KR101987438B1 - Preparing method for polyvinyl chloride polymer - Google Patents
Preparing method for polyvinyl chloride polymer Download PDFInfo
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- KR101987438B1 KR101987438B1 KR1020150066869A KR20150066869A KR101987438B1 KR 101987438 B1 KR101987438 B1 KR 101987438B1 KR 1020150066869 A KR1020150066869 A KR 1020150066869A KR 20150066869 A KR20150066869 A KR 20150066869A KR 101987438 B1 KR101987438 B1 KR 101987438B1
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/12—Polymerisation in non-solvents
- C08F2/16—Aqueous medium
- C08F2/18—Suspension polymerisation
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F14/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen
- C08F14/02—Monomers containing chlorine
- C08F14/04—Monomers containing two carbon atoms
- C08F14/06—Vinyl chloride
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/12—Polymerisation in non-solvents
- C08F2/16—Aqueous medium
- C08F2/20—Aqueous medium with the aid of macromolecular dispersing agents
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J3/00—Processes of treating or compounding macromolecular substances
- C08J3/02—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques
- C08J3/03—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in aqueous media
- C08J3/07—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in aqueous media from polymer solutions
Abstract
The present invention relates to a process for producing a vinyl chloride polymer by suspension polymerization, comprising the step of increasing the stirring speed of the reaction mixture at a time when 60 to 85% of the total polymerization time has elapsed in the suspension polymerization process, According to the production process of the vinyl chloride polymer of the present invention, since the foaming can be suppressed by increasing the stirring speed in the suspension polymerization process of the vinyl chloride polymer, the vinyl chloride polymer used in the suspension polymerization of the vinyl chloride polymer It is possible to suppress the rise of the foam and adhesion of the scale in the reactor and the reflux condenser tube and to maintain the high production efficiency and also the produced vinyl chloride polymer can have excellent physical properties and thus can be used for the production of the vinyl chloride polymer have.
Description
The present invention relates to a process for producing a vinyl chloride polymer, and more particularly, to a process for producing a vinyl chloride polymer capable of suppressing the rise of foams that can occur in the production of a vinyl chloride polymer, and thus, the adhesion of a scale to a reactor and a reflux condenser tube And a manufacturing method thereof.
The vinyl chloride polymer refers to an interpolymer obtained by polymerizing a mixture of vinyl chloride or a vinyl chloride and a copolymerizable monomer. Polyvinylchloride (PVC) has been used in various fields because it is inexpensive, has excellent quality balance and processability. Further, by controlling the polymerization temperature, it is possible to produce polymers having different polymerization degrees, and they have different properties depending on the degree of polymerization, so that they can be applied to two fields, hard and soft. In the hard field, it is used for pipes, films, window frames, etc. In the soft field, it is used for electric cable coating, wrap film, sheet and the like.
Polymerization methods of vinyl chloride polymers include emulsion polymerization and suspension polymerization. Among them, in the case of emulsion polymerization, polymerization is carried out by using water, an emulsifier, a vinyl chloride monomer, an initiator, etc. The vinyl chloride polymer produced by the emulsion polymerization method has excellent viscosity stability, And it is also widely used as a flooring material because of its excellent foaming property. On the other hand, in the case of suspension polymerization, polymerization is carried out by using water, a dispersant, a vinyl chloride monomer, and an initiator. Since the polymerization is carried out with particles of about 150 μm, processing is possible immediately after drying. The vinyl chloride polymer thus polymerized has excellent electrical insulation properties and is excellent in chemical resistance and is widely used as a chemical container.
Typically, suspension polymerization of a vinyl chloride monomer is carried out batchwise. After adding a vinyl chloride monomer and an initiator additive, steam is added to the jacket of the polymerization reactor, and warm water is circulated to raise the polymerization temperature to initiate the polymerization reaction And when heat is generated by an exothermic reaction, cooling water is flowed into the jacket to maintain the polymerization temperature, and the vinyl chloride polymer is polymerized. An example of such a polymerization method is disclosed in Korean Patent Publication No. 2010-0005281.
When the vinyl chloride monomer is subjected to suspension polymerization, a foam is formed. The foam can be divided into two types: wet foam at the initial stage of polymerization and dry foam at the end of polymerization. The wet foam occurs due to the effect of the initial dispersing agent in polymerization, and the dry foam is formed by the combination of the PVC particles and the wet foam, which are generated as the PVC particles are produced at the end of the polymerization.
The dry foam rises to the top of the reactor where the polymerization takes place, reaches the reflux condenser and attaches to the upper part of the reactor and the reflux condenser tube. The upper part of the reactor and the reflux condenser tube are washed Since it is a difficult position to clean in the step, the attached foam will form a scale.
The scale thus formed is added to the newly introduced monomer in the reactor during the next polymerization of the vinyl chloride polymer, and is then reacted again. In this case, since the PVC particles included in the dry foam on which the scale is formed are re-polymerized, the plasticizer absorption rate is remarkably low and the formation of particles having a large size is caused, so that the PVC particles are not melted smoothly during the resin processing, There is a problem.
In addition, the dry foam reaching the upper part of the reactor and the reflux condenser remarkably lowers the heat transfer efficiency, thereby lowering the heat removal efficiency of the reflux condenser, reducing the conversion rate, and difficulty in washing the reactor.
Therefore, it is important to prevent the level of the dry foam from increasing during the reaction in order to ensure high product properties, i.e. low fish eye content, while maintaining high production efficiency.
In order to solve such a problem, various methods have been proposed. For example, Japanese Patent Application Laid-Open Nos. 2-180908 and 7-286003 disclose a method of adding a defoaming agent in polymerization of a vinyl chloride polymer . However, although the addition of the defoaming agent can exert an effect in suppressing the foam of the reaction system, there is a problem that the defoaming agent affects the particle formation of the polymer, thereby deteriorating the physical properties of the polymer.
Therefore, in the polymerization of vinyl chloride polymers, there is a demand for the development of a novel method capable of effectively suppressing foam generation and scale adhesion to the reactor and the reflux condenser tube through a simpler method.
A problem to be solved by the present invention is to provide a polyvinyl chloride copolymer which is capable of suppressing the generation of foam during polymerization of the vinyl chloride polymer and the adhesion of scale to the reactor and the reflux condenser tube due to the increase thereof, And a method for producing the vinyl chloride polymer.
In order to solve the above problems, the present invention provides a process for producing a vinyl chloride polymer by suspension polymerization, comprising the steps of: increasing the stirring speed of the reaction mixture at a time when 60 to 85% Wherein the vinyl chloride polymer is a polyvinyl chloride copolymer.
According to the process for producing a vinyl chloride polymer of the present invention, the foaming can be suppressed by increasing the stirring speed in the suspension polymerization process of the vinyl chloride polymer. Therefore, in the reactor used in the suspension polymerization of the vinyl chloride polymer and in the reactor used in the reflux condenser tube The rise of the foam and the adhesion of the scale can be suppressed, high production efficiency can be maintained, and the produced vinyl chloride polymer can have excellent physical properties, so that it can be usefully used in the production of vinyl chloride polymer.
Hereinafter, the present invention will be described in detail in order to facilitate understanding of the present invention.
The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.
The method for producing a vinyl chloride polymer according to the present invention is a method for producing a vinyl chloride polymer by suspension polymerization, wherein the stirring speed of the reaction mixture is increased at a time when 60 to 85% .
Since the method for producing the vinyl chloride polymer includes a step of increasing the stirring speed of the reaction mixture in the suspension polymerization process, it is possible to suppress the generation of foam, and the reactor used in the suspension polymerization of the vinyl chloride polymer And the increase of the foam level in the reflux condenser tube and hence the adhesion of the scale can be suppressed.
Examples of the foam generated during the suspension polymerization of the vinyl chloride monomer include a wet foam generated at the initial stage of the polymerization by the influence of the dispersing agent and a vinyl chloride polymer (PVC) There is a dry foam generated when the PVC particles and the wet foam are combined. The foam to suppress the generation of the PVC foam through the agitation speed is a dry foam at the end of polymerization.
According to the manufacturing method of the present invention, since the generation of the foam is suppressed by increasing the stirring speed, the rise of the foam in the reactor and the reflux condenser tube and hence the adhesion of the scale can be suppressed, It is possible to prevent lowering of the production efficiency during the suspension polymerization of the monomer and deterioration of the physical properties of the vinyl chloride polymer produced.
The stirring speed may be increased at the time when the dry foam is produced, that is, at the time when the PVC particles having been polymerized are generated. Specifically, the stirring speed is increased when 60 to 85% , And preferably 70 to 75% of the time can be elapsed. At this time, the progress of the reaction during the entire polymerization time may be determined by a method in which the production process of the vinyl chloride polymer by the production method of the vinyl chloride polymer by the suspension polymerization is advanced in advance and the time of the total polymerization time and the generation of the foam are observed .
When the increase of the stirring speed is made before 60% of the total polymerization time has elapsed, the influence of the stability of the polymerization reaction as a whole influences the particle diameter, density, plasticizer absorption rate and porosity of the produced vinyl chloride polymer particles If the increase in the stirring speed exceeds 85% of the total polymerization time, since the polymerization has already proceeded to a considerable extent and a considerable amount of dry foam has been generated, effective foam level increase suppression or scale generation It is difficult to expect a reduction effect.
The degree of increase in the stirring speed may be less than 5 to 20%, preferably 5 to 15%, more preferably 5 to 10% based on the initial stirring speed.
If the amount of increase in the stirring speed is too small, the effect of preventing the formation of foam and the effect of inhibiting the foam level from rising in the reactor are inferior. If the amount of increase in the stirring speed is too large, The particle diameter of the vinyl chloride polymer may be increased, and the physical properties of the vinyl chloride polymer may be different from that expected when the polymerization is carried out while maintaining the initial stirring speed. In addition, . The degree of increase of the stirring speed can be suppressed when the stirring speed is increased to 5% or more based on the initial stirring speed. When the increase in the stirring speed is less than 20%, the amount of the vinyl chloride polymer particles It is possible to prevent a change in physical properties, such as an increase in particle diameter.
The initial stirring speed can be a speed conventionally used to produce a vinyl chloride polymer and can be adjusted according to the properties of the desired vinyl chloride polymer. Thus, although not particularly limited, for example, in one example of the present invention, the initial stirring speed may be in the range of more than 180 to less than 220 rpm, preferably 190 to 210 rpm, more preferably 195 to 205 rpm.
The suspension polymerization can be carried out at a polymerization temperature of the vinyl chloride polymer by conventional suspension polymerization. When the temperature is lowered, the number average degree of polymerization of the vinyl chloride polymer is increased. When the temperature is elevated, the vinyl chloride polymer has a number average degree of polymerization . For example, in one example of the present invention, the suspension polymerization may be carried out at a temperature of 30 to 80 캜, preferably 50 to 70 캜.
Hereinafter, an example of a method for producing a vinyl chloride polymer by suspension polymerization of the present invention is shown, but the production method of the present invention is not limited thereto.
A method for producing a vinyl chloride polymer according to an embodiment of the present invention includes the steps of (1) mixing a water, a vinyl chloride monomer, a dispersant, and an initiator to prepare a reaction mixture; (2) stirring the reaction mixture; (3) increasing the stirring speed when 60 to 85% of the total reaction time has elapsed; And (4) maintaining the increased stirring speed until the end of the reaction.
In the step (1), a vinyl chloride monomer, a dispersant, and an initiator are mixed with water to prepare a reaction mixture.
The water is a polymerization solvent, and the temperature of the water can be appropriately selected in consideration of the temperature at which the suspension polymerization is carried out.
The vinyl chloride polymer of the present invention may be a resin made of a pure vinyl chloride monomer but may be a mixture of a vinyl chloride monomer mainly composed of a vinyl chloride monomer and a vinyl monomer copolymerizable therewith ).
Examples of the vinyl monomer copolymerizable with the vinyl chloride monomer include olefin compounds such as ethylene and propylene; Vinyl esters such as vinyl acetate and vinyl propionate; unsaturated nitriles such as acrylonitrile; Vinyl alkyl ethers such as vinyl methyl ether and vinyl ethyl ether; And unsaturated fatty acids such as acrylic acid, methacrylic acid, itaconic acid, and maleic acid, and anhydrides of these fatty acids. Monomers copolymerizable with vinyl chloride monomers may be used alone or in admixture of two or more.
In order to maintain the stability of the vinyl chloride monomer in the production process of the vinyl chloride polymer, the dispersant is used in order to obtain properties such as the average particle diameter, the apparent specific gravity (BD), and the plasticizer absorptivity (CPA) of the desired degree of vinyl chloride polymer The dispersant may be, for example, a vinyl alcohol-based resin having a hydration degree of 30 to 90% by weight and a viscosity of 4% aqueous solution at room temperature of 5 to 100 cps, a methoxy group of 15 to 40% Cellulose acetate and unsaturated organic acids having a viscosity of from 2 to 20,000 cps measured at room temperature and having a viscosity of from 3 to 20% by weight and a degree of hydration of from 30 to 90% by weight %, A viscosity of 5% to 100% by weight of a 4% aqueous solution at room temperature, a methoxy group content of 15 to 40% by weight and a propylhydroxyl group content of 3 to 20% by weight A viscosity of a 2% aqueous solution measured at room temperature may be from 10 to 20,000 cps in the cellulose, or a mixture thereof, more preferably is a moisture content of 50 to 98% of a mixture of vinyl alcohol-based resin and a cellulose resin. The dispersant may be 0.03 to 5 parts by weight, and preferably 0.05 to 2.5 parts by weight based on 100 parts by weight of the vinyl chloride monomer. When the amount of the dispersant is 0.03 parts by weight or more, the stability of the droplet can be improved. When the amount of the dispersant is less than 5 parts by weight, the formation of fish eyes can be prevented from increasing due to the formation of coarse PVC particles.
On the other hand, in one embodiment of the present invention, the dispersant may include a mixture of two or more vinyl alcohol resins having different degrees of hydration, for example, a vinyl alcohol resin (high hydration resin) having a hydration degree of 85 to 98% (Hydration degree resin) having a degree of hydration of 62 to 82% and a vinyl alcohol-based resin having a degree of hydration of 50 to 60% (low hydration degree resin) The content of the respective vinyl alcohol based resins is from 0.01 to 0.06 parts by weight of a vinyl alcohol based resin having a hydration degree of 85 to 98% based on 100 parts by weight of the vinyl chloride based monomer, and the vinyl alcohol based resin having a hydration degree of 62 to 82% 0.01 to 0.06 part by weight, and a vinyl alcohol resin having a hydration degree of 50 to 60%. The dispersant may contain the cellulose in addition to the vinyl alcohol resin. The cellulose may be included in an amount of 0.001 to 0.02 part by weight based on 100 parts by weight of the vinyl chloride monomer.
Examples of the initiator include diacyl peroxides such as dicumyl peroxide, dipentyl peroxide, di-3,5,5-trimethylhexanoyl peroxide and diarooyl peroxide, diisopropyl peroxydicarbonate, di-sec Butyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, and other peroxydicarbonates, t-butyl peroxyneodecanoate, t-butyl peroxyneoheptanoate, t-amyl peroxyneodecano Peroxyesters such as cumyl peroxyneodecanoate, cumyl peroxyneoheptanoate and 1,1,3,3-tetramethylbutyl peroxyneodecanoate, azobis-2,4-dimethylvalerate And nitrates such as nitrile and ronitril, and sulfates such as potassium persulfate and ammonium persulfate, and they may be used alone or in combination of two or more.
The amount of the initiator to be used may be determined according to factors such as the manufacturing process, productivity, quality, etc., and may be used in an amount of 0.02 to 0.2 parts by weight, preferably 0.04 to 0.12 parts by weight, based on 100 parts by weight of the vinyl chloride monomer . When the amount of the initiator used is more than 0.02 parts by weight, the reaction time is promoted to improve the productivity. When the amount of the initiator is less than 0.2 parts by weight, the initiator is not completely consumed during the polymerization and remains in the final resin product, Can be prevented.
In the step (2), the reaction mixture is stirred, and suspension polymerization can be performed through the stirring.
The stirring speed may be a speed conventionally used to produce the vinyl chloride polymer, and may be adjusted depending on the physical properties of the desired vinyl chloride polymer. Thus, although not particularly limited, for example, in one example of the present invention, the initial stirring speed may be in the range of more than 180 to less than 220 rpm, preferably 190 to 210 rpm, more preferably 195 to 205 rpm.
Then, in the step (3), the stirring speed is increased when 60 to 85% of the total reaction time has elapsed.
Through the step of increasing the stirring speed, it is possible to suppress the occurrence of foam during the suspension polymerization of the vinyl chloride polymer, and it is possible to suppress the foam level in the reactor and the reflux condenser tube used in the suspension polymerization of the vinyl chloride polymer, And thus the adhesion of the scale can be suppressed. Therefore, it is possible to prevent the lowering of the production efficiency during the suspension polymerization of the vinyl chloride monomer and the deterioration of the physical properties of the produced vinyl chloride polymer.
The stirring speed may be increased at the time when the dry foam is produced, that is, at the time when the PVC particles having been polymerized are generated. Specifically, the stirring speed is increased when 60 to 85% , And preferably 70 to 75% can be reached at the elapsed time
Next, in the step (4), the increased stirring speed is maintained until the end of the reaction.
The end of the reaction can be determined by measuring the pressure change of the reactor in which the vinyl chloride polymer is polymerized. The pressure of the reactor is 0.6 to 2.0 kg / cm 2 , preferably 1.0 to 1.5 kg / cm 2 The polymerization can be stopped at a point of time when it is lowered.
The vinyl chloride polymer prepared according to the above-mentioned polymerization stop may be in the form of a slurry, and the slurry may be produced in the form of a final vinyl chloride polymer by removing moisture with a fluid bed drier under ordinary reaction conditions.
In the present invention, a polymerization regulator, a chain transfer agent, a pH adjuster, an antioxidant, a crosslinking agent, an antistatic agent, a scale inhibitor and a surfactant may be added to the polymerization system before or after the initiation of polymerization, Some of them may be added partly or continuously.
The antioxidant is not particularly limited as long as it is an antioxidant generally used in the production of a vinyl chloride polymer, and examples thereof include triethylene glycol-bis- [3- (3-t-butyl-5-methyl- Propionate, hydroquinone, p-methoxyphenol, t-butylhydroxyanisole, n-octadecyl 3- (4-hydroxy-3,5-di- T-butylhydroquinone, 4,4-butylidenebis (3-methyl-6-t-butylphenol), t-butylcatechol, -m-cresol) and tocopherol, amine compounds such as N, N-diphenyl-p-phenylenediamine and 4,4-bis (dimethylbenzyl) diphenylamine, dodecyl mercaptan, Sulfur compounds such as diphenyl-2-thiol, phosphoric acid-based compounds such as triphenylphosphite, diphenyldecylphosphite, phenylisodecylphosphite, tri (nonylphenyl) phosphite and trilauryltithiophosphite It may be the jije.
The average degree of polymerization of the vinyl chloride polymer produced according to the production method of the present invention may be 500 to 3,000.
The reactor in which the polymerization is carried out is not particularly limited as long as it is a stirring apparatus generally used in suspension polymerization of a vinyl chloride polymer. For example, as a stirrer, a stirring blade type may be a paddle type, a pitched paddle type, a baffler type, a baffler type, a baffler type, a bloomer gin type, a pfaudler type, a turbine type and a propeller type stirrer. The baffle may be a plate type, a cylindrical type, a D type, a loop type, These may be used alone or in combination of two or more stirring blades.
Example
Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples, but the present invention is not limited by these Examples and Experimental Examples. The embodiments according to the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to enable those skilled in the art to more fully understand the present invention.
Example One
Reflux condenser and a stirrer to polymerizer stainless polymerization of the attached inner volume of 1 m 3 140 parts by weight of a moisture content of 88% of polyvinyl alcohol 0.02 parts by weight of a moisture content of 72% of the 0.03 parts by weight of polyvinyl alcohol, moisture content 0.025 part of polyvinyl alcohol having 55% of hydroxyl value, 0.005 part of hydroxypropylmethylcellulose and 0.088 part of t-butylperoxyneodecanonate (BND) were added and stirred at 200 rpm with a vacuum pump , And 100 parts by weight of a vinyl chloride monomer was added thereto.
The reaction was continued while maintaining the temperature of the polymerization reactor at 57 ° C. throughout the reaction. When the reaction time was 70 to 75%, stirring was continued at 210 rpm with increasing the stirring speed by 5% The polymerization was stopped at the point of change of 1.2 kg / cm 2 .
0.05 parts by weight of triethylene glycol-bis- [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] as an antioxidant was added to the solution, and unreacted monomers were recovered. And 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
A vinyl chloride polymer was prepared in the same manner as in Example 1 except that the stirring speed was increased to 220 rpm at 10% instead of 5% at the middle of the reaction.
Comparative Example One
A vinyl chloride polymer was prepared in the same manner as in Example 1, except that the stirring speed was maintained at 200 rpm without increasing the stirring speed in the middle of the reaction.
Comparative Example 2
A vinyl chloride polymer was prepared in the same manner as in Example 1, except that the stirring speed was 180 rpm, and 180 rpm was maintained in the middle of the reaction without increasing the stirring speed.
Comparative Example 3
A vinyl chloride polymer was prepared in the same manner as in Example 1, except that the stirring speed was 220 rpm and 220 rpm was maintained without increasing the stirring speed in the middle of the reaction.
Comparative Example 4
A vinyl chloride polymer was prepared in the same manner as in Example 1, except that the stirring speed was increased to 240 rpm at 20% instead of 5% in the middle of the reaction.
Comparative Example 5
The time point at which the stirring speed was increased in the middle of the reaction was set to be when the reaction time was 85 to 90%, not when the reaction time was 70 to 75%, and the stirring speed was increased to 220% , A vinyl chloride polymer was prepared in the same manner as in Example 1.
Comparative Example 6
The time point at which the stirring speed was increased in the middle of the reaction was set to be when the reaction time was 85 to 90%, not when the reaction time was 70 to 75%, and the stirring speed was increased to 20% instead of 5% , A vinyl chloride polymer was prepared in the same manner as in Example 1.
Comparative Example 7
A vinyl chloride polymer was prepared in the same manner as in Example 1, except that the stirring speed was changed from 5% to 10% in the middle of the reaction at 180 rpm.
Experimental Example
The foam level (foam height) and the physical properties of the prepared vinyl chloride polymer in the manufacturing process according to Examples 1 and 2 and Comparative Examples 1 to 7 were measured according to the following criteria, Respectively.
Average particle diameter: measured by ASTM D1 243-79.
Apparent Specific Gravity (B.D.): Measured according to ASTM D 1895-89.
Plasticizer Absorption Rate [CPA, (wt%)]: The amount of DOP absorbed by the sample according to ASTM D 3367-95 is expressed as% by weight with respect to the sample before absorption.
100 parts by weight of a vinyl chloride polymer, 45 parts by weight of DOP, 0.1 part by weight of barium stearate, 0.2 part by weight of tin stabilizer and 0.1 part by weight of carbon black were placed in a 6 inch roll at 140 캜 And then kneaded for 4 minutes to form a sheet having a thickness of 0.3 mm and the number of white transparent particles in 100 cm 2 of the sheet.
· Foam level: When the foam is above a certain level in the reactor, the foam level is measured through the foam detector installed at the upper part of the reactor. The higher the number is, the closer to the upper part of the reactor.
One
2
One
2
3
4
5
6
7
(rpm)
(rpm)
(g / cm 3)
In Table 1, RPM-1 represents the point of time when the reaction speed is changed from 70 to 75% based on the reaction time, and RPM-2 represents the point of time when the stirring speed is changed in the middle of dry- , And the reaction time is 85 to 90% based on the reaction time.
Referring to Table 1, Examples 1 and 2 show that by increasing the stirring speed of 5% and 10% from the initial stirring speed of 200 rpm at 70 to 75% of the reaction time based on the reaction time, It was confirmed that the foam level was lowered and the number of fish eyes was reduced as compared with Comparative Example 1 in which 200 rpm was maintained. At this time, the size of the particle diameter increased by several micrometers as the stirring speed increased, but the apparent specific gravity (BD) and the plasticizer absorptivity (CPA) hardly changed, and the change in physical properties of the prepared vinyl chloride polymer due to the increase in the stirring speed .
In Comparative Examples 2 and 3, polymerization was carried out while maintaining a relatively slow initial stirring speed of 180 rpm, and polymerization progressed at a relatively early initial stirring speed of 220 rpm.
