions of i, charged into a polymerization vessel, and heated to 60°C.

Continue to maintain this temperature while removing the polymerization reaction heat using the polymerization reactor jacket and 7lux condenser.
Time polymerization was performed.

After the polymerization was completed, the produced polymer latex was discharged and the inside of the polymerization vessel was washed with pressurized water at 250 νd for 15 minutes.
The coating liquid was applied again, and the polymerization was repeated in the same manner.

After polymerizing 50 batches in this way, we observed the scale adhesion inside the polymerization vessel and reflux condenser, and found that there was no scale at all, and no adverse effects on product quality such as particle size were observed. There wasn't.

Comparative Example 1 Polymerization was carried out in the same manner as in Example 4 except that the coating solution for preventing scale was not used.

At the 5th batch of polymerization, reflux and
The heat removal capacity (overall heat transfer coefficient) of the condenser decreased by 27%, and 360? /#- scale was attached, so the scale was removed manually.

Comparative Example 2 In Example 4, polymerization was carried out in the same manner as in Example 4, except that the reaction product Na2 obtained in Reference Example 2 was used as a coating liquid for preventing scale.

After the polymerization was completed, when attempting to discharge the latex in the polymerization vessel, the coarse aggregated polymer of 1 to 10 c'H clogged the filter and piping, making the discharge operation cumbersome and difficult. In one batch of polymerization, a scale of 78,027 mm was adhered to the inner wall of the polymerization vessel, and cream-like deposits of polymer with a thickness of 5 to 101 m were locally observed.

Claims (1)

[Claims] 1 When polymerizing vinyl chloride monomer or a mixture of vinyl chloride monomer and a monomer copolymerizable with vinyl chloride in an aqueous medium or in bulk, cyclopentadiene monomer or oily or wax A reaction product obtained by reacting a cyclopentadiene polymer (A), a phenol compound (B), and an aromatic amine compound (C) is applied in advance to the inner wall of the polymerization vessel and other parts that will come into contact with the monomers. A method for producing a vinyl chloride polymer, characterized by: