JPH08109203A - Method for producing vinyl chloride polymer - Google Patents

Abstract

(57) [Summary] [Structure] During suspension polymerization of a vinyl chloride monomer in an aqueous medium, a methanol / dimethylformaldehyde solution, gelatin and an inorganic colloid are dissolved in a water / methanol solvent to adjust the pH to 11.0. The adjusted product was applied as a polymer scale anti-adhesion agent in a polymerization vessel, and 3-hydroxy-1,1-dimethylbutylperoxyneodecanoate and t-butylperoxyneodecanoate were used as polymerization initiators. Polymerization is carried out using a combination with an ate. [Effect] Even if the polymerization time is shortened, a polymer scale does not adhere to the inside of the polymerization vessel, and a high-quality vinyl chloride polymer can be obtained.

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 producing a vinyl chloride polymer with high quality and high productivity while preventing adhesion of polymer scale. The present invention relates to a method for producing a vinyl chloride polymer, which is suitable for

[0002]

BACKGROUND OF THE INVENTION Vinyl chloride polymers are generally prepared by suspension polymerization of a vinyl chloride monomer or a mixture of vinyl monomers mainly containing vinyl chloride monomer in an aqueous medium using an oil-soluble polymerization initiator. Manufactured by. The polymerization initiator used at this time, depending on the type, the exothermic pattern of the polymerization reaction, the polymerization time, the productivity, the polymer scale adhesion during the polymerization, the initial colorability of the polymer, the thermal stability, the odor, the resistance to It has a great influence on quality characteristics such as extractability.

In recent years, the polymerization time has been shortened for the purpose of improving the productivity of vinyl chloride polymers. As one method for shortening the polymerization time, it can be considered to increase the addition amount of the polymerization initiator. However, there is a problem that the quality of the polymer is lowered, especially the initial colorability is lowered, and the thermal stability is lowered with the increase of the addition amount of the polymerization initiator. Then, there are problems that a bad odor is generated due to an increase in the residue of the polymerization initiator and a decomposition product, an extraction component is increased, and further, an amount of polymer scale attached in the polymerization vessel is increased.

By the way, in order to prevent adhesion of polymer scale in a polymerization vessel, dyes, pigments, water-soluble polymer compounds, nitrites, nitrogen-containing aromatic compounds, heterocyclic compounds, iodo compounds and pyrogallol have been conventionally used. Derivatives, phenolic compounds, aromatic amine compounds and the like have been applied to the inner surface of a polymerization vessel as a polymer scale adhesion preventing agent. However, in these conventional polymer scale anti-adhesion agents, the adhesion of the polymer scale in the polymerization vessel during the production of the vinyl chloride polymer, especially the polymer scale adhesion in the gas phase part and the gas phase-liquid phase interface part Cannot be effectively suppressed.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art. The object of the present invention is to provide a vinyl chloride polymer having good quality such as initial colorability in a short polymerization time. Moreover, it is an object of the present invention to provide a manufacturing method capable of manufacturing while suppressing the adhesion of the polymer scale in the polymerization vessel.

[0006]

According to the present invention, in order to solve such a problem, a vinyl chloride monomer is provided in a polymerization vessel having a coating film for preventing polymer scale adhesion on the inner wall surface of the polymerization vessel. Alternatively, in a method for producing a vinyl chloride-based polymer, which comprises suspension-polymerizing a mixture of vinyl-based monomers mainly composed of the same in an aqueous medium using an oil-soluble polymerization initiator, the polymer scale adhesion prevention is performed. Of the general formula (1):

[Chemical 4] [In the formula, R ^{1 s} may be the same or different,
_{H, -OH, -COOH, -SO 3} H, -NH 2, -Cl, -NO 2,
-COCH _3, -N (CH ₃₎ a ₂ and a group selected from the group consisting of alkyl group having 1 to 3 carbon atoms, X is an alkylene group having 1 to 5 carbon atoms, -N (CH ₃₎ −, −C (CH ₃ ) ₂
-, - CONH -, - P (= O) H-, -SO 2 -, - O -, - S-
And -Si (R) _2- (wherein R is an alkyl group having 1 to 10 carbon atoms). n is an integer of 1-2. ] A condensation product of a diphenyl compound having at least two amino groups represented by the following and a quinone compound, and (b) a water-soluble polymer compound,
The oil-soluble polymerization initiator is formed by applying an alkaline solution containing at least one selected from the group consisting of inorganic colloids and alkali metal silicates onto the inner wall surface and drying the solution. , (A) 0.1 mol / l benzene solution has a 10-hour half-life temperature of 30-
A vinyl chloride polymer comprising a compound having no benzene ring or an alkoxy group in its structure at 50 ° C. and (B) 3-hydroxy-1,1-dimethylbutylperoxyneodecanoate A method of manufacturing the same is provided.

That is, in the method for producing a vinyl chloride polymer of the present invention, suspension polymerization is carried out using a specific oil-soluble polymerization initiator in a polymerization vessel having a specific polymer scale adhesion preventive coating film. There is a new feature in the point. The details will be described below.

Polymer scale anti-adhesive coatings The scale anti-adhesive coatings used in the method of the present invention are:
Formed by applying an alkaline liquid containing a condensation product (a) of a diphenyl compound represented by the general formula (1) and a quinone compound, and a water-soluble polymer compound (b) on the inner wall surface and drying it. Is.

[(A) Condensation product] Specific examples of the diphenyl compound represented by the general formula (1) (hereinafter referred to as diphenyl compound) include, for example, 4,4′-diaminodiphenyl sulfide and 4,4′-diaminodiphenyl sulfide. '-Diaminodiphenyl ether, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl sulfone, bis (4-aminophenyl) diethylsilane, bis (4-aminophenyl) phosphine oxide, bis (4-aminophenyl) -N-methylamine,
4,4'-diaminobenzanilide, 4,4'-diaminodiphenylmethane and the like can be mentioned. Preferred among these are 4,4'-diaminodiphenyl sulfone, 4,4'-diaminobenzanilide, 4,4'-diaminodiphenyl ether and 4,4'-diaminodiphenylmethane. The diphenyl compounds may be used alone or in combination of two or more.

Examples of the quinone compound include the following general formulas (4) and (5):

Embedded image [In the formula, R ⁶ may be the same or different,
_{H, -NH 2, -Cl, -Br} , -OH, -NO 2, -COCH 3, -
OCH ₃ , -N (CH ₃ ) ₂ and a group selected from the group consisting of alkyl groups having 1 to 3 carbon atoms], a benzoquinone compound represented by the following general formula (6) and (7)

[Chemical 6] [In the formula, R ⁶ has the same meaning as described above, R ⁷ may be the same or different from each other, and -H, -Cl, -Br, -OH, -CO
A group selected from the group consisting of CH ₃ , —OCH ₃ , —CH ₃ , —COOH and —SO ₃ H] and the like.

Specific examples of the benzoquinone compound include, for example, o-, m- and p-benzoquinone and hydroxy-p.
-Benzoquinone, Chlor-p- Benzoquinone, Brom-p-
Examples include benzoquinone, juroquinone, chloranil and the like. Specific examples of the naphthoquinone compound include 6-methyl-1,4-naphthoquinone, 2-methyl-1,4-naphthoquinone, lawson, juglone, plumbagin, α-naphthoquinone, β-naphthoquinone and the like. Among these quinone compounds, o- and p-benzoquinone, α-naphthoquinone, β-naphthoquinone and lawson are preferable. The above quinone compounds may be used alone or in combination of two or more.

The condensation product (a) is prepared, for example, from the diphenyl compound and the quinone compound in a suitable solvent, if necessary in the presence of a catalyst, usually at room temperature to 200 ° C.
It is produced by reacting for about 100 hours, preferably at room temperature to 150 ° C. for 3 to 30 hours.

Since the above-mentioned quinone compound also acts as a condensation catalyst, it is usually unnecessary to add another condensation catalyst, but it is also possible to add another condensation catalyst. Other condensation catalysts include elemental or molecular simple halogens such as iodine, bromine, chlorine and fluorine; halogen oxyacids and oxyacid salts such as iodic acid, periodic acid, potassium periodate and sodium perchlorate; Inorganic peroxides such as hydrogen peroxide, sodium peroxide, potassium persulfate and ammonium persulfate; organic peroxides such as peracetic acid, henzoyl peroxide, cumene hydroperoxide, perbenzoic acid and p-menthane hydroperoxide Chlorides and sulfates of metals selected from iron and copper, such as ferrous chloride, ferric chloride, copper sulfate, cuprous chloride; α, α′-azobisisobutyronitrile, α, α Azo compounds such as'-azobis-2,4-dimethylvaleronitrile; nitrobenzene, o-, m
-Or p-oxynitrobenzene, o-, m- or p-nitroanisole, o-, m- or p-nitrobenzoic acid, aromatic nitro compounds such as o-, m- or p-nitrobenzenesulfonic acid, etc. To be

As the solvent for the condensation reaction, for example, organic solvents such as alcohols, ketones and esters are used, and among them, it is preferable to use an organic solvent miscible with water. Examples of the organic solvent miscible with water include alcohols such as methanol, ethanol and propanol; ketones such as acetone and methyl ethyl ketone;
Esters such as methyl acetate and ethyl acetate; for example, aprotic solvents such as dimethylformamide, dimethylsulfoxide, acetonitrile and the like are exemplified, and among them, alcohols are particularly preferable. It is also possible to use a water-miscible organic solvent and water-miscible solvent.

The pH of the medium for carrying out the condensation reaction is usually 1 to 1.
It is in the range of 3, and the pH adjuster can be used without particular limitation.

The mixing ratio of the above-mentioned diphenyl compound and quinone compound depends on the types of components and solvents used, reaction temperature,
Diphenyl compound 1 is usually used, though it is affected by the reaction time.
The amount of the quinone compound is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on parts by weight.
If the blending ratio of the quinone compound is too large or too small, the condensation product obtained may have a reduced polymer scale adhesion preventing effect.

[(B) Water-soluble polymer compound, etc.]
In addition to the condensation product (a), it further contains (b) at least one selected from the group consisting of water-soluble polymer compounds, inorganic colloids, and alkali metal silicates. as a result,
The effect of preventing scale adhesion of the obtained coating film is further improved.

Water-soluble polymer compound: Examples of the water-soluble polymer compound include amphoteric polymer compounds such as gelatin and casein; anionic polymer compounds such as polyacrylic acid, polystyrene sulfonic acid, carboxymethyl cellulose and alginic acid; polyvinyl. Examples thereof include cationic nitrogen-containing polymer compounds such as pyrrolidone and polyacrylamide; hydroxyl group-containing polymer compounds such as polyvinyl alcohol, hydroxyethyl cellulose, hydroxypropyl cellulose and pectin. Among the water-soluble polymer compounds, gelatin, casein, polyacrylic acid, carboxymethyl cellulose, polyvinylpyrrolidone and pectin are preferable. These water-soluble polymer compounds may be used alone or in combination of two or more.

Inorganic colloid: Inorganic colloid is, for example,
It is a particle colloid manufactured by a dispersion method using water as a dispersion medium or an aggregation method, and the size of the colloid particles is 1 to 500.
μm. As the inorganic colloid, specifically, colloids of oxides and hydroxides of metals selected from aluminum, thorium, titanium, zirconium, antimony, tin, iron, etc., colloids of tungstic acid, vanadium pentoxide, gold and silver. Examples thereof include silver iodide sol, selenium, sulfur, and colloids of silica and the like. Preferred among these are colloids of oxides and hydroxides of metals selected from aluminum, titanium, zirconium, tin and iron, and colloidal silica. These inorganic colloids may be used alone or in combination of two or more.

Alkali metal silicates: Examples of alkali metal silicates include metasilicates (M ₂ SiO ₃ ) of alkali metals such as lithium, sodium and potassium, orthosilicates (M ₄ SiO ₄ ), Silicate (M ₂ Si ₂ O
₃ ), trisilicate (M ₃ Si ₃ O ₇ ), sesquisilicic acid (M
₄ Si ₃ O ₁₀ ), etc. (here, M represents an alkali metal such as lithium, sodium, potassium, etc.), water glass and the like. These alkali metal silicates may be used alone or in combination of two or more.

These components (b) are the above condensation products.
(a) It is usually 0.01 to 10 parts by weight, preferably 0.05 to 2 parts by weight, per 1 part by weight. Preferably, the water-soluble polymer compound is used in combination with at least one of the inorganic colloid and the alkali metal vinyl silicate.
That is, it is preferable to use at least a combination of a water-soluble polymer compound and an inorganic colloid, or a combination of a water-soluble polymer compound and an alkali metal silicate.

When the water-soluble polymer compound and the inorganic colloid are used in combination, it is preferable to use 5 to 3000 parts by weight of the inorganic colloid per 100 parts by weight of the water-soluble polymer compound, and further 50 to 1000 parts by weight. Partial use is preferred.
When used in combination with the water-soluble polymer compound and the alkali metal silicate, it is preferable to use 5 to 3000 parts by weight of the alkali metal silicate per 100 parts by weight of the water-soluble polymer compound. It is preferred to use up to 1000 parts by weight. Most preferably, the three kinds of water-soluble polymer compound, inorganic colloid and alkali metal silicate are used in combination. The preferred formulation at that time is based on the above formulation.

[Coating Liquid] The coating liquid used for forming the polymer scale anti-adhesive coating film is prepared by, for example, adding the following solvent to the condensation product-containing solution obtained as a result of the above condensation reaction, if necessary. If the pH is not alkaline, it is adjusted to be alkaline. In addition, the coating liquid is, for example, after the condensation product-containing liquid is poured into cold water to precipitate the condensation product, the precipitate is filtered off, and the dried product is added with the following solvent, followed by It may be prepared by adjusting the pH to be alkaline.

By making the coating solution alkaline,
The solubility of the condensation product (a) in a solvent is improved. Therefore, since the coating solution becomes a uniform solution, the coating film obtained is also uniform, and the polymer scale adhesion preventing effect is improved. The coating solution preferably has a pH range of 7.5 to 13.5, and particularly preferably a pH range of 8.0 to 12.5. Examples of the alkaline compound used for pH adjustment include LiOH, NaOH, KOH and Na ₂ CO
₃ , alkali metal compounds such as Na ₂ HPO ₄ , NH ₄ OH and ammonia compounds such as ethylenediamine,
Examples include organic amine compounds such as monoethanolamine, diethanolamine and triethanolamine.

Examples of the solvent used for preparing the polymer scale anti-adhesive agent of the present invention include water; methanol, ethanol, propanol, butanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2. −
Alcohol solvents such as propanol, 3-methyl-1-butanol, 2-methyl-2-butanol, 2-pentanol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone; methyl formate, ethyl formate, methyl acetate, Examples thereof include ester solvents such as ethyl acetate and methyl acetoacetate; ether solvents such as 4-methyldioxolane and ethylene glycol diethyl ether; furans; aprotic solvents such as dimethylformamide, dimethyl sulfoxide and acetonitrile. These solvents are appropriately used alone or as a mixed solvent of two or more kinds.

Among the above solvents, water and a mixed solvent of water and an organic solvent miscible with water are preferable.
Examples of the organic solvent which is miscible with water among the above organic solvents include alcohol solvents such as methanol, ethanol and propanol; ketone solvents such as acetone and methyl ethyl ketone; ester solvents such as methyl acetate and ethyl acetate. Is mentioned. When using a mixed solvent of water and a water-miscible organic solvent, the content of the organic solvent shall be such that there is no danger of ignition, explosion, etc. and there is no safety problem in handling such as toxicity. Is preferred, and specifically, the organic solvent is preferably 50% by weight or less, and further 3
It is preferably 0% by weight or less.

The concentration of the condensation product in the alkaline solution is not particularly limited as long as the total coating amount described below can be obtained, but it is usually about 0.001 to 5% by weight, preferably 0.
It is about 0 to 1% by weight.

[Formation of coating film] The coating solution obtained as described above is applied to at least the inner wall surface of the polymerization vessel and dried to form a coating film. Drying is sufficiently carried out, for example, in a temperature range from room temperature to 100 ° C., and further, if necessary, washing with water.
The coating film thus formed effectively prevents the scale from adhering.

The polymer scale anti-adhesion coating film is preferably formed not only on the inner wall surface of the polymerization vessel, but also on other portions where the monomer contacts during the polymerization. For example, a stirring blade, a stirring shaft, a baffle, a condenser, a header, a search coil, a bolt, a nut and the like can be mentioned. More preferably, the polymer scale anti-adhesion agent is a site other than the site where the monomer contacts during the polymerization, but a site where the polymer scale may adhere, for example, a device of a recovery system of unreacted monomer. It is also preferable to form the coating film on the inner surface of the pipe and the like. Specifically, the inner surfaces of a monomer distillation column, a condenser, a monomer storage tank, a valve and the like can be mentioned.

The method of applying the coating liquid to the inner wall surface of the polymerization vessel is not particularly limited, and examples thereof include brush coating, spray coating, and a method of withdrawing after filling the polymerization vessel with the polymer scale adhesion preventive agent. , And others, JP-A-57-6
It is also possible to use the automatic coating methods described in JP-A Nos. 1001 and 55-36288, JP-A-56-501116, JP-A-56-501117, JP-A-59-11303 and the like.

The method of drying the wet surface after applying the coating solution is not limited, and the following method can be used, for example. That is, after applying the polymer scale anti-adhesive agent, a method of applying an appropriately heated hot air to the application surface, or the inner wall surface of the polymerization vessel and the other surface to which the polymer scale anti-adhesive agent is applied are preliminarily set to, for example, 30
It is possible to use a method in which the polymer scale adhesion preventing agent is directly applied to the heated surface by heating to -80 ° C. After drying the coated surface, the coated surface is washed with water as needed.

The coating film thus obtained has a total coating amount after drying of usually 0.001 to 5 g / m ² , particularly,
It is preferably 0.05 to ² g / m ² .

The above coating operation may be carried out every 1 to 10 or more batches of polymerization. Since the formed coating film has high durability and the action of preventing the polymer scale from adhering continues, it is not always necessary to perform it for each batch of polymerization, so that the productivity is improved.

Polymerization Initiator The oil-soluble polymerization initiator used in the method of the present invention is (A)
An organic peroxide having a benzene ring or an alkoxy group in its structure at a temperature of 30 to 50 ° C. for a 10-hour half-life of a 0.1 mol / liter benzene solution, and (B) 3-hydroxy-
It consists of 1,1-dimethylbutyl peroxyneodecanoate. When the component (A) is an organic peroxide having a 10-hour half-life temperature of less than 30 ° C., the activity of the polymerization initiator becomes difficult to sustain. Further, if the temperature exceeds 50 ° C., an excessively large amount of the polymerization initiator is required, so that the quality of the obtained polymer such as initial colorability and extraction resistance is deteriorated. In addition, when the polymer has a benzene ring, a UV absorption peak is detected during the extraction test of the obtained polymer, which may limit the use of the polymer in the fields of medical care, food, and the like. Further, when the molecule has an alkoxy group, the polymer scale is likely to adhere in the polymerization vessel.

Examples of the organic peroxide (A) include, for example,
The following general formula (2):

[Chemical 7] (In the formula, R ² and R ³ are each a substituted or unsubstituted n-alkyl group having 1 to 15 carbon atoms, sec-alkyl group, te
rt-alkyl group or a cyclic alkyl group) represented by the following general formula (3):

Embedded image (In the formula, R ⁴ and R ⁵ are respectively a substituted or unsubstituted n-alkyl group having 1 to 20 carbon atoms, sec-alkyl group, te
and a perester compound represented by rt-alkyl group or cyclic alkyl group).

Specific examples of the above-mentioned diacyl compound include isobutyryl peroxide (10-hour half-life temperature: 33 ° C., hereinafter also shown in parentheses) and the like. Specific examples of the above perester compound include, for example, t-hexyl peroxy neodecanoate (45
℃), t-butyl peroxyneodecanoate (46
℃), t-hexyl peroxy neohexanoate (49
° C), 2,4,4-trimethylpentylperoxy-2
-Neodecanoate (36 ° C), 1-cyclohexyl-1
-Methyl ethyl peroxy neodecanoate (41 ° C) and the like. Among the above-mentioned organic peroxides (A), isobutyryl peroxide, t-hexyl peroxy neodecanoate, t-butyl peroxy neodecanoate,
t-hexyl peroxy neohexanoate, 2,4
4-Trimethylpentylperoxy-2-neodecanoate and 1-cyclohexyl-1-methylethylperoxyneodecanoate are preferred. The above-mentioned organic peroxide (A) may be used alone or in combination of two or more.

It is generally known that the 10-hour half-life temperature of an initiator composed of an organic peroxide is determined as follows. Concentration of organic peroxide is 0.1 mol /
A liter of benzene solution is put in a sealed container, and kept at a predetermined temperature for thermal decomposition, and the change in concentration of peroxide with time is measured. Since this decomposition reaction can be approximately regarded as a first-order reaction, the following relational expression holds. dx / dt = k (ax) ln [a / (ax)] = kt (where x is the concentration of the decomposed organic peroxide, a is the initial concentration of the organic peroxide, and k is the decomposition). Rate constant, t indicates time) Since the half-life t _1/2 is when x = a / 2 in the equation,
The following relational expression: kt _1/2 = ln2 holds. Since the constant k is obtained from the change in the concentration of the organic peroxide measured above and the equation, the half-life t _1/2 can be obtained from the equation. Therefore, the 10-hour half-life temperature is obtained as the temperature at which t _1/2 of a certain organic peroxide is 10 hours.

The method of the present invention comprises, as an oil-soluble polymerization initiator, the above organic peroxide (A) and (B) 3-hydroxy-
1,1-dimethylbutyl peroxyneodecanoate _{[CH 3 -CH (OH) -CH 2} -C (CH 3) 2 -OO-CO-tC 9 H 19 ]
By using and in combination, it is possible to appropriately control the heat generation due to the rise and progress of the polymerization. The mixing ratio and the amount of the component (A) and the component (B) used are slightly different depending on the reaction conditions, but generally,
The weight ratio of component (A) / component (B) is preferably 1/9 to 9/1, and more preferably 1/6 to 5/1.
If this blending ratio is too small, it may be difficult to suppress the adhesion of polymer scale in the polymerization vessel, and if it is too large, the initial colorability and thermal stability of the resulting polymer may be reduced. . The total amount of (A) and (B) components used is
For example, in the production of vinyl chloride homopolymer having an average polymerization of 1,000, 0.06 to 0.5% by weight of vinyl monomer is suitable.

The method of charging the polymerization initiator into the polymerization vessel is not particularly limited, and any of the conventionally known methods can be used. For example, a solution prepared by diluting with a solvent is used. Or as an emulsion or suspension by dispersing in water. Further, a polymerization initiator together with water and / or a suspending agent,
Alternatively, it may be charged after the water and / or the suspending agent have been charged, or after the monomer has been charged, it may be pressed into the polymerization vessel with a pump.

Polymerization Other conditions in the method for producing the vinyl chloride polymer of the present invention (for example, a method for charging an aqueous medium, a monomer, a dispersion aid, etc. to a polymerization vessel, a charging ratio, etc.) are usually an aqueous medium. It may be the same as the suspension polymerization of vinyl chloride and the like. The polymerization is preferably carried out under the reaction conditions of a polymerization temperature of 35 to 60 ° C. and a polymerization time of 2 to 6 hours.

As the monomer, in addition to vinyl chloride alone, a mixture containing vinyl chloride as a main component and another monomer copolymerizable therewith (usually 50% by weight or more of vinyl chloride) may be used. It is possible (hereinafter, vinyl chloride or a monomer mixture containing vinyl chloride is referred to as a vinyl chloride-based monomer). As the monomer copolymerizable with vinyl chloride, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1
-Heptene, 1-octene, 1-nonene, 1-decene,
1-undecene, 1-dodecene, 1-tridecene, 1-
Α-Olefin such as tetradecene; acrylic acid such as acrylic acid, methyl acrylate, ethyl acrylate or its ester; methacrylic acid such as methacrylic acid, methyl methacrylate or its ester; maleic acid or its ester; vinyl acetate, propionic acid Examples thereof include vinyl esters such as vinyl; vinyl ethers such as lauryl vinyl ether and isobutyl vinyl ether; maleic anhydride; acrylonitrile; styrene; vinylidene chloride; and other monomers copolymerizable with vinyl chloride. These are used alone or in combination of two or more.

The dispersant may be any of those usually used for suspension polymerization of vinyl chloride monomers in an aqueous medium. Examples of the dispersant include water-soluble cellulose ethers such as methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and hydroxypropyl methyl cellulose; water-soluble or oil-soluble partially saponified polyvinyl alcohols; acrylic acid polymers; Molecule; sorbitan monolaurate,
Examples thereof include oil-soluble emulsifiers such as sorbitan trioleate, glycerin tristearate and ethylene oxide propylene oxide block copolymers; water-soluble emulsifiers such as polyoxyethylene sorbitan monolaurate, polyoxyethylene glycerin oleate and sodium laurate. These are used alone or in combination of two or more.

Deionized water is usually used as the aqueous medium. Further, in this polymerization system, if necessary, a polymerization regulator, a chain transfer agent, and a pH that are appropriately used for vinyl chloride-based polymerization.
Regulator, gelation improver, antistatic agent, crosslinking agent, stabilizer,
Addition of fillers, antioxidants, buffers, scale inhibitors, etc. is also optional.

[0044]

EXAMPLES The present invention will be described in detail below by showing Examples and Comparative Examples. The present invention is not limited to the examples below. In each of the following examples, the jacket temperature means the temperature at the jacket inlet of the cooling water passing through the jacket of the polymerization vessel, and the temperature of the aqueous suspension in the polymerization vessel is maintained at a predetermined polymerization temperature. Is adjusted accordingly.

Example 1 First, the polymer scale adhesion preventive agent (I) of the present invention was produced as follows. In a reactor with an internal volume of 2 liter equipped with a reflux condenser, methanol 8
Charge 00g and 100g of dimethylformamide (DMF) and 40g of 4,4'-diaminodiphenyl sulfone, and stir at room temperature to mix 4,4'-diaminodiphenyl sulfone with methanol /
Dissolved in DMF. Methanol / DM thus obtained
To the F solution, 60 g of α-naphthoquinone was added, the temperature was raised to 65 ° C, and the reaction was carried out at 65 ° C for 24 hours. Next, the obtained reaction mixture was cooled and added dropwise to water. The deposited precipitate is filtered off.
After drying, a condensation product (a) was obtained. This condensation product (a)
, Gelatin (b), colloidal silica (trade name: Snowtex CXS-9, manufactured by Nissan Chemical Industries, Ltd., colloidal particle diameter: 5 to 7 mμ) (c) and water / methanol = 7 /
(A) / (b) / (c) = 1/1 with 3 (weight ratio) as a solvent
/ 1 (weight ratio), the total concentration of (a) + (b) + (c) is 0.5%
And the solution was adjusted to pH = 11.0 with NaOH.
The polymer scale adhesion inhibitor (I) was obtained. In a stainless steel polymerization vessel having an internal volume of 2.1 m ³ , the polymer scale adhesion inhibitor (I) prepared as described above was applied to the inner wall of the polymerization vessel, the stirring shaft, the stirring blades and other parts where the monomer contacts during the polymerization. After coating and heating at 40 ° C. for 15 minutes and drying to form a coating film, the inside of the polymerization vessel was washed with water. Next, 890 kg of deionized water and 350 g of partially saponified polyvinyl alcohol were added as an aqueous solution and added. After evacuating the inside of the vessel to 50 mmHg, 700 kg of vinyl chloride monomer was charged, and while stirring, the type and amount of the polymerization initiator shown in Table 1 was further injected with a pump, and at the same time the temperature started to start the polymerization. did. The polymerization reaction is carried out while maintaining the polymerization temperature at 55 ° C, and the internal pressure of the polymerization vessel is 6.0 kg / cm ² G.
Polymerization is stopped at the time of reaching, and unreacted monomer is recovered,
The obtained polymer in a slurry form was taken out of the vessel, the state of scale adhesion inside the vessel was observed, and the polymer was dehydrated and dried and subjected to a test by the following method. Table 1 shows the results.

Adhesion of scale in polymerization vessel: Evaluation was carried out according to the following criteria after repeating 100 batches of polymerization by each production method. ⊙: There is no scale adhesion and the metallic mirror surface has gloss. ○: There is some cloudiness on the metal mirror surface. △ …… × …… There is a film-like scale on the entire metal surface. -Measurement of bulk specific gravity: JIS K-6721 for the obtained polymer
Was measured according to. -Measurement of particle size distribution: JIS Z-88 for the obtained polymer
Sift using each of the # 60, # 100, and # 200 sieves according to 01,
The amount of passage was measured and expressed in% by weight. -Measurement of fish eye amount: 100 parts by weight of the obtained polymer, 50 parts by weight of DOP, 0.1 part by weight of barium stearate, 0.1 part by weight of cadmium stearate, cetanol
0.8 parts by weight, tin stabilizer 2.0 parts by weight, titanium dioxide 0.5
Parts by weight and carbon black 0.1 parts by weight at 140 ° C.
For 5 minutes mixing and kneading at inch roll, aliquoted as a sheet having a thickness of 0.3 mm, indicated by the number of white transparent particles in 100 cm ² of the sheet. -Extraction test: Dilute 15 g of the obtained polymer into an extraction bottle with 300 ml of distilled water. Put the extraction bottle in the sterilizer, 125 ℃
Leave for 60 minutes. After cooling, the extraction bottle is removed and the supernatant is measured for UV absorption and potassium permanganate consumption. At this time, a sample containing only distilled water containing the polymer is used as a standard. (UV absorption) Absorbance is measured at wavelengths of 220 nm and 241 nm, and if the difference from the reference value is 0.08 at 220 nm and 0.05 or more at 241 nm, it is marked with x. (Consumption amount of potassium permanganate) After adding potassium permanganate, titration is performed with sodium thiosulfate. Difference from the standard value is 1.00cc
In the above, it is set to x.・ Initial colorability: 100 parts by weight of the obtained polymer was mixed with 1 part by weight of tin lauryl acid, 0.5 part by weight of a cadmium stabilizer and 50 parts by weight of dioctyl phthalate, and the mixture was mixed with a two-roll mill at 160 ° C. for 5 minutes. After kneading, it was formed into a sheet having a thickness of 0.8 mm. Next, cut and stack this sheet,
Put in a 4cm × 4cm × 1.5cm (thickness) mold, 160 ℃, 65
A sample was prepared by heating and pressurizing at ~ 70 kgf / cm ² . This was visually observed and evaluated according to the following criteria. ⊚: Similar to Comparative Example 4. ◯: Yellowish color is stronger than in Comparative Example 4.

[Comparative Example 1] As a polymer scale adhesion preventive agent (II) of Comparative Example, 10 g of CI Direct Blue 1 was used.
CI Basic Blue 12 2g, deionized water 2000mL
And 17 g of phytic acid were added to prepare an aqueous solution to obtain a polymer scale anti-adhesion agent (II). This polymer scale deposition inhibitor (II) was applied to the inside of the polymerization vessel in the same manner as in Example 1, heated at 50 ° C. for 10 minutes and dried to form a coating film, and then the inside of the polymerization vessel was washed with water. Next, a vinyl chloride monomer was polymerized in the same manner as in Example 1 except that the polymerization initiators shown in Table 1 were used to obtain a polymer, which was then subjected to the test. The results are shown in Table 1.

[Comparative Example 2] Polymerization was carried out in the same manner as in Comparative Example 1 except that the polymerization initiators shown in Table 1 were used. The results are shown in Table 1.

[Comparative Example 3] Polymerization was carried out in the same manner as in Comparative Example 1 except that the polymerization initiator shown in Table 1 was used to obtain a polymer, which was then used in the test. The results are shown in Table 1. Two hours after the start of the polymerization, the jacket temperature reached the cooling water temperature of 25 ° C. In order to maintain the polymerization temperature at 55 ° C, it was necessary to lower the jacket temperature below 25 ° C, but the cooling capacity of the polymerization equipment used could not lower the jacket temperature further. For this,
The temperature of the aqueous suspension increased by 3 ° C to 58 ° C.

[0050]

[Table 1] The abbreviations for the polymerization initiators in Table 1 mean the following, respectively. BPD: t-butylperoxy neodecanoate (46 ° C) CPD: α-cumylperoxy neodecanoate (36 ° C) HDPD: 3-hydroxy-1,1-dimethylbutylperoxy neodecanoate (36) ℃)

[Examples 2 to 4, Comparative Examples 4 to 6]
A 2.1 m ³ stainless steel polymerization vessel was coated with the above polymer scale adhesion preventive agent (I) on the inner wall of the polymerization vessel, the stirring shaft, the stirring blade and other parts where the monomer comes into contact during the polymerization, and the mixture was heated at 40 ° C. for 15 minutes.
After heating and drying for a minute to form a coating film, the inside of the polymerization vessel was washed with water. Next, 930 kg of deionized water and 760 g of partially saponified polyvinyl alcohol were added as an aqueous solution and added. 50 mm inside
After evacuating to Hg, 630 kg of vinyl chloride monomer was charged, and while stirring, the polymerization initiators of the types and amounts shown in Tables 2 and 3 were injected with a pump, and at the same time the temperature was started to start the polymerization. . The polymerization reaction is carried out while maintaining the polymerization temperature at 51 ° C. When the internal pressure reaches 6.0 kg / cm ² G, the polymerization is stopped, unreacted monomers are recovered, and the obtained polymer is put into a slurry form. The sample was taken out, dehydrated and dried and subjected to the same test as in Example 1, and the results are also shown in Tables 2 and 3. In Comparative Example 4, the jacket temperature reached the cooling water temperature of 26 ° C. 3 hours and 30 minutes after the initiation of the polymerization, and the jacket temperature could not be further lowered by the cooling capacity of the polymerization apparatus. The temperature rose by 1.5 ° C.

[0052]

[Table 2]

[0053]

[Table 3] The abbreviations for the polymerization initiators in Tables 2 and 3 mean the following, respectively. BPD: t-butylperoxy neodecanoate (46 ° C) CPD: α-cumylperoxy neodecanoate (36 ° C) HDPD: 3-hydroxy-1,1-dimethylbutylperoxy neodecanoate (36) ℃)

[Comparative Examples 7 to 9] Polymerization was carried out in the same manner as in Example 2 except that the above scale preventive agent (II) was used in place of the scale preventive agent (I), and the results are shown in Table 4. Street initiator was used. Then, the same test as in Example 1 was performed, and the results are also shown in Table 4.

[0055]

[Table 4] The abbreviations for the polymerization initiators in Table 4 mean the following, respectively. BPD: t-butylperoxyneodecanoate (46 ° C) TPPD: 2,4,4-trimethylpentylperoxy-2-neodecanoate (36 ° C) HDPD: 3-hydroxy-1,1-dimethylbutylperoxyneo Decanoate (36 ℃)

[Examples 5 to 6 and Comparative Example 10] The internal volume was 2.1.
The above-mentioned polymer scale adhesion preventive agent (I) was applied to an inner wall of the polymerization vessel, a stirring shaft, a stirring blade, and other portions where the monomers come into contact with each other during the polymerization in a stainless steel polymerization vessel of m ^{3 and} the mixture was heated at 40 ° C. for 15 minutes After heating and drying to form a coating film, the inside of the polymerization vessel was washed with water. Next, 1030 kg of deionized water and 700 g of partially saponified polyvinyl alcohol were made into an aqueous solution and added. After degassing the inside of the container to 50 mmHg, charge 570 kg of vinyl chloride monomer,
While stirring, the polymerization initiators of the types and amounts shown in Table 5 were further injected with a pump, and at the same time the temperature was started to start the polymerization. The polymerization reaction was carried out while maintaining the polymerization temperature at 39 ° C. When the internal pressure reached 4.5 kg / cm ² G, the polymerization was stopped, unreacted monomers were recovered, and the obtained polymer was slurried. The sample was taken out, dehydrated and dried, and subjected to the subsequent tests. The results are also shown in Table 5.

[0057]

[Table 5] The abbreviations for the polymerization initiators in Table 5 mean the following, respectively. IBP: isobutyryl peroxide (33 ° C) BPD: t-butylperoxyneodecanoate (46 ° C) HDPD: 3-hydroxy-1,1-dimethylbutylperoxyneodecanoate (36 ° C)

[Comparative Examples 11 to 12] In each of Example 5 and Example 6, instead of the scale adhesion preventing agent (I),
Polymerization was carried out in the same manner as above except that the scale anti-sticking agent (II) was used, and the initiators shown in Table 6 were used.
Then, the same test as in Example 1 was performed, and the results are also shown in Table 6.

[0059]

[Table 6] The abbreviations in the polymerization initiators in Table 6 mean the following, respectively. IBP: isobutyryl peroxide (33 ° C) BPD: t-butylperoxyneodecanoate (46 ° C) HDPD: 3-hydroxy-1,1-dimethylbutylperoxyneodecanoate (36 ° C)

[0060]

EFFECTS OF THE INVENTION According to the production method of the present invention, a vinyl chloride polymer having good initial coloring properties and the like can be produced in a short polymerization time while suppressing the adhesion of polymer scale in the polymerization vessel. It can be manufactured. Therefore, the productivity is remarkably improved. In particular, the adhesion of polymer scale in the vicinity of the gas phase portion and the interface in the polymerization vessel, which was difficult in the past, is more reliably suppressed, and the frequency of polymer scale removal work in the polymerization vessel is drastically reduced. It enables continuous use over a long period of time.

Claims (2)

[Claims] 1. A vinyl chloride monomer or a mixture of vinyl-based monomers mainly composed of the vinyl chloride monomer is oil-soluble in an aqueous medium in a polymerization vessel having a coating film for preventing polymer scale adhesion on the inner wall surface of the polymerization vessel. In the method for producing a vinyl chloride polymer, which comprises suspension polymerization using a polymerization initiator, the coating film having the polymer scale adhesion preventing property is (a) the following general formula (1): [In the formula, R ^{1 s} may be the same or different,
_{H, -OH, -COOH, -SO 3} H, -NH 2, -Cl, -NO 2,
-COCH _3, -N (CH ₃₎ a ₂ and a group selected from the group consisting of alkyl group having 1 to 3 carbon atoms, X is an alkylene group having 1 to 5 carbon atoms, -N (CH ₃₎ −, −C (CH ₃ ) ₂
-, - CONH -, - P (= O) H-, -SO 2 -, - O -, - S-
And -Si (R) _2- (wherein R is an alkyl group having 1 to 10 carbon atoms). n is an integer of 1-2. ] A condensation product of a diphenyl compound having at least two amino groups represented by the following and a quinone compound, and (b) a water-soluble polymer compound,
The oil-soluble polymerization initiator is formed by applying an alkaline solution containing at least one selected from the group consisting of inorganic colloids and alkali metal silicates onto the inner wall surface and drying the solution. , (A) 10-hour half-life temperature of 0.1 mol / l benzene solution is 30-50
Chloride characterized by comprising (B) 3-hydroxy-1,1-dimethylbutylperoxyneodecanoate and an organic peroxide having no benzene ring or alkoxy group in its structure at ° C. A method for producing a vinyl polymer. 2. The component (A) of the oil-soluble polymerization initiator is represented by the following general formula (2): (In the formula, R ² and R ³ are each a substituted or unsubstituted n-alkyl group having 1 to 15 carbon atoms, sec-alkyl group, te
rt-alkyl group or cyclic alkyl group) and / or the following general formula (3): (In the formula, R ⁴ and R ⁵ are respectively a substituted or unsubstituted n-alkyl group having 1 to 20 carbon atoms, sec-alkyl group, te
The production method according to claim 1, which is a perester compound represented by (rt-alkyl group or cyclic alkyl group).