JP3319166B2 - Method for producing vinyl chloride polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a vinyl chloride polymer, and more particularly, to a method for suppressing the adhesion of polymer scale in a polymerization vessel during the production, and a high productivity. The present invention relates to a method for producing a vinyl chloride polymer capable of obtaining a high quality vinyl chloride polymer having a low polymerization degree having an average polymerization degree of 850 or less.

[0002]

2. Description of the Related Art A vinyl chloride polymer having a low degree of polymerization is usually a vinyl chloride monomer or a mixture of a vinyl monomer mainly composed of a vinyl chloride monomer (vinyl chloride monomer). ) In an aqueous medium by suspension polymerization using an oil-soluble polymerization initiator, a dispersion stabilizer and, if necessary, a chain transfer agent. The polymerization initiator used at this time depends on its type, such as heat generation pattern of polymerization reaction, polymerization time, productivity, adhesion of polymer scale at the time of polymerization, and further quality such as initial coloring property and thermal stability of the polymer. Significantly affects characteristics.

On the other hand, in recent years, the amount of a polymerization initiator added has been increased to shorten the polymerization time in order to improve the productivity of a vinyl chloride polymer.

In this case, as the amount of the polymerization initiator added increases, there are problems such as an influence on the quality of the polymer, particularly a decrease in the initial coloring property and an increase in the adhesion of the polymer scale in the polymerization vessel.

[0005] Further, in order to prevent adhesion of polymer scale in a polymerization vessel, conventionally, dyes, pigments, water-soluble polymer compounds, nitrites, nitrogen-containing aromatic compounds, hetero compounds, iodine compounds, pyrogallol derivatives, 2. Description of the Related Art A phenolic compound, an aromatic amine compound and the like are applied to the inner surface of a polymerization vessel as a polymer scale adhesion inhibitor.

[0006] However, the above-mentioned conventional scale inhibitor prevents the adhesion of the polymer scale in the polymerization vessel during the production of the vinyl chloride polymer having a low degree of polymerization, particularly the adhesion of the polymer scale in the gas phase and at the interface. It could not be effectively suppressed.

The present invention has been made in view of the above circumstances, and even if the polymerization time is shortened, it does not affect the quality of the obtained polymer such as initial coloring property, and the adhesion of the polymer scale in the polymerization vessel. An object of the present invention is to provide a method for producing a vinyl chloride-based polymer having a low degree of polymerization with high productivity while suppressing the production of the vinyl chloride-based polymer.

[0008]

The present inventors have conducted intensive studies to achieve the above object, and as a result, when polymerizing a vinyl chloride-based monomer, as a polymerization initiator,
(A) t-butyl peroxyneoheptanoate represented by the following general formula (1) and (B) a 0.1 mol / l benzene solution having a half-life of 10 hours at a temperature of 44 to 50:
By adding in combination with a perester-based peroxide at 55 ° C., a vinyl chloride-based polymer having a low degree of polymerization, which is not affected by quality such as initial coloring property, even when the polymerization time is shortened. It has been found that it can be obtained under high productivity and that the adhesion of the polymer scale can be prevented as much as possible.

[0009]

Embedded image (Wherein R ₁ and R ₂ are a methyl group or an ethyl group, R ₃
Is an ethyl group or a propyl group, and the total carbon number of R ₁ , R ₂ and R ₃ is 5. )

In this case, the above polymerization initiator is used, and (C) a diphenyl compound having at least two amino groups represented by the following general formula (2) and a quinone compound are used as a polymer scale adhesion inhibitor. And (D) a water-soluble polymer compound and / or (E)
It has been found that by applying a scale adhesion inhibitor comprising an alkaline solution containing an inorganic colloid and an alkali metal silicate to the inner wall of the polymerization vessel, polymer scale adhesion in the polymerization vessel is suppressed. It is what led to.

[0011]

Embedded image[However, in the formula, a plurality of R¹ Are the same but different
-H, -OH, -COOH, -SO_ThreeH, -N
H_Two, -Cl, -NO_Two, -COCH_Three, -OCH_Three, -N
(CH_Three)_TwoAnd an alkyl group having 1 to 3 carbon atoms
X is an alkyl having 1 to 5 carbon atoms.
Kylene group, -N (CH_Three)-, -C (CH_Three)_Two−, −C
ONH-, -P (= O) H-, -SO_Two−, − O −, −
S- and -Si (R)_Two-(Where R is 1 carbon atom
10 to 10 alkyl groups. Selected from the group consisting of
It is a divalent group. n is an integer of 1-2. ]

That is, the present invention relates to a method for producing a vinyl chloride monomer or a mixture of vinyl monomers containing the same as a main component, in suspension polymerization using an oil-soluble polymerization initiator in an aqueous medium. As the agent, (A) t- represented by the above general formula (1)
Butyl peroxyneoheptanoate and (B) 0.1
In addition to using a perester-based peroxide having a half-life of 10 hours in a mol / l benzene solution and a temperature of 44 to 55 ° C., (C) the above-mentioned general formula (2) A) a condensation product of a diphenyl compound having at least two amino groups and a quinone compound, and (D) a water-soluble polymer compound and / or (E) an inorganic colloid and an alkali metal silicate A method for producing a vinyl chloride polymer, which comprises applying a scale adhesion inhibitor comprising an alkaline solution containing at least one selected from the group consisting of:

Hereinafter, the present invention will be described in more detail. The oil-soluble polymerization initiator used in the method for producing a vinyl chloride polymer of the present invention comprises, as a component (A), a t-butyl par Oxyneoheptanoate is mentioned as an essential component, and the component (B) to be combined therewith is a 0.1 ml / l benzene solution,
It is a perester-based peroxide having a half-life of 10 hours at a temperature of 44 to 55 ° C, preferably 44 to 50 ° C.

[0014]

Embedded image (Wherein R ₁ and R ₂ are a methyl group or an ethyl group, R ₃
Is an ethyl group or a propyl group, and the total carbon number of R ₁ , R ₂ and R ₃ is 5. )

The component (B) has a half-life temperature as described above. In the case of a perester-based peroxide having the above-mentioned temperature of less than 44 ° C., a low-temperature polymerization usually carried out at a polymerization temperature of 58 ° C. or more is carried out. In the polymerization of the degree of polymerization of vinyl chloride, the calorific value per unit time in the initial stage of polymerization increases, and the heat removal ability by cooling is insufficient, and it is difficult to keep the polymerization temperature constant, which is not preferable. Further, in the case of a perester-based peroxide having the above-mentioned temperature exceeding 55 ° C., not only is it not economical due to an increase in the amount of the polymerization initiator added, but also the initial coloring property is deteriorated. It is not preferable in quality.

Specific examples of the component (B) include:
t-hexylperoxyneodecanoate (the temperature at which the half-life is 44.7 ° C., the same applies hereinafter), t-butylperoxyneodecanoate (46.5 ° C.), t-hexylperoxyneohexanoate (49.7 ° C), t-butyl peroxyneohexanoate (52.1 ° C), t-
Hexyl peroxyhyvalate (53.2 ° C.) and the like can be mentioned. Of these, t-hexylperoxyneodecanoate, t-butylperoxyneodecanoate and t-hexylperoxyneohexanoate are particularly preferred.

In the present invention, the component (A) and the component (B) are used in combination.
The weight ratio is (A) / (B) = 9/1 to 1/9, preferably 5/1 to 1/5, more preferably 2/1 to 1/2. The total amount of these additives is 0.01 to 0.12 parts by weight, preferably 0.03 to 0.1 parts by weight, based on 100 parts by weight of the total amount of the charged monomers. If the amount is too large, the amount of heat generated per unit time in the initial stage of polymerization increases, and accordingly, the heat generation capacity by cooling becomes insufficient, and it may be difficult to keep the polymerization temperature constant. Time cannot be reduced.

When these components (A) and (B) are added to a polymerization system as a polymerization initiator, they are diluted with a solvent or dispersed in water to form an emulsion or a suspension, and then added with water and / or suspension. It may be added together with the turbidity agent or after these preparations are completed, or may be press-fitted into the polymerization reactor by a pump after the preparation of the vinyl chloride monomer.

In the method for producing a vinyl chloride polymer of the present invention, a vinyl chloride monomer or a mixture of vinyl monomers containing the vinyl chloride monomer as a main component is subjected to suspension polymerization in an aqueous medium. The suspension polymerization can be performed by a known method except that a polymerization initiator composed of a combination of the above components (A) and (B) is used as the polymerization initiator.

In this case, as the vinyl chloride monomer used in the method of the present invention, in addition to vinyl chloride alone, a mixture of vinyl chloride as a main component and another monomer copolymerizable therewith (usually And at least 50% by weight of vinyl chloride). Examples of monomers copolymerized with vinyl chloride include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene and 1- Octene, 1-
Nonene, 1-decene, 1-undecene, 1-dodecene,
Α-olefins such as 1-tridecene and 1-tetradecene; acrylic acid such as acrylic acid, methyl acrylate and ethyl acrylate or esters thereof; methacrylic acid such as methacrylic acid and methyl methacrylate or esters thereof; maleic acid or esters thereof Vinyl esters such as vinyl acetate and vinyl propionate; lauryl vinyl ether;
Vinyl ethers such as isobutyl vinyl ether; maleic anhydride; acrylonitrile; styrene; vinylidene chloride; and other monomers copolymerizable with vinyl chloride. These may be used alone or in combination of two or more.

The suspension polymerization of these monomers in the aqueous medium according to the present invention can be carried out by a dispersing agent usually used in the polymerization of vinyl chloride monomers, for example, methyl cellulose, hydroxyethyl cellulose, Water-soluble cellulose ethers such as hydroxypropylcellulose and hydroxypropylmethylcellulose; water-soluble or oil-soluble partially saponified polyvinyl alcohol; acrylic acid polymers; water-soluble polymers such as gelatin; sorbitan monolaurate;
Oil-soluble emulsifiers such as sorbitan triolate, glycerin tristearate, and ethylene oxide propylene oxide block copolymer; water-soluble emulsifiers such as polyoxyethylene sorbitan monolaurate, polyoxyethylene glycerin oleate, and sodium laurate.
Species or a combination of two or more can be used.

The polymerization system may further include, if necessary, a polymerization regulator, a chain transfer agent, a pH regulator, a gelling improver, an antistatic agent, a crosslinking agent, and the like, which are appropriately used for vinyl chloride polymerization. It is also optional to add stabilizers, fillers, antioxidants, buffers, scale inhibitors and the like.

The other conditions for this polymerization, the method of charging the aqueous medium, the vinyl chloride-based monomer, the dispersing aid, etc. to the polymerization vessel, the charging ratio, and the like may be the same as those in the conventional method.

The polymerization temperature is not particularly limited, but from the viewpoint of obtaining a low polymerization degree vinyl chloride copolymer having an average polymerization degree of 850 or less, it is recommended to be 58 ° C. or more, more preferably 59 to 68 ° C. .

In the present invention, the above polymerization initiator is used, and (C)
A condensation product of a diphenyl compound (C-1) having at least two amino groups represented by the following general formula (2) and a quinone compound (C-2), and (D) a water-soluble polymer compound and / or Or (E) using a scale adhesion inhibitor composed of an alkaline solution containing at least one selected from the group consisting of an inorganic colloid and an alkali metal silicate, and applying the scale adhesion inhibitor in a polymerization vessel. do it,
The above suspension polymerization is performed. Thus, by using the polymerization initiator and the scale adhesion inhibitor in combination, the adhesion of the polymer scale in the polymerization vessel can be surely prevented.

[0026]

Embedded image[However, in the formula, a plurality of R¹ Are the same but different
-H, -OH, -COOH, -SO_ThreeH, -N
H_Two, -Cl, -NO_Two, -COCH_Three, -OCH_Three, -N
(CH_Three)_TwoAnd an alkyl group having 1 to 3 carbon atoms
X is an alkyl having 1 to 5 carbon atoms.
Kylene group, -N (CH_Three)-, -C (CH_Three)_Two−, −C
ONH-, -P (= O) H-, -SO_Two−, − O −, −
S- and -Si (R)_Two-(Where R is 1 carbon atom
10 to 10 alkyl groups. Selected from the group consisting of
It is a divalent group. n is an integer of 1-2. ]

Here, the diphenyl compound (C-1)
Specifically, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl ether,
4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylsulfone, 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 exemplified.

Of these, preferred are 4,4'-
Diaminodiphenyl sulfone, 4,4'-diaminobenzanilide, 4,4'-diaminodiphenyl ether and 4,4'-diaminodiphenylmethane.

As the component (C-1), one type may be used alone, or two or more types may be used in combination.

On the other hand, as the quinone compound (C-2),
For example, there are benzoquinone compounds represented by the following general formulas (3) and (4), and naphthoquinone compounds represented by the following general formulas (5) and (6).

[0031]

Embedded image(However, in each formula, a plurality of R^Two Are the same but different
-H, -NH_Two, -Cl, -Br, -O
H, -NO_Two, -COCH_Three, -OCH_Three, -N (CH_Three)
_TwoAnd an alkyl group having 1 to 3 carbon atoms.
It is a group that is exposed. In each formula, a plurality of R^Three Are the same as each other
May be one or different, and may be -H, -Cl, -Br,-
OH, -COCH_Three, -OCH_Three, -CH_Three, -COOH
And -SO_ThreeAnd a group selected from the group consisting of H. )

Specific examples of the benzoquinone compounds represented by the general formulas (3) and (4) include o-, m-, and p-benzoquinone, hydroxy-p-benzoquinone, chloro-p-benzoquinone, and bromo- p-benzoquinone,
Examples include duloquinone and chloranil. Specific examples of the naphthoquinone compounds represented by the general formulas (5) and (6) include 6-methyl-1,4-naphthoquinone,
-Methyl-1,4-naphthoquinone, Lawson, juglone, plumbagin, α-naphthoquinone, β-naphthoquinone and the like.

Among these quinone compounds, those which are preferable as the component (C-2) in the present invention include o- and p-
-Benzoquinone, α-naphthoquinone, β-naphthoquinone and Lawson.

The quinone compound (C-2) may be used alone or in combination of two or more.

The polymer scale adhesion inhibitor of the present invention contains a condensation product obtained by condensing the component (C-1) with the component (C-2). Hereinafter, the condensation reaction will be described in more detail.

The above condensation product is prepared by subjecting the components (C-1) and (C-2) to a suitable solvent in the presence of a catalyst if necessary, usually at room temperature to 200 ° C. for 0.5 to 100 hours, preferably Is produced by reacting at room temperature to 150 ° C. for 3 to 30 hours.

Since component (C-2) also acts as a condensation catalyst, it is usually unnecessary to add another condensation catalyst. However, when another condensation catalyst is added, usable condensation catalysts include: Elemental or molecular elemental halogens such as iodine, bromine, chlorine and fluorine; oxygen acids and oxyacid salts of halogens such as iodic acid, periodic acid, potassium periodate and sodium perchlorate; hydrogen peroxide, peroxide Inorganic peroxides such as sodium, potassium persulfate and ammonium persulfate; organic peroxides such as peracetic acid, benzoyl peroxide, cumene hydroperoxide, perbenzoic acid, p-menthane hydroperoxide; ferrous chloride, chloride Chlorides and sulfates of metals selected from iron and copper such as ferric, copper sulfate and cuprous chloride; α, α′-azobisisobutyronitrile, α, α′-azo Azo compounds such as bis-2,4-dimethylvaleronitrile; nitrobenzene, o-, m
-And p-oxynitrobenzene, o-, m- and p-
Nitroanisole, o-, m- and p-chloronitrobenzene, o-, m- and p-nitrobenzoic acid, o-, m
And nitro aromatic compounds such as p-nitrobenzenesulfonic acid and the like.

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 having miscibility 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; aprotic solvents such as dimethylformamide, dimethyl sulfoxide and acetonitrile; and the like, among which alcohols are particularly preferable. It is also possible to use a mixed solvent of water and an organic solvent miscible with water.

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

In conducting the condensation reaction, the component (C-1) and the component (C-1)
The proportion of the component (C-2) depends on the components (C-1) and (C-
2) Depending on the type of the component and the solvent, the reaction temperature, the reaction time, and the like, usually, (C-
2) The component is preferably used in an amount of 0.01 to 10 parts by weight,
In particular, it is preferably 0.1 to 5 parts by weight. (C-2)
If the amount of the component is too large or too small, the effect of the obtained condensation product on preventing the adhesion of polymer scale is reduced.

The polymer scale adhesion inhibitor used in the present invention comprises an alkaline liquid containing a condensation product of the above components (C-1) and (C-2). The concentration of the product in the alkaline liquid is not particularly limited as long as the total coating amount described below can be obtained, but is usually 0.001.
-5% by weight, preferably 0.01-1% by weight. In order to further enhance the effect of preventing the adhesion of the polymer scale, the scale adhesion inhibitor is selected from the group consisting of (D) a water-soluble polymer compound and / or (E) an inorganic colloid and a silicate of an alkali metal. At least one of them is added. More preferably, (D) and (E) are added in combination. These additives (D) and (E) probably interact with the condensation product to increase the hydrophilicity of the coated surface ((D) water-soluble polymer compound) or to reduce the polymer scale adhesion inhibitor. It is presumed to have the effect of increasing the adhesion to the inner wall of the polymerization vessel ((E) at least one selected from the group consisting of inorganic colloids and alkali metal silicates).

The water-soluble polymer compound (D) includes amphoteric polymer compounds such as gelatin and casein; anionic polymer compounds such as polyacrylic acid, polystyrene sulfonic acid, carboxymethyl cellulose, and alginic acid;
Examples include cationic nitrogen-containing polymer compounds such as polyvinylpyrrolidone and polyacrylamide; and hydroxyl group-containing polymer compounds such as polyvinyl alcohol, hydroxyethylcellulose, hydroxypropylcellulose, and pectin.

Preferred among the above-mentioned water-soluble polymer compounds are gelatin, casein, polyacrylic acid, carboxymethylcellulose, polyvinylpyrrolidone and pectin.

The water-soluble polymer compound (D) can be used alone or in combination of two or more.

The amount of the water-soluble compound (D) to be added to the polymer scale adhesion inhibitor is usually 0.01 to 10 parts by weight per 1 part by weight of the condensation product of the component (C). Preferably it is 0.05 to 2 parts by weight.

On the other hand, the inorganic colloid of the component (E)
For example, it is a particle colloid produced by a dispersion method using water as a dispersion medium or an agglomeration method.
５００500 nm.

Specific examples of the inorganic colloid include colloids of oxides and hydroxides of metals selected from aluminum, thorium, titanium, zirconium, antimony, tin, iron, etc., tungstate, vanadium pentoxide, gold and Silver colloid, silver iodide sol, colloid of selenium, sulfur, silica and the like are exemplified. Preferred among these are colloids of oxides and hydroxides of metals selected from aluminum, titanium, zirconium, tin and iron, and colloidal silica.

The component (E) contains alkali metal cations.
For example, lithium, sodium, potassium
Alkali metal metasilicate (M _TwoSiO_Three),
Orthosilicate (M_FourSiO_Four), Disilicate (M _TwoSi_Two
O_Three), Trisilicate (M_ThreeSi_ThreeO₇), Sesquisilicic acid (M
_FourSi_ThreeO_Ten) Etc. (where M is lithium, sodium
And alkali metals such as potassium. ) And water
Lath and the like.

The above component (E) can be used alone or in combination of two or more. The amount of the component (E) added to the polymer scale adhesion inhibitor is usually 0.01 to 10 parts by weight, preferably 0.05 to 10 parts by weight, per part by weight of the condensation product of the component (C). 5 parts by weight.

When the above components (D) and (E) are used in combination, 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 is used. Is preferred. When used in combination of a water-soluble polymer compound and an inorganic colloid, it is preferable to use 5 to 3000 parts by weight of an inorganic colloid per 100 parts by weight of a water-soluble polymer compound, and it is particularly preferable to use 50 to 1000 parts by weight. preferable. on the other hand,
When used in combination of a water-soluble polymer compound and an alkali metal silicate, it is preferable to use 5 to 3000 parts by weight of an alkali metal silicate per 100 parts by weight of a water-soluble polymer compound. It is preferable to use 50 to 1000 parts by weight.

The polymer scale adhesion inhibitor used in the present invention can be obtained by adding the following solvent as necessary to the condensation product-containing liquid obtained by subjecting the components (C-1) and (C-2) to a condensation reaction. , By adjusting the pH to alkaline. Further, the polymer scale adhesion inhibitor, after the condensation product-containing liquid is poured into cold water to precipitate the condensation product,
The precipitate may be filtered and dried, and the following solvent may be added thereto to adjust the pH to be alkaline. It can be obtained by adding the above-mentioned component (D) and / or component (E) thereto.

It is necessary that the scale adhesion inhibitor used in the present invention is made alkaline, and by making it alkaline, the solubility of the condensation product of the components (C) and (D) in the solvent is improved. Accordingly, since the polymer scale adhesion inhibitor becomes a uniform solution, the polymer scale adhesion prevention effect can be improved when applied to the inner wall surface of the polymerization vessel or the like. In this case, the pH of the polymer scale adhesion inhibitor is preferably from 7.5 to 13.5, and in particular, p
H8.0 to 12.5 is preferred. Alkaline compounds used for pH adjustment include LiOH, NaO
Alkali metal compounds such as H, KOH, Na ₂ CO ₃ , Na ₂ HPO ₄ and NH ₄ OH, and ammonia compounds, and
Examples thereof include organic amine compounds such as ethylenediamine, monoethanolamine, diethanolamine, and triethanolamine. The solvent used for preparing the polymer scale adhesion inhibitor is water; methanol, ethanol, propanol, butanol, 2-butanol, 2-
Methyl-1-propanol, 2-methyl-2-propanol, 3-methyl-1-butanol, 2-methyl-2-
Alcoholic solvents such as butanol and 2-pentanol;
Ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as methyl formate, ethyl formate, methyl acetate, ethyl acetate and methyl acetoacetate; ether solvents such as 4-methyldioxolane and ethiselenglycol diethyl ether; Furans; aprotic solvents such as dimethylformamide, dimethylsulfoxide, and acetonitrile; These solvents can be used singly or as a mixture of two or more solvents.

Preferred among the above-mentioned solvents are water and a mixed solvent of water and an organic solvent miscible with water.
Among the above organic solvents, examples of the organic solvent having miscibility with water 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 exemplified. When using a water-miscible organic solvent and a water-miscible solvent, the content of the organic solvent should be such that there is no danger of ignition, explosion, etc., and there is no problem in handling safety such as toxicity. It is preferable that the content of the organic solvent is 50% by weight or less, specifically, 30% by weight or less.

In order to form a coating film on the inner wall of the polymerization vessel using the above-mentioned polymer scale adhesion inhibitor, first, the inhibitor is applied to the inner wall of the polymerization vessel, and then, for example, from room temperature to 100 ° C.
After sufficiently drying in the temperature range up to the above, a method of further washing with water can be adopted as needed.

Further, the above-mentioned polymer scale adhesion inhibitor comprises:
It is preferable to apply the coating not only on the inner wall surface of the polymerization vessel but also on other portions where the monomer comes into contact 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 adhesion preventive agent may be located at a site where polymer scale is likely to adhere, for example, at a site other than the site where the monomer comes into contact during polymerization, for example, the recovery of unreacted monomer. On the inner surface of the system equipment and piping,
It is better to form the coating film. 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 for applying the polymer scale adhesion inhibitor to the inner wall surface of the polymerization vessel is not particularly limited. For example, brush coating, spray coating, a method of filling the polymerization vessel with the polymer scale adhesion inhibitor, and then extracting the polymer scale. And others, JP-A-57-61001, JP-A-55-36288,
JP-B-56-501116, 56-501117
And the automatic coating method described in JP-A No. 59-11303.

The method of drying the wet surface by applying the polymer scale adhesion inhibitor is not limited, and for example, the following method can be used. That is, after the application of the polymer scale anti-adhesion agent, a method of applying warm air appropriately heated to the application surface, or the inner wall surface of the polymerization vessel and the other surface to which the polymer scale anti-adhesion agent is to be applied is previously 30 to 30, for example. It is possible to adopt a method in which the polymer scale is heated to 80 ° C. and the polymer scale adhesion preventing agent is directly applied to the heated surface. And
After drying the coated surface, the coated surface is washed with water as needed.

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

The above-mentioned coating operation may be performed for every one to ten or more batches of polymerization. Since the formed coating film has high durability and the action of preventing adhesion of the polymer scale is maintained, it is not always necessary to perform the coating for each batch of polymerization, so that the productivity is improved.

[0061]

According to the method for producing a vinyl chloride polymer of the present invention, the influence on the quality of the polymer due to the shortening of the polymerization time in the production of the vinyl chloride polymer having a low degree of polymerization has been hitherto. This solves the problem that the adhesion of polymer scale in the polymerization vessel cannot be effectively suppressed, and achieves high quality and low polymerization degree vinyl chloride based on high productivity even if the polymerization time is shortened. Coalescence can be obtained, and adhesion of the polymer scale in the polymerization vessel, in particular, adhesion of the polymer scale in the gas phase and at the interface can be effectively prevented.
Further, in particular, the above-mentioned polymer scale adhesion inhibitor is used in combination with the above-mentioned polymerization initiator, and this is applied to the inner wall of the polymerization vessel,
Due to the coating film formed by drying, adhesion of the polymer scale at the interface portion in the polymerization vessel is more reliably suppressed, and the frequency of cleaning the polymer scale in the polymerization vessel is also drastically reduced, so that long-term continuous operation is possible. It becomes possible.

[0062]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Example 1 First, the polymer scale adhesion inhibitor (I) of the present invention was produced as follows. In a 2 liter internal volume reactor equipped with a reflux condenser, methanol 8 was added.
00 g and dimethylformamide (DMF) 100 g
And 40 g of 4,4'-diaminodiphenylsulfone were charged and stirred at room temperature to dissolve 4,4'-diaminodiphenylsulfone in methanol / DMF.

To the methanol / DMF solution thus obtained, 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 dropped into water. The deposited precipitate was separated by filtration and dried to obtain a condensation product (C).

The condensation product (C), gelatin as the water-soluble polymer compound (D), colloidal silica as the inorganic colloid (E) [Snowtex CXS-9 (trade name, manufactured by Nissan Chemical Industries, Ltd. Colloid particle size 5nm ~ 7
(C) / (D) / (E) = 1/1/1 (weight ratio), using water / methanol = 7/3 (weight ratio) as a solvent, (C), (D) , (E) was adjusted to a total concentration of 0.5%, and the solution was adjusted to pH =
11.0 to adjust the polymer scale adhesion inhibitor (I)
I got

The internal volume is 2.1 m^Three Stainless steel polymerization vessel
Polymer scale adhesion inhibitor prepared as described above
(I) is being polymerized on the inner wall of the polymerization vessel, stirring shaft, stirring blade, etc.
And apply at 40 ° C for 15 minutes.
After the film was formed by heating and drying, the inside of the polymerization vessel was washed with water.

Next, an aqueous solution of 880 g of deionized water, 210 g of partially saponified polyvinyl alcohol and 140 g of hydroxypropylmethylcellulose was charged into the polymerization vessel. After degassing the vessel to 50 mmHg, 700 kg of vinyl chloride monomer was charged, and further stirred,
At the same time as the polymerization initiator shown in Table 1 was press-fitted with a pump, the temperature was raised and polymerization was started.

The polymerization reaction was carried out while maintaining the polymerization temperature at 63 ° C., and when the internal pressure of the polymerization vessel dropped to 7.5 kg / cm ² G, the polymerization was stopped, and the unreacted monomer was recovered. The polymer was taken out of the vessel in the form of a slurry, dehydrated, and dried to obtain a polymer.

Comparative Example 1 As a polymer scale adhesion inhibitor (II) of Comparative Example, C.I. I. Direct Blue 1
(Trade name, manufactured by Aldrich) 10 g, C.I. I. 2 g of Basic Blue 12 (trade name, manufactured by Aldrich) is dissolved in 2000 ml of ion-exchanged water, and 17 g of phytic acid is further dissolved.
Was added to obtain a polymer scale adhesion inhibitor (II).

This polymer scale adhesion inhibitor (II) was applied in a polymerization vessel in the same manner as in Example 1, heated and dried at 50 ° C. for 10 minutes 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 initiator was changed as shown in Table 1, to obtain a polymer.

Comparative Example 2 Polymerization was carried out in the same manner as in Comparative Example 1 except that the polymerization initiator was changed as shown in Table 1 to obtain a polymer.

Comparative Example 3 Polymerization was carried out in the same manner as in Example 1 except that the polymerization initiator was changed as shown in Table 1, to obtain a polymer.

Example 2 A coating film of the polymer scale adhesion inhibitor (I) was formed in the polymerization vessel in the same manner as in Example 1, and the inside of the polymerization vessel was washed with water. An aqueous solution of 303 g of functionalized polyvinyl alcohol and 240 g of hydroxypropylmethylcellulose was charged into the polymerization vessel. After degassing the vessel to 50mmHg,
730 kg of a vinyl chloride monomer was charged, and the polymerization initiator shown in Table 2 was injected with a pump while stirring, and at the same time, the temperature was raised and polymerization was started. One hour after the start of the temperature increase, 204 g of 2-mercaptoethanol as a polymerization degree adjusting agent was injected.

The polymerization reaction was carried out while maintaining the polymerization temperature at 62 ° C., and when the internal pressure of the polymerization reactor dropped to 7.2 kg / cm ² G, the polymerization was stopped, and the unreacted monomers were recovered. The polymer was taken out of the vessel in the form of a slurry, dehydrated, and dried to obtain a polymer.

Example 3 Polymerization was carried out in the same manner as in Example 2 except that the polymerization initiator was changed as shown in Table 2, to obtain a polymer.

[Comparative Examples 4 and 5] In the same manner as in Comparative Example 1, except that the polymer scale adhesion inhibitor (I) was used as the polymer scale adhesion inhibitor (II), a coating film was formed in the polymerization vessel. After the formation, the inside of the vessel was washed with water, and polymerization was carried out in the same manner as in Example 2 except that the polymer initiator was changed as shown in Table 2, to obtain a polymer.

