KR20150037250A - Method of preparing vinyl chloride-based polymers by suspension polymerization system - Google Patents

Abstract

The present invention relates to a process for producing a suspension polymerized vinyl chloride polymer. According to the present invention, scale adhesion can be suppressed by introducing a new scale inhibitor, heat recovery efficiency can be increased, reaction- It is possible to provide an effect of preventing recondensation and improving the quality of protrusions.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for producing a suspension polymerized vinyl chloride polymer,

The present invention relates to a process for producing a suspension polymerized vinyl chloride polymer, and more particularly, to a process for producing a vinyl chloride polymer by suspension polymerization, which comprises introducing a new scale inhibitor to increase the heat- And a process for producing the vinyl chloride polymer.

The vinyl chloride polymer has been used in various fields because of its excellent economical efficiency, easy processing, and simple polymerization process. The vinyl chloride polymer refers to an interpolymer obtained by polymerizing a mixture of vinyl chloride or a monomer copolymerizable with vinyl chloride.

By controlling the polymerization temperature in a simple manner, polymers having different polymerization degrees can be produced, and they can be applied to hard and soft fields because they have different characteristics depending on their degree of polymerization.

Firstly, it is used for pipes, films, window frames and the like in the hard field, and is used for electric wire coating, wrap film and sheet in the soft field.

The polymerization method of the vinyl chloride polymer is mainly produced by the emulsion polymerization method and the suspension polymerization method. In the suspension polymerization method, polymerization is carried out using water, a suspension stabilizer, a vinyl chloride monomer and an initiator, It can be processed immediately after drying. The polymerized vinyl chloride polymer is excellent in electrical insulation properties and excellent in chemical resistance, and is widely used as a chemical container.

The emulsion polymerization is carried out by using water, an emulsifier, a vinyl chloride monomer, and an initiator. The vinyl chloride polymer produced by the emulsion polymerization method has excellent viscosity stability, good flow properties during product processing, It is often used as flooring.

Usually, the suspension polymerization of the vinyl chloride monomer is carried out batchwise, the vinyl chloride monomer and the initiator additive are added, and the temperature is raised to the polymerization temperature to initiate the polymerization reaction. When heat is generated by the exothermic reaction, the vinyl chloride polymer is polymerized by flowing cooling water through the jacket to maintain the polymerization temperature.

In order to obtain a high efficiency and a production increase effect in the production of the vinyl chloride polymer through the suspension polymerization, the domestic and foreign companies are moving to a large-scale reaction technology of 100 m ³ or more. Large reactors are excellent in increasing productivity, but they are accompanied by various problems.

Particularly, as the reactor becomes larger, the jacket occupies a relatively small area, so it is necessary to be very careful in setting the heat-separating ability. One of the reasons for lowering the heat removal efficiency is the scale generated during the reaction.

In general vinyl chloride polymerization, the scale generated on the inner wall of the reactor affects the thermal stability, the conversion rate, the reactor cleaning time, the thermal efficiency and the like, thereby causing deterioration of physical properties and productivity. That is, when scale is generated on the inner wall of the reactor, the heat transfer is not performed well and the reaction time becomes long. In addition, in severe cases, heat removal is not performed well, resulting in abnormally increased reaction pressure during the reaction, which may lead to explosion of the reactor. In addition, as the reactor becomes larger, the ability to suppress the scale caused by the deterioration of the jacket heat-dissipating ability becomes an important issue.

Also, as the reactor using the reflux condenser is increased, the cleaning state of the reflux condenser can be a very important quality deviation factor. Since the reflux condenser has a large surface area, its surface property is very important, and when scale is generated, there is a drastic decrease in the heat removal efficiency. In addition, the scale built up in the reflux condenser is difficult to clean and will adversely affect the quality of the next batch of projections.

In order to solve such a problem, U.S. Patent No. 5,780,104 discloses a technique for inhibiting scale formation on the inner wall of a reactor by dissolving a phenolic compound in a basic aqueous solution and coating the inner wall of the reactor. In U.S. Patent No. 4,451,625, A method of coating a catalyst on a reactor is disclosed.

However, since most of the materials are used in a basic aqueous solution, the coating film is destroyed by HCl which is generated as a side reaction during polymerization, and since the color is very dark black, the whiteness of the vinyl chloride polymer Which is the cause of the problem.

In addition, Japanese Unexamined Patent Publication No. 1998-120708 proposes a technique for suppressing scale by adding a saturated higher fatty acid having 12 to 31 carbon atoms and a saturated higher alcohol having 15 to 31 carbon atoms at the start of the polymerization reaction. However, To 3 parts by weight, which raises the manufacturing cost. Also, in Japanese Laid-Open Patent Application No. 1998-265511, a method of lowering the coagulation rate of the inner wall of the reactor by changing the agitation force according to the polymerization rate has been described, but the scale improvement effect is insignificant.

In order to solve the problems of the prior art described above, the present inventors have found that by controlling the scale inside the reactor and the inside of the reflux condenser, the fish eye characteristics are improved and the jacket heating effect is enhanced, In studying various solutions for the production method of the vinyl chloride polymer, when the specific trivalent metal sulfate is coated on the inner wall of the reactor or added during the polymerization, scaling is suppressed in the reactor to improve the fish eye characteristics, And further, it is possible to improve the conversion efficiency and the productivity by increasing the thermal efficiency and shortening the cleaning time. Thus, the present invention has been accomplished.

That is, an object of the present invention is to provide a method for producing a suspension vinyl chloride polymer capable of reducing the scale of the reactor inner wall and the reflux condenser.

It is also an object of the present invention to provide a method of manufacturing a reactor, which comprises coating or injecting an anti-scale agent on the inner wall and the inner wall of the reflux condenser, thereby suppressing scale formation on the inner wall of the reactor, improving the quality of the fish eye and improving thermal stability, The present invention provides a method for producing a suspension-polymerized vinyl chloride polymer which is excellent in quality and productivity.

In order to achieve the above object, according to the present invention,

A suspension polymerization system comprising a suspension stabilizer, a polymerization initiator and a vinyl chloride monomer, wherein the polymerization system comprises a trivalent metal sulfate, and a suspension polymerization system characterized by using the suspension polymerization system Respectively. ≪ / RTI >

According to the process for producing a suspension polymerization-type vinyl chloride polymer of the present invention, the scale adhesion can be suppressed by introducing the new scale inhibitor, the heat removal efficiency can be raised, the reactor cleaning time can be shortened, The effect of preventing the polymerization and improving the quality of the protrusion can be provided.

Hereinafter, the present invention will be described in more detail.

First, the present invention is characterized in that in the suspension polymerization system of a suspension stabilizer, a polymerization initiator and a vinyl chloride monomer, the polymerization system includes a trivalent metal sulfate.

The term " trivalent metal sulfate " used in the present invention is acidic in an aqueous solution state, unless otherwise specified, and specifically excludes sulfites / sulfates / persulfates of alkali metals and includes sulfates containing trivalent metals Quot;

As a specific example, the trivalent metal sulfate is characterized by being contained as an inner coating of a suspension polymerization reactor.

As another example, the trivalent metal sulfate may be included, for example, as an internal coating of a reflux condenser provided in a suspension polymerization reactor.

As another example, the trivalent metal sulfates are characterized in that they are included in the reactor during polymerization.

As a specific example, the trivalent metal sulfate may be contained at a conversion rate of 30 to 80%, or 30 to 60% of the polymerization. For reference, it is possible to lower the interfacial stability of water and vinyl chloride monomer by changing the pH and to change the particle diameter, the plasticizer absorption rate and the fine particle content when the polymerization conversion rate is 30% or less, Since the scale is generated after the scale is turned on, the input effect can not be obtained.

In addition, the trivalent metal sulfate may be continuously charged, intermittently charged or batch charged.

As concrete examples of application, when the vinyl chloride monomer is polymerized, the polymerization is started by coating the inner wall of the reactor and the reflux condenser with the trivalent metal sulfate in the step of washing the reactor before the addition of the raw material, or the suspension stabilizer, the polymerization initiator and the vinyl chloride monomer And the scale generated at the inner wall of the reactor can be suppressed by injecting the trivalent metal sulfate continuously or intermittently at the time of polymerization conversion of 30 to 80% at the time of occurrence of scale during the polymerization.

The trivalent metal sulfate may be 0.005 to 0.1 part by weight or 0.005 to 0.06 part by weight per 100 parts by weight of the vinyl chloride monomer used in the suspension polymerization. Below the lower limit, the effect of preventing scale is insignificant and the desired purpose can not be achieved. When the upper limit is exceeded, the pH of the vinyl chloride polymerized water is changed. As a result, the physical properties and particle size of the final resin may be changed, .

The trivalent metal sulfate may be, for example, a sulfate including at least one trivalent metal selected from Ga3 +, Fe3 +, Al3 +, In3 +, Ru3 +, Sc3 + and Y3 +. The trivalent metal sulfate acts not only as a metal corrosion inhibitor but also as a water treatment agent for capturing metal ions present in the water. Therefore, metal ions generated by corrosion of the reactor wall surface or metal ions which are contained in monomers and adversely affect physical properties To form a complex, thereby suppressing scale generation and having a good effect on thermal stability.

Examples of the suspension stabilizer include a vinyl alcohol resin having a hydration degree of 30 to 90% by weight and a viscosity of 4 to 5% aqueous solution at room temperature of 10 to 60 cps, a propyl methacrylate resin having a methoxy group content of 15 to 40% By weight and a viscosity of 2% aqueous solution measured at room temperature is 10 to 20,000 cps, and an unsaturated organic acid.

The content of the suspension stabilizer may be, for example, 0.03 to 5 parts by weight based on 100 parts by weight of the vinyl chloride monomer used in the suspension polymerization.

The content of the polymerization initiator is, for example, 0.02 to 0.2 parts by weight per 100 parts by weight of the vinyl chloride monomer used in the suspension polymerization.

There can be provided a method for producing a vinyl chloride polymer by using the suspension polymerization system described above.

Specifically, the vinyl chloride monomer may be such that the polymerization water is introduced, and the dispersant and the initiator are charged and then charged.

The vinyl chloride monomer may be used in combination with a copolymerizable monomer. Examples thereof include olefins such as ethylene and propylene, vinyl esters such as vinyl acetate and vinyl propionate, unsaturated nitriles such as acrylonitrile, vinyl methyl ether, vinyl ethyl ether , Unsaturated fatty acids such as acrylic acid, methacrylic acid, itaconic acid, and maleic acid, and anhydrides of these fatty acids, and the like.

As the protective colloid assistant used to obtain stable particles while stably polymerizing the vinyl chloride monomer, for example, a protective colloid composition having a hydration degree of 31 to 90% by weight and a viscosity of 4% aqueous solution at room temperature of 10 to 60 cps A polyvinyl alcohol resin, at least one selected from the group consisting of cellulose and an unsaturated organic acid having a methoxy group content of 15 to 40% by weight, a hydroxyl group content of 3 to 20% by weight and a 2% aqueous solution viscosity measured at room temperature of 10 to 20,000 cps Can be used within the range of 0.03 to 5 parts by weight based on 100 parts by weight of the vinyl chloride monomer.

For reference, liquid droplet stability is lowered below the lower limit value, and when the upper limit value is exceeded, the fish eye characteristic can be remarkably reduced by forming the beads.

As a specific example, the protective colloid preparation may be a polyvinyl alcohol resin having a degree of hydration of 85 to 98% (high water-solubility resin), a vinyl alcohol resin having a water-solubility of 62 to 82% (water-insolubility resin) % Of a polyvinyl alcohol resin (low hydration resin), and a cellulose suspension stabilizer.

The blending ratio of the high-, middle-, and low-hydration resins is adjusted according to the target physical properties. In the present invention, it may be preferable to mix and use three kinds of high-, medium- and low-hydration resins.

As another example, the protective colloid preparation may contain 0.04 parts by weight of a polyvinyl alcohol resin having a degree of hydration of 85 to 98% (high water-solubility resin), 0.05 parts by weight of a vinyl alcohol resin having a degree of hydration of 62 to 82% And 0.02 parts by weight of a vinyl alcohol resin (low hydration resin) having a hydration degree of 50 to 60% and 0.01 part by weight of a cellulose suspension stabilizer.

The unsaturated organic acid may be at least one selected from acrylic acid polymer, methacrylic acid polymer, itaconic acid polymer, fumaric acid polymer, maleic acid polymer, succinic acid polymer and gelatin.

Examples of the polymerization initiator used in the present invention include diacyl peroxides such as dicumyl peroxide, dipentyl peroxide, di-3,5,5-trimethylhexanoyl peroxide and diaryl peroxide, diisopropyl peroxide Butyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxyneodecanoate, Amyl peroxyneodecanoate, cumyl peroxyneodecanoate, cumyl peroxyneoheptanoate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, and the like, azobis- Azo compounds such as 2,4-dimethylvaleronitrile, and sulfates such as potassium persulfate and ammonium persulfate. These may be used alone or in combination of two or more.

The content of the polymerization initiator is determined by various factors such as the production process, productivity, quality, etc. The total content of the polymerization initiator may be 0.02 to 0.2 parts by weight, or 0.04 to 0.12 parts by weight based on 100 parts by weight of the total amount of the vinyl chloride monomer.

In the present invention, an antioxidant may be applied to stop the suspension polymerization reaction.

As the antioxidant, it is sufficient to use a kind used in the production of the vinyl chloride polymer, and examples thereof include triethylene glycol-bis- [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate Butylhydroxyanisole, n-octadecyl-3- (4-hydroxy-3,5-di-t-butylphenyl) propionate, 2,5 Di-t-butylhydroquinone, 4,4-butylidenebis (3-methyl-6-t-butylphenol), t- butylcatechol, 4,4-thiobis -Cresol) and tocopherol, amine compounds such as N, N-diphenyl-p-phenylenediamine and 4,4-bis (dimethylbenzyl) diphenylamine, dodecylmercaptan, 1,2- Phenyl-2-thiol and the like, phosphoric acid antioxidants such as triphenyl phosphite, diphenyldecyl phosphite, phenyl isodecyl phosphite, tri (nonylphenyl) phosphite and triruryl trithiophosphite Or two or more species And it can be used.

In the present invention, the polymerization system, chain transfer agent, pH adjuster, antioxidant, crosslinking agent, antistatic agent, anti-scale agent and surfactant may be added to the polymerization system before or after the polymerization is started, can do.

The reactor used in the present invention may be an agitator commonly used in the suspension polymerization of a vinyl chloride polymer. For example, the agitator may be a paddle type, a pitched paddle type, a bloomers a baffle plate, a cylindrical type, a D-type, a baffle type, and the like can be used as a baffle type, a baffle type, a gin type, a pfaudler type, a turbine type, a propeller type, A loop type, a finger type, or the like can be used.

The vinyl chloride polymer slurry obtained in the suspension polymerization can be provided with a high quality vinyl chloride polymer through a process of removing water by a fluidized bed drier and drying it under ordinary reaction conditions .

Hereinafter, preferred embodiments of the present invention will be described in order to facilitate understanding of the present invention, but the present invention is not limited thereto.

Example  One

500 ppm of aluminum sulfate was uniformly applied to the inner wall of a 5 L stainless steel polymerization reactor equipped with a reflux condenser and a stirrer, and the jacket temperature was raised to 80 degrees and maintained for 10 minutes. Thereafter, 0.012 part by weight of polyvinyl alcohol having a degree of hydration of 88%, a polyvinyl alcohol having a degree of hydration of 72%, 0.03 part by weight of polyvinyl alcohol having a degree of hydration of 55%, 0.022 part by weight of polyvinyl alcohol having a degree of hydration of 55% 0.006 part by weight of hydroxypropylmethylcellulose and 0.080 part by weight of t-butylperoxyneodecanonate (BND) were added. Then, the inside of the autoclave was degassed with a vacuum pump while stirring, 1200 g of vinyl chloride monomer (100 parts by weight) the polymerization while maintaining the reference temperature 58 ℃ to achieve an average polymerization degree of 1000 and proceed with the polymerization reaction the reactor pressure to the group to the target temperature during the reaction process before the polymerization was stopped at the time that the 1.0 kg / cm ² changes.

Unreacted monomers were recovered and the resin slurry was recovered in a polymerization reactor. The slurry thus obtained was dried in a fluidized bed drier by a conventional method to obtain a vinyl chloride polymer.

Example  2

Polymerization was carried out under the same conditions as in Example 1, except that 0.05 part by weight of aluminum sulfate was continuously added at the point of time when the polymerization conversion rate was 30 to 80%, instead of coating aluminum sulfate before polymerization in Example 1, Respectively.

For reference, the conversion of the polymerization was measured using a butanin tracer equipped with a gas chromatograph. For reference, it is possible to precisely measure the polymerization conversion ratio according to polymerization conditions by preparing a polymerization conversion curve according to the ratio of vinyl chloride monomer and butane over time under a certain polymerization condition at each polymerization condition.

Example  3

The procedure of Example 1 was repeated except that 0.025 part by weight of aluminum sulfate was added at 30% progress of polymerization and 0.025 part by weight of aluminum sulfate was added at 60% And the polymerization was carried out.

Example  4

Polymerization was carried out under the same conditions as in Example 1, except that 0.05 parts by weight of aluminum sulfate was added at the time when 60% polymerization proceeded, instead of coating aluminum sulfate before polymerization in Example 1.

Comparative Example  One

Polymerization was conducted and evaluated under the same conditions as in Example 1 except that aluminum sulfate was not applied to the reactor before polymerization in Example 1 above.

Comparative Example  2

Polymerization was conducted and evaluated in the same manner as in Example 1, except that 0.05 part by weight of a phenolic compound instead of aluminum sulfate was dissolved in a basic aqueous solution and coated on the inner wall of the reactor before the polymerization in Example 1.

[Test Example]

The physical properties of the vinyl chloride polymer prepared in each of Examples 1 to 4 and Comparative Examples 1 and 2 were measured by the following methods, and the results are shown in Tables 1 and 2 below.

* Average particle size: Measured by ASTM D-1243-79.

* Apparent Specific Gravity (BD): Measured according to ASTM D 1895-89.

* Plasticizer absorption rate (% by weight): The amount of dioctyl phthalate (DOP) absorbed into the sample according to ASTM D 3367-95 is expressed in weight% with respect to the sample weight before absorption.

* Thermal Stability: The dried vinyl chloride polymer was placed in an oven at 195 ° C. and the time required for it to become black was measured.

* Whether or not the scale is generated : The scale attached to the agitator and the baffle is weighed and measured after cleaning the reactor after polymerization.

* Fish eye number (fish-eye) (dog): a vinyl polymer 100 parts by weight of dioctyl phthalate chloride (DOP) 45 parts by weight of stearic acid, barium, 0.1 part by weight of tin based stabilizer, 0.2 parts by weight of carbon black 0.1 parts by weight of 140 ℃ Kneaded using a 6-inch roll of 4 mm thick to prepare a sheet having a thickness of 0.3 mm and the number of white transparent particles in 100 cm ² of the sheet.

Metrics Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Average particle diameter (占 퐉) 145 148 144 146 145 160 Apparent Specific Gravity (g / cc) 0.52 0.53 0.51 0.51 0.52 0.57 Plasticizer absorption rate (%) 27.5 27.7 26.9 27.0 25.5 22.0 Thermal stability (min) 77 76 75 77 74 62 Scale occurrence 2g 3g 2.8 g 3g 62g 21 Fishy Eye (Dog) 5 8 7 5 45 25

As shown in Table 1, in the case of Example 1 in which the reactor was coated with aluminum sulfate prior to the initiation of the polymerization reaction, the plasticizer absorptivity, thermal stability, occurrence of scale, Comparative Example 1 in which aluminum sulfate was not added in terms of water- It was confirmed that the contrast enhancement effect of Comparative Example 2 was replaced. In addition, similar or similar effects to those of Examples 2 to 4 and Example 1 in which continuous, intermittent, and temporary dosing were performed in place of the reactor coating of Example 1 were confirmed.

Furthermore, the following additional experimental examples were conducted to examine the further effect of the change in the content of aluminum sulfate, the change in the injection time, etc. in the above Examples 2 to 4.

Add Experimental Example  One:

Polymerization was carried out under the same conditions as in Example 2 except that 0.003 part by weight of aluminum sulfate was continuously added instead of 0.05 part by weight of aluminum sulfate at the time of 30 to 80% Respectively.

Add Experimental Example  2:

Polymerization was carried out under the same conditions as in Example 2 except that 0.15 part by weight of aluminum sulfate was continuously added instead of 0.05 part by weight of aluminum sulfate at 30 to 80% Respectively.

Add Experimental Example  3:

Polymerization was conducted and evaluated under the same conditions as in Example 3, except that 0.05 parts by weight of aluminum sulfate was continuously added when the polymerization proceeded 10 to 30% in Example 3 above.

Add Experimental Example  4:

Polymerization was carried out under the same conditions as in Example 3 except that 0.05 part by weight of aluminum sulfate was continuously added from the time when 80% of the polymerization proceeded to the end of the reaction in Example 3.

Add Experimental Example  5:

Polymerization was carried out under the same conditions as in Example 1 except that 0.0015 parts by weight of aluminum sulfate was added at the time when the polymerization proceeded at 30% in Example 1, and 0.0015 parts by weight of aluminum sulfate was added at the time of 60% progress.