The results of Comparative Examples 2 and 3 show that the Comparative Example 2 in which the reaction was maintained at a relatively slow initial stirring speed of 180 rpm as compared with Examples 1 and 2 and Comparative Example 1 showed a high foam level during polymerization, It was confirmed that the physical properties of the vinyl chloride polymer prepared were changed such that the particle size of the obtained vinyl chloride polymer was large and the fish eye generation was increased according to the increase of the particle size of the polymer at the high foam level and the porosity was low and the plasticizer absorption rate was low In addition, in Comparative Example 3 where the reaction was maintained at a relatively early initial stirring speed of 220 rpm, an increase in foam level and an inhibition effect on fish eye were confirmed, and an increase in porosity and an increase in plasticizer absorption were observed, It was confirmed that the physical properties of the produced vinyl chloride polymer were changed by reducing the particle size of the polymer. Among them, in particular, in the case of Example 2 and Comparative Example 3, there was a difference only at the time when the stirring speed of 220 rpm was attained. In the case of Example 2, while maintaining the physical properties of the polymer prepared in Comparative Example 1, And the inhibition effect on the production of fish eye was observed. On the other hand, in Comparative Example 3, it was confirmed that the physical properties of the prepared vinyl chloride polymer were changed by keeping 220 rpm from the beginning of polymerization.
On the other hand, in Comparative Example 4, the rate of increase in the stirring speed was relatively large as compared with those in Examples 1 and 2, and in Comparative Example 4, the rate of increase in the stirring speed was increased, so that the porosity and plasticizer absorption rate of the prepared polymer were increased, And the effect of suppressing the foam level was increased. However, it was confirmed that the fish eye was increased due to the increase of the particle size of the polymer produced and the occurrence of fish eye.
In Comparative Examples 5 and 6, the increase of the stirring speed was slower than in Examples 1 and 2. In Comparative Examples 5 and 6, the physical properties of the produced polymer were maintained, The effect of suppressing the rise of foam level and the effect of suppressing the occurrence of fish eye were not shown. Particularly, in Comparative Example 6, the rate of increase in the stirring speed was higher than that in Examples 1 and 2, but the effect of suppressing the rise of the foam level and the effect of suppressing the occurrence of fish eye could not be confirmed.
On the other hand, Comparative Example 7 is an example in which the stirring speed is reduced at the time of increasing the stirring speed of Examples 1 and 2. In the case of Comparative Example 7, it was confirmed that as the stirring speed was decreased, the foam level was increased and the fish eye was not only increased, but also the porosity of the polymer was decreased and the plasticizer absorption rate was decreased and the physical properties were changed .
Claims (13)
Increasing the stirring speed of the reaction mixture at a time when 70 to 75% of the total polymerization time has elapsed in the suspension polymerization process,
Wherein the degree of increase of the stirring speed is less than 5 to 20% based on the initial stirring speed.
Wherein the degree of increase in the stirring speed is 5 to 10% based on the initial stirring speed.
Wherein the suspension polymerization is carried out at a temperature of 30 to 80 占 폚.
The suspension polymerization may be carried out,
(1) mixing a water, a vinyl chloride monomer, a dispersant, and an initiator to prepare a reaction mixture;
(2) stirring the reaction mixture;
(3) increasing the stirring speed when 60 to 85% of the total reaction time has elapsed; And
(4) maintaining the increased stirring speed until the end of the reaction.
Wherein the dispersing agent comprises a vinyl alcohol-based resin having a degree of hydration of 50 to 98%.
Wherein the dispersing agent comprises a mixture of two or more vinyl alcohol-based resins having different degrees of hydration.
Wherein the dispersing agent is a vinyl chloride resin containing a mixture of a vinyl alcohol resin having a degree of hydration of 85 to 98%, a vinyl alcohol-based resin having a degree of hydration of 62 to 82% and a vinyl alcohol-based resin having a degree of hydration of 50 to 60% ≪ / RTI >
0.01 to 0.06 parts by weight of a vinyl alcohol resin having a hydration degree of 85 to 98% based on 100 parts by weight of a vinyl chloride monomer, 0.01 to 0.06 parts by weight of a vinyl alcohol resin having a hydration degree of 62 to 82% And 0.01 to 0.03 parts by weight of a vinyl alcohol resin having a degree of hydration of 50 to 60%.
Wherein the dispersing agent further comprises cellulose.
Wherein the dispersing agent comprises the cellulose in an amount of 0.001 to 0.02 parts by weight based on 100 parts by weight of the vinyl chloride monomer.
Wherein the stirring of step (2) is carried out at a rate of more than 180 to less than 220 rpm.
Priority Applications (1)
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| KR101168400B1 (en) | 2008-07-07 | 2012-07-25 | 주식회사 엘지화학 | Suspension polymerization method for polyvinylchloride and polyvinylchloride produced thereby |
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