KR20190046326A - preparation method for Vinyl chloride polymer - Google Patents

Abstract

The present invention relates to a method for manufacturing a vinyl chloride-based polymer. More specifically, the present invention relates to the method for manufacturing the vinyl chloride-based polymer, which controls a surface tension of a polymerization mixture to 44 mN/m or less when manufacturing the vinyl chloride-based polymer, and comprises cellulose with a viscosity of a 2% aqueous solution of 100 to 200 mPa·s in protective colloid preparation, thereby being able to manufacture the vinyl chloride-based polymer having a remarkably improved plasticizer absorption amount and projecting quality of a manufactured polymer and having a high speed of reduction of a residual monomer.

Description

Preparation method for vinyl chloride polymer "

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 producing a vinyl chloride polymer having excellent plasticizer absorption performance and excellent residual monomer volatility.

Generally, a vinyl chloride polymer is a polymer containing 50% or more of vinyl chloride, and is inexpensive, has a low hardness, and can be applied to most processing apparatuses, thus varying application fields. Furthermore, it is a universal resin widely used for living and industrial materials such as films, sheets, molded products and the like, because it has excellent physical and chemical properties such as mechanical strength, weather resistance and chemical resistance, and is widely used for building materials, household articles, automobile interior materials, And so on.

For this reason, research for improving the productivity of a vinyl chloride resin has been developed in the past. For example, in Korean Patent Laid-Open Publication No. 2006-0038100, there is provided a method of dividing monomer into two or more times in order to improve productivity .

Particularly, vinyl chloride resin is widely used not only for hardening of pipes and chassis but also for softening of film, sheet and electric wire by adding various additives such as plasticizer. For example, Korean Patent Registration No. 0838474 , There is provided a vinyl chloride resin composition for forming a transparent soft sheet, which comprises a plasticizer and a stabilizer having a specific structure.

As described above, since the vinyl chloride resin for softening essentially contains a plasticizer, in order to use it as a soft vinyl chloride resin, the vinyl chloride polymer should have excellent compatibility with the plasticizer and the ability to absorb the plasticizer, Internal voids in the vinyl-based polymer must develop.

Further, when the plasticizer absorbing performance is excellent, there is an effect that the quality of the protrusion, which is one of important physical properties, is improved when a product such as a film or a sheet is produced.

Therefore, there is a demand for a technique for producing a vinyl chloride polymer in which the internal voids of the polymer are developed while exhibiting excellent plasticizer-absorbing performance.

In general, it is known to polymerize a secondary dispersant having a low degree of saponification by increasing the content thereof in order to produce a polymer having improved plasticizer absorption performance and improved internal voids. However, the use of an excessive secondary dispersant deteriorates the particle stability in the polymerization process Not only the polymerization instability is caused but also the apparent specific gravity of the produced polymer is low and the productivity of the process is low and there is a difficulty in transportation for actual use.

In order to solve the above problems and to produce a vinyl chloride polymer in which the internal voids of the polymer are developed with excellent plasticizer absorption performance, an optimal combination of dispersants in a vinyl chloride polymerization process is attained through appropriate combination of dispersants having various degree of saponification Research to find out is continuing.

On the other hand, in addition to improving the plasticizer absorption performance, the regulation of reduction of volatile organic compounds (VOC) that can occur in vinyl chloride polymers is increasingly important in various industrial fields such as the construction market, It is becoming. Volatile organic compounds (VOCs) are harmful substances that cause harm to the nervous system through skin contact or respiratory inhalation. They are harmful to the human body and cause secondary pollutants such as photochemical oxide It is also known as a harmful substance. Accordingly, in the world, regulations for the reduction of volatile organic compounds are being implemented, and there is a residual vinyl chloride monomer unreacted as a volatile organic compound even in the vinyl chloride polymer, so that a method for improving the recovery efficiency of the residual monomers in the polymer Which is an important issue in the production process of vinyl chloride polymer.

As described above, there is a need for a process for producing a vinyl chloride-based polymer having improved plasticizer-absorbing performance, improved internal voids, improved vinyl chloride polymer having excellent quality, and improved recovery efficiency of the unreacted monomer as described above have.