The quality of each polymer obtained as described above was evaluated by the following method, and the results are shown in Tables 1 and 2. <Average degree of polymerization> Measured according to JIS K-6721. <Bulk specific gravity> It was measured according to JIS K-6721. <Particle size distribution># 60 according to JIS Z-8801,
The mixture was sieved using # 100 and # 200 sieves, and the residual amount and the passing amount (% by weight) were measured. <Initial Colorability> 1.0 part by weight of tin laurate, 0.5 part by weight of a cadmium-based stabilizer and 50 parts by weight of a plasticizer DOP are mixed with 100 parts by weight of a vinyl chloride polymer, and the mixture is heated at 160 ° C. using a 6-inch roll. After kneading for 5 minutes, thickness 0.8mm
Was formed. Next, this sheet was cut and layered, put in a 4 cm × 4 cm × 1.5 cm formwork,
It heated and press-molded at 65-70 kgf / cm < ² > C, and the measurement sample was produced. JIS Z-873 for this measurement sample was measured using a photoelectric colorimeter (manufactured by Nippon Denshoku Industries Co., Ltd.).
The L value, a value, and b value in the color difference formula of the hunter described in No. 0 were measured and evaluated. <Polymer scale adhesion> After repeating 10 batches of polymerization by each production method, the inside of each polymerization vessel was observed to evaluate the degree of adhesion of the polymer scale.

[0079]

[Table 1]

[0080]

[Table 2] * Polymerization initiator BPN _P: t-butyl peroxy heptanoate (half-life temperature 50 ℃) BPD: t- butyl peroxyneodecanoate (half-life temperature 46.5 ℃) HPV: t- hexylperoxy Pivalate (half-life temperature 53.2 ° C) THP: 3,5,5-trimethylhexanoyl peroxide (half-life temperature 59.5 ° C)

From the results shown in Tables 1 and 2, the relatively low polymerization degree of the vinyl chloride polymer obtained by the present invention adversely affects the bulk density, the particle size distribution and the quality of the initial coloring even when the polymerization time is shortened. And that the production method of the present invention suppresses adhesion of the polymer scale in the gas phase part and the liquid phase part in the polymerization vessel.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-316214 (JP, A) JP-A-7-82303 (JP, A) JP-A-6-199905 (JP, A) 18852 (JP, B1) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08F 2/00-2/60 C08F 4/34

Claims (2)

(57) [Claims] 1. A vinyl chloride monomer or a main component thereof
Initiation of oil-soluble polymerization of vinyl monomer mixture in aqueous medium
When performing suspension polymerization using an agent, as the polymerization initiator
(A) The following general formula (1)(Where R₁And R_TwoIs a methyl or ethyl group, R_Three
Is an ethyl group or a propyl group,₁, R_Two, R_Threeof
The total carbon number is 5. T-butylperoxide represented by)
Xineoheptanoate and (B) 0.1 mol / l
The temperature at which the half-life in the solution is 10 hours is 4
Use a perester peroxide that is 4 to 55 ° C
In addition, as a polymer scale adhesion inhibitor, (C) below
General formula (2)[However, in the formula, a plurality of R¹ Are the same but different
-H, -OH, -COOH, -SO_ThreeH, -N
H_Two, -Cl, -NO_Two, -COCH_Three, -OCH_Three, -N
(CH_Three)_TwoAnd an alkyl group having 1 to 3 carbon atoms
X is an alkyl having 1 to 5 carbon atoms.
Kylene group, -N (CH_Three)-, -C (CH_Three)_Two−, −C
ONH-, -P (= O) H-, -SO_Two−, − O −, −
S- and -Si (R)_Two-(Where R is 1 carbon atom
10 to 10 alkyl groups. Selected from the group consisting of
It is a divalent group. n is an integer of 1-2. ]
Diphenyl compound having at least two amino groups
And a condensation product of a quinone compound and (D) water-soluble
High molecular compound and / or (E) inorganic colloid and alka
At least one selected from the group consisting of silicates of lithium metals
Prevention of scale adhesion consisting of alkaline solution containing seed
Vinyl chloride characterized by applying a blocking agent in a polymerization vessel
A method for producing a polymer. 2. The method for producing a vinyl chloride polymer according to claim 1, wherein the polymerization temperature is 58 ° C. or higher.