Add Experimental Example  6:

Polymerization was carried out under the same conditions as in Example 1 except that 0.075 part by weight of aluminum sulfate was added at the time when the polymerization proceeded at 30% in Example 1 and 0.075 part by weight of aluminum sulfate was added at the time of 60% progress.

Metrics Additional Experimental Example 1 Further Experimental Example 2 Further Experimental Example 3 Further Experimental Example 4 Further Experimental Example 5 Further Experimental Example 6 Average particle diameter (占 퐉) 142 170 165 147 144 162 Apparent specific gravity
(g / cc) 0.52 0.58 0.51 0.49 0.57 0.56 Plasticizer absorption rate (%) 26.8 20.3 23.9 23.5 25.9 23.9 Thermal stability (min) 72 77 75 76 72 79 Scale occurrence 30 45 28 49 19 13 Fishy Eye (Dog) 32 28 23 42 19 36

As shown in Tables 1 and 2, when the results of Example 2 in which aluminum sulfate was continuously added at a polymerization conversion rate of 30 to 80% and in Experimental Examples 1 and 2 in which the amount of aluminum sulfate was adjusted were compared, . Specifically, the addition of 0.005 parts by weight or less of the additive test example 1 showed insufficient effect of preventing scale, and the additive test sample 2 of 0.15 parts by weight or more showed a significant change in physical properties.

Further, when the results of Experimental Examples 5 and 6 in which aluminum sulfate was separately added at a polymerization conversion rate of 30 to 80% were compared with Example 1, in Experiment Example 5 in which the total amount was less than 0.005 part by weight, And in Experimental Example 6 in which the total amount is 0.15 part by weight, it is confirmed that the physical properties are adversely affected.

Further, by comparing the results of Experimental Examples 3 and 4 in which the injection timing is controlled, the effects of the injection timing can be confirmed. Specifically, Experimental Example 3 added at a conversion rate of less than 30% influenced particle size and physical properties, and it was confirmed that Scale removal was not effective in the additional Experimental Example 4 in which the conversion rate exceeded 80%.

Thus, in Examples 1 to 4 according to the method of the present invention, it was found that it is possible to provide the simplest and most advantageous process in economical aspects such as scale inhibition, .

Claims (12)

A suspension polymerization system comprising a suspension stabilizer, a polymerization initiator and a vinyl chloride monomer, wherein the polymerization system comprises a trivalent metal sulfate.
The method according to claim 1,
Wherein said trivalent metal sulphate is contained as an inner coating of a suspension polymerization reactor.
The method according to claim 1,
Wherein the trivalent metal sulfate is contained as an inner coating of a reflux condenser provided in a suspension polymerization reactor.
The method according to claim 1,
Wherein the trivalent metal sulfate is included in the reactor during polymerization.
5. The method of claim 4,
Wherein the trivalent metal sulfate is contained at a point of 30-80% conversion of the polymerization.
5. The method of claim 4,
Wherein the trivalent metal sulfate is continuously charged, intermittently charged or batch charged.
The method according to claim 1,
Wherein the trivalent metal sulfate is present in an amount of 0.005 to 0.1 part by weight based on 100 parts by weight of the vinyl chloride monomer used in the suspension polymerization.
The method according to claim 1,
Wherein the trivalent metal sulfate is aluminum sulfate.
The method according to claim 1,
The suspension stabilizer has a vinyl alcohol-based resin having a hydration degree of 30 to 90% by weight and a viscosity of 4 to 5% aqueous solution at room temperature of 10 to 60 cps, a methoxy group of 15 to 40% by weight and a hydroxylated propyl group of 3 to 20% The suspension polymerization system according to claim 1, wherein the 2% aqueous solution measured at room temperature has a viscosity of 10 to 20,000 cps and is at least one selected from the group consisting of cellulose and unsaturated organic acids.
The method according to claim 1,
Wherein the suspension stabilizer is in the range of 0.03 to 5 parts by weight based on 100 parts by weight of the vinyl chloride monomer used in the suspension polymerization.
The method according to claim 1,
Wherein the amount of the polymerization initiator is in the range of 0.02 to 0.2 parts by weight based on 100 parts by weight of the vinyl chloride monomer used in the suspension polymerization.
A process for producing a vinyl chloride-based polymer characterized by using a suspension polymerization system according to any one of claims 1 to 11.