KR2006-0038100A (2006.05.03) KR0838474B1 (2008.06.09)

SUMMARY OF THE INVENTION The present invention has been conceived to solve the problems of the prior art described above, and it is an object of the present invention to provide a method for producing a polyvinyl chloride-based polymer by making the surface tension of a polymerization mixture low in a suspension polymerization process, Of a vinyl chloride-based polymer which is excellent in plasticizer-absorbing performance, develops internal voids, and has a high rate of reduction of residual monomers in the polymer, Method.

According to an embodiment of the present invention, there is provided a process for preparing a vinyl chloride polymer by suspension polymerization of a vinyl chloride monomer in the presence of a polymerization mixture to produce a vinyl chloride polymer, A polymerization initiator and a protective colloid auxiliary, wherein the polymerization mixture has a surface tension of 44 mN / m or less and the protective colloid assistant is a vinyl alcohol based resin; And a cellulose-based material having a viscosity of 20 to 2% aqueous solution of 100 to 200 mPa · s.

In the method for producing a vinyl chloride polymer according to an embodiment of the present invention, the surface tension of the polymerization mixture is adjusted to 44 mN / m or less and the viscosity of the vinyl alcohol resin and 2% aqueous solution Is 100 to 200 mPa · s. As a result, the inner pores of the polymer to be produced are improved, the plasticizer absorption performance is excellent, and the absorption amount of the plasticizer is excellent, so that it is confirmed as a fish-eye The projection quality is also significantly improved.

In addition, in the method for producing a vinyl chloride-based polymer according to an embodiment of the present invention, the internal voids of the polymer to be produced are developed, and thus the recovery efficiency of unreacted residual monomers is excellent. Accordingly, the volatile organic compounds in the polymer are reduced It is effective.

Figs. 1 to 4 are diagrams showing time-dependent residual monomer contents in Examples and Comparative Examples. Fig.

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 present invention provides a method for producing a vinyl chloride polymer having excellent plasticizer-absorbing performance, improved protrusion quality, and improved recovery efficiency of unreacted residual monomers.

The method for producing a vinyl chloride polymer according to an embodiment of the present invention includes a step of suspending and polymerizing a vinyl chloride monomer in the presence of a polymerization mixture to prepare a vinyl chloride polymer, A polymerization initiator and a protective colloid auxiliary, wherein the polymerization mixture has a surface tension of 44 mN / m or less and the protective colloid assistant is a vinyl alcohol based resin; And a cellulose-based material having a viscosity of 2 to 100 mPa · s at 20 ° C. in an aqueous 2% solution.

In the present invention, " vinyl chloride-based polymer " may refer to a polymer chain derived from a vinyl chloride-based monomer, which represents a compound produced by polymerizing a vinyl chloride monomer.

In the present invention, " polymerization mixture " refers to the reaction aids present in the reactor prior to initiation of the polymerization reaction, which may mean excluding the vinyl chloride monomer. For example, the polymerization mixture may mean a mixture of at least one of a polymerization initiator, a protective colloid assistant, a polymerization water and various additives, and the surface tension of the polymerization mixture may mean the surface tension of the polymerization mixture.

In the present invention, the unit mPa · s is a unit of viscosity, and 1 mPa · s can be converted into 1 cps (centipoise).

Specifically, the surface tension of the polymerization mixture of the present invention may be from 40 mN / m to 44 mN / m, even more preferably from 42 mN / m to 44 mN / m.

When the surface tension is more than 44 mN / m, the interfacial tension between water and the vinyl chloride monomer is not reduced, and the vinyl chloride polymer which does not induce the active breakage and aggregation of the droplets The absorption performance of the plasticizer is deteriorated, and the quality of the protrusions may deteriorate.

According to an embodiment of the present invention, the polymerization mixture may include polymerized water, a polymerization initiator and a protective colloid assistant, and at the same time, one or more kinds of additives which can be added when the polymer is prepared May include.

The protective colloid assistant maintains the stability of the vinyl chloride monomer in the process of producing the vinyl chloride polymer, and the plasticizer absorbency (CPA), the average particle diameter, the apparent specific gravity (BD) and the particle diameter And the like. The protective colloid preparation may be a vinyl alcohol-based resin having a hydration degree of 30 to 98% and a viscosity of 5 to 100 cps at 4% aqueous solution at room temperature, At least one selected from the group consisting of a cellulose-based substance having a period of 15 to 40% by weight and a hydroxylated propyl group of 3 to 20%, and an unsaturated organic acid, preferably having a degree of hydration of 30 to 98% % Aqueous solution having a viscosity of 5 to 100 cps, a cellulose-based material having a methoxy group content of 15 to 40% and a propylhydroxy group content of 3 to 20%, or It may be a mixture of. In this case, the unit% of the degree of hydration may be interpreted as weight%.

The protective colloid aid may be 0.02 to 5 parts by weight, preferably 0.05 to 2.5 parts by weight, more preferably 0.05 to 1.0 part by weight based on 100 parts by weight of the vinyl chloride monomer. When the amount of the protective colloid adjuvant used is 0.02 parts by weight to 5 parts by weight, the droplet stability and the lump and cracking phenomenon can be appropriately performed during the production of the polymer, so that it is possible to produce a polymer having a desired shape, It is possible to prevent the generation of fish-eye from increasing due to particle formation.

Meanwhile, the protective colloid assistant may include a cellulose-based material as described above, and the cellulose-based material may be added in an amount of 0.001 to 0.1 part by weight, more preferably 0.001 to 0.02 part by weight based on 100 parts by weight of the vinyl chloride- And examples of the cellulose-based material include methylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose and the like, and any one or a mixture of two or more thereof may be used. Among them, hydroxypropylmethylcellulose may be preferably used. The cellulose-based material is more specifically composed of 15 to 40% by weight of methoxy group and 3 to 20% by weight of hydroxypropyl group, and 2% aqueous solution And may have a viscosity of 100 to 200 mPa 占 퐏, preferably 120 to 180 mPa 占 퐏, and more preferably 140 to 160 mPa 占 퐏.

When the viscosity of the cellulosic material is less than 100 mPa.s, the viscosity is too low to produce a polymer by suspension polymerization, the dispersion efficiency is lowered. As the average particle size of the polymer to be produced becomes larger and the inner pore size of the polymer becomes smaller, The reduction rate of the monomer may be slowed and the quality of the protrusions of the polymer to be produced may be deteriorated. If it exceeds 200 mPa · s, the polymerization stability may be lowered and the internal porosity The problem that the rate of decrease of the residual monomer is slowed and the quality of the protrusion of the polymer to be produced deteriorate may occur.

On the other hand, in the example of the present invention, in the case of the vinyl alcohol resin which can be contained as a protective colloid auxiliary in addition to the cellulose-based material, the hydration degree is 30% to 98%, and the surface tension of the prepolymerized mixture is 44 mN / m or less (Vinyl alcohol resin) having a degree of hydration of more than 60% but not more than 98% (high water-solubility resin), and the like. And a vinyl alcohol-based resin having a degree of hydration of 30% to 60% (low hydration resin), and more specifically, a mixture of a vinyl alcohol-based resin having a hydration degree of more than 75% and not more than 98% (Hydration degree resin) having a hydration degree of not less than 60% and not more than 75% and a vinyl alcohol-based resin having a hydration degree of 30% to 60% (low hydration degree resin) ≪ / RTI > Here, the vinyl alcohol resin may have a different surface tension depending on the degree of hydration. Specifically, the vinyl alcohol resin having a relatively high hydration degree may have a relatively high surface tension, and may have a relatively low degree of hydration. The alcohol-based resin may have a relatively low surface tension value. For example, the protective colloid preparation according to an embodiment of the present invention is a polyvinyl alcohol resin having a hydration degree of not less than 75% but not more than 98% and a surface tension of not less than 44 mN / m, a hydration degree of not less than 60% and not more than 75% A polyvinyl alcohol resin having a surface tension of 40 mN / m or more and less than 44 mN / m, preferably 40 mN / m to 42 mN / m, and a polyvinyl alcohol resin having a hydration degree of 30% to 60% and a surface tension of 40 mN / And less than 44 mN / m, preferably 40 mN / m to 42 mN / m.

Wherein the content of each of the vinyl alcohol based resins is 0.01 to 0.06 parts by weight of a vinyl alcohol based resin having a hydration degree of more than 75% and not more than 98% based on 100 parts by weight of the vinyl chloride type monomer, 0.01 to 0.06 parts by weight of a resin, and 0.005 to 0.05 parts by weight of a vinyl alcohol resin having a degree of hydration of 30% to 60%.

Specifically, in the protective colloid composition according to one embodiment of the present invention, the vinyl alcohol-based resin has a degree of hydration of 0.01 to 0.06 parts by weight based on 100 parts by weight of the vinyl chloride-based monomer in an amount of more than 75% but not more than 98% a surface tension of 40 mN / m or more and less than 44 mN / m, preferably 40 mN / m to 42 mN / m, and a surface tension of 40 mN / m vinyl alcohol-based resin; And 0.005 to 0.05 parts by weight of a vinyl alcohol-based resin having a degree of hydration of 30% to 60% and a surface tension of 40 mN / m or more and less than 44 mN / m, preferably 40 mN / m to 42 mN / Or mixtures thereof.

The unsaturated organic acid polymer may include an acrylic acid polymer, a methacrylic acid polymer, an itaconic acid polymer, a fumaric acid polymer, a maleic acid polymer, or a succinic acid polymer, among these. Any one or a mixture of two or more may be used.

The suspension polymerization according to an embodiment of the present invention 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, The number average degree of polymerization of the vinyl polymer is reduced. Further, according to one embodiment of the present invention, the plasticizer absorption rate and the projection quality of the polymer produced at an appropriate polymerization temperature can be improved. 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 at a temperature of 50 to 65 캜, more preferably at 53 to 60 캜.

Particularly, in the suspension polymerization, it is preferable that the internal temperature of the reactor at the time of introducing the polymerization initiator is 2 to 5 ° C or higher than the ordinary polymerization initiation temperature, in particular, the polymerization initiation temperature.

According to an embodiment of the present invention, the polymerized water may be a polymerization solvent, and various types of polymerized water such as distilled water or deionized water may be used, and deionized water may be preferably used. The temperature of the polymerization water may be appropriately selected in consideration of the temperature at which suspension polymerization is carried out. The polymerization water may be appropriately used depending on the polymerization conditions. For example, the polymerization water may be used in an amount of not less than 70 parts by weight based on 100 parts by weight of the vinyl chloride monomer, Specifically, it may be used in an amount of 70 to 120 parts by weight.

The polymerization initiator may be used in an amount of 0.02 part by weight to 0.2 part by weight based on 100 parts by weight of the vinyl chloride monomer used for polymerization. Specifically, the polymerization initiator may be used in an amount of 0.03 parts by weight to 0.12 parts by weight based on 100 parts by weight of the vinyl chloride monomer. If the content of the polymerization initiator is less than 0.02 parts by weight, the polymerization reaction time may become longer, the conversion to vinyl chloride polymer may be lowered, and the productivity may be lowered. If the content is more than 0.2 parts by weight, There is a fear of remaining in the vinyl chloride-based polymer finally produced, which may deteriorate the physical properties, particularly the thermal stability, of the polymer.

Examples of the polymerization initiator include, but are not limited to, diacyl peroxides such as dicumyl peroxide, dipentyl peroxide, di-3,5,5-trimethylhexanoyl peroxide and diaryl peroxide, di Butyl peroxydecanoate, isopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, cumyl peroxydicarbonate and the like, t-butyl peroxyneodecanoate, Oxime neoheptanoate, t-amyl peroxyneodecanoate, cumyl peroxyneodecanoate, cumyl peroxyneoheptanoate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, etc. Azo compounds such as azobis-2,4-dimethylvaleronitrile, and sulfates such as potassium persulfate and ammonium persulfate, and the like, and they may be used alone or in combination of two or more thereof It can be used and, preferably di-2-ethylhexyl peroxydicarbonate, cumyl peroxydicarbonate, a t- butyl peroxy neo-decanoic noise agent or a mixture thereof may be used.

The method for producing a vinyl chloride polymer according to an embodiment of the present invention may include stirring the reaction mixture prepared above, and suspension polymerization may 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, the initial agitation speed may be greater than 180 to less than 220 rpm, preferably 190 to 210 rpm, more preferably 195 to 205 rpm.

Further, the method for producing a vinyl chloride polymer according to an embodiment of the present invention may further comprise, after completion of the polymerization, separating and recovering unreacted monomers and products, respectively.

At this time, the suspension polymerization can be terminated by introducing the reaction termination, and the termination time can be set at a time when the pressure in the reactor is 6 kg / cm ² to 8 kg / cm ² (or when the polymerization conversion rate exceeds 85% ). ≪ / RTI >

The reaction termination is not particularly limited, but may be, for example, a phenol compound, an amine compound, a nitrile compound, a sulfur compound or the like. Specifically, the above-mentioned reaction termination is carried out in the presence of triethylene glycol-bis-3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate, hydroquinone, p-methoxyphenol, N-octadecyl-3- (4-hydroxy-3,5-di-t-butylphenyl) propionate, 2,5-di-t-butylhydroquinone, (6-t-butyl-m-cresol), tocopherol, and the like, phenol compounds such as N, N'- Amine compounds such as N, N'-diphenyl-p-phenylenediamine and 4,4'-bis (dimethylbenzyl) diphenylamine, 2-phenylnitronylnitroxide, 3- 3-imidazoline nitroxide, 4-hydroxy-2,2 ', 6,6'-tetramethyl-piperidine-1-oxyl, -tetramethyl-piperidine-1-oxyl), dodecyl mercaptan, sulfur compounds such as 1,2-diphenyl-2-thiol, triphenyl phosphite, Based compound, such as triethyleneglycol-bis-3- (3 (3) -tetrahydroglycerol, triethylenetetraminephosphite, triethylenetetraminephosphite, triethylenetetraminephosphate, 4-hydroxy-5-methylphenyl) propionate, 4-hydroxy-2,2 ', 6,6'-tetramethyl-piperidine- 2 ', 6,6'-tetramethyl-piperidine-1-oxyl) or mixtures thereof.

The vinyl chloride polymer produced by the termination of the polymerization may be in the form of a slurry, and the slurry may be prepared in the form of a final vinyl chloride polymer by removing moisture with a fluidized bed dryer under ordinary reaction conditions.

In addition to the above-described active ingredients, additives such as polymerization regulators, chain transfer agents, pH adjusters, antioxidants, crosslinking agents, antistatic agents, anti-scale agents and surfactants may be further added to the suspension polymerization. Is not particularly limited and can be used in the usual kinds and contents known in the art. The additive may be added at any time of the suspension polymerization, during polymerization or after polymerization, and may be added all at once or continuously added.

As the reactor used in the present invention, there is no particular limitation on the shape of the stirring device such as the stirrer and the baffle, and a stirring device generally used for suspension polymerization of the vinyl chloride polymer may be used. and as a specific example, a stirrer may be a paddle, a pitched paddle, a bloomers gin, a pauldoramari, a turbine, a propeller propeller, and the like, or an agitator combined with two or more agitating blades may be used. As the baffle, a plate type, a cylindrical type, a D type, a loop type, a finger type, or the like can be used.

The polymer produced according to the preparation method of the present invention may have a concentration of unreacted residual monomer in the polymer of 250 ppm or less at 80 ° C for 30 minutes, or 70 ppm or less after 60 minutes. The concentration of the residual monomer was measured in HS-GC / MSD at 100 ° C / 30 min / 20 ml SIM mode using a forced circulation oven at 80 ° C and 1 g at 30 min intervals. The volatile organic compounds As shown in Fig.

The vinyl chloride polymer produced according to one embodiment of the present invention is excellent in plasticizer absorption performance, and therefore, the quality of the processed product can be improved due to the remarkable improvement in the quality of the protrusions, and the inner void of the polymer is developed, The recovery efficiency of the residual monomer is improved and the content of the residual monomer acting as the volatile organic compound is very low, so that there is a positive effect on the environment. Further, since the recovery efficiency of the residual monomer is improved, the residual monomers in the polymer can be easily removed with a relatively low energy and a low cost, so that it is possible to economically increase the production process of the vinyl chloride polymer.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples. However, the following examples and experimental examples are provided for illustrating the present invention, and the scope of the present invention is not limited thereto.

Example 1

390 kg of deionized water was introduced into a 1 m ³ internal volume reactor having a reflux condenser and 160 g of polyvinyl alcohol having a degree of hydration of 88% and a surface tension of 46.2 mN / m at 25 ° C in 0.2% aqueous solution, 92% of a polyvinyl alcohol having a surface tension of 40.4 mN / m at 25 DEG C and a surface tension of 40.4 mN / m at 25 DEG C, a polyvinyl alcohol having a hydration degree of 55% and a surface tension of 40.6 mN / m at 25 DEG C of 0.2% , 30 g of a 2% aqueous solution of hydroxypropylmethylcellulose having a viscosity of 150 mPa 20 at 20 캜 was charged into the reactor in a batch so that the surface tension of the polymerization mixture solution was 43.4 mN / m. Thereafter, 300 kg of vinyl chloride monomer was added, 30 g of di-2-ethylhexyl peroxydicarbonate and 120 g of t-butyl peroxyneodecanonate were added, and the reaction was allowed to proceed while maintaining the polymerization reaction temperature at 58 ° C . When the polymerization reactor pressure reached 6.3 kg / cm ² , 15 g of 4-hydroxy-2,2,6,6-tetramethyl-piperidine-1-oxyl as the reaction terminator and 15 g of triethylene glycol- - (3-t-butyl-4-hydroxy-5-methylphenyl) propionate was added and the unreacted monomer was recovered. The moisture content of the resin slurry was minimized through a stripping process and a dewatering process. The slurry thus obtained was dried in a fluid bed drier at a temperature of 60 캜 to obtain a vinyl chloride polymer.

Example 2

84% polyvinyl alcohol having a surface tension of 46.2 mN / m and a water content of 72% at 25 DEG C at 25 DEG C and a surface tension of 40.4 mN / m at 25 DEG C of 25% 92 g of polyvinyl alcohol having an alcohol concentration of 110 g and a degree of hydration of 55% and having a surface tension of 40.6 mN / m at 25 DEG C of 0.2% aqueous solution, 2% aqueous solution of hydroxypropylmethylcellulose having a viscosity of 150 mPa.s at 20 DEG C 21 g were charged into the reactor in a batch to adjust the surface tension of the polymerization mixture solution to 42.8 mN / m.

Example 3

60 g of polyvinyl alcohol having a surface tension of 46.2 mN / m and a hydration degree of 72% at 25 ° C at 25 ° C. and a surface tension of 40.4 mN / m at 25 ° C. at 25 ° C. 58 g of polyvinyl alcohol having an alcohol content of 94 g and a degree of hydration of 55% and a 0.2% aqueous solution having a surface tension of 40.6 mN / m at 25 DEG C, 2% aqueous solution of hydroxypropylmethylcellulose having a viscosity of 150 mPa.s at 20 DEG C 20 g were charged into the reactor in a batch to adjust the surface tension of the polymerization mixture solution to 43.1 mN / m, followed by conducting polymerization at 64 ° C.

Example 4

40 g of polyvinyl alcohol having a surface tension of 46.2 mN / m and a hydration degree of 72% at 25 DEG C at 25 DEG C and a surface tension of 40.4 mN / m at 25 DEG C at 25 DEG C 62 g of polyvinyl alcohol having 110 g of alcohol and 55% of hydration and having a surface tension of 40.6 mN / m in 0.2% aqueous solution at 25 DEG C, 2 g of a 2% aqueous solution of hydroxypropylmethylcellulose having a viscosity of 150 mPa.s at 20 DEG C 20 g of polyvinyl alcohol was added all at once into the reactor to adjust the surface tension of the polymerization mixture solution to 43.8 mN / m, and polymerization was then carried out at 64 ° C.

Example 5

120 g of polyvinyl alcohol having a hydration degree of 80% and a surface tension of 45.8 mN / m at 0.2% aqueous solution at 25 DEG C, a polyvinyl alcohol having a hydration degree of 72% and a surface tension of 40.4 mN / m at 25 DEG C at 25 DEG C 45 g of polyvinyl alcohol having an alcohol content of 112 g and a degree of hydration of 40% and a 0.2% aqueous solution having a surface tension of 41.1 mN / m at 25 DEG C, 2% aqueous solution of hydroxypropylmethylcellulose having a viscosity of 165 mPa.s at 20 DEG C 28 g was added to the reactor in a batch to adjust the surface tension of the polymerization mixture solution to 43.2 mN / m, and then the polymerization was carried out in the same manner as in Example 1.

Comparative Example 1

The polyvinyl alcohol having a hydration degree of 88% and having a surface tension of 48.2 mN / m of 0.2% aqueous solution at 25 캜 and having a hydration degree of 72% and a surface tension of 42.1 mN / m at 25 캜 of 25% 25 g of polyvinyl alcohol having 92 g of alcohol and 55% of hydration at 25 DEG C and having a surface tension of 42.3 mN / m in 0.2% aqueous solution, 2% aqueous solution of hydroxypropylmethyl cellulose having a viscosity of 150 mPa.s at 20 DEG C Was added to the reactor in a batch so that the surface tension of the mixed solution was 45.5 mN / m.

Comparative Example 2

84% polyvinyl alcohol having a surface tension of 48.2 mN / m and a water content of 72% at 25 DEG C at 25 DEG C and having a surface tension of 42.1 mN / m at 25 DEG C at 25 DEG C 92 g of polyvinyl alcohol having a water content of 55% and an aqueous alcohol content of 25% at 25 DEG C and having a surface tension of 42.3 mN / m at 25 DEG C, 2% aqueous solution of hydroxypropylmethylcellulose having a viscosity of 150 mPa.s at 20 DEG C Was added to the reactor in a batch so that the surface tension of the mixed solution was 44.3 mN / m.

Comparative Example 3

60 g of polyvinyl alcohol having a surface tension of 48.2 mN / m and a water content of 72% at 25 DEG C at 25 DEG C and a surface tension of 42.1 mN / m at 25 DEG C at 25 DEG C 58 g of polyvinyl alcohol having an alcohol content of 94 g and a degree of hydration of 55% and having a surface tension of 42.3 mN / m at 25 DEG C in a 0.2% aqueous solution, 2% aqueous solution of hydroxypropylmethylcellulose having a viscosity of 150 mPa.s at 20 DEG C Was added to the reactor in a batch to adjust the surface tension of the mixed solution to 44.8 mN / m, and the polymerization was then carried out at 64 ° C.

Comparative Example 4

40 g of polyvinyl alcohol having a surface tension of 48.2 mN / m and a hydration degree of 72% at 25 ° C. at 25 ° C. and a surface tension of 42.1 mN / m at 25 ° C. at 25 ° C. 62 g of polyvinyl alcohol having a water content of 55% and an aqueous alcohol content of 25% at 25 DEG C and a surface tension of 42.3 mN / m at 25 DEG C, 2% aqueous solution of hydroxypropylmethylcellulose having a viscosity of 150 mPa.s at 20 DEG C Was added to the reactor in a batch to adjust the surface tension of the mixture to 45.9 mN / m, and the polymerization was carried out at 64 ° C.

Comparative Example 5

30 g of 2% aqueous solution of hydroxypropylmethylcellulose having a viscosity of 85 mPa 20 at 20 캜 was added all at once to the reactor so that the surface tension of the mixed solution was 43.1 mN / m. .

Comparative Example 6

30 g of 2% aqueous solution of hydroxypropylmethylcellulose having a viscosity of 350 mPa 20 at 20 캜 was added to the reactor in a batch to adjust the surface tension of the mixed solution to 43.7 mN / m.

Comparative Example 7

30 g of water-soluble partially saponified polyvinyl acetate having a viscosity of 150 mPa 20 at 20 캜 in a 2% aqueous solution was added all at once to the reactor so that the surface tension of the mixed solution was 43.4 mN / m. .

Experimental Example 1

The vinyl chloride-based polymers prepared in Examples 1 to 5 and Comparative Examples 1 to 7 were evaluated by the following evaluation items, and the results are shown in the following Table 1 and FIGS.

1) Measurement of plasticizer absorption

Based on ASTM D3367-95, the amount of dioctyl phthalate (DOP) absorbed in the vinyl chloride-based polymer samples prepared in Examples and Comparative Examples was expressed as% by weight with respect to the sample before absorption.

2) Measure the number of fish-eye

100 parts by weight of the vinyl chloride-based polymer prepared in Examples and Production Examples, 45 parts by weight of dioctyl phthalate (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, To prepare a sheet having a thickness of 0.3 mm, and the number of white transparent particles in the sheet was 400 cm ² .

3) Measurement of polymerization degree

Based on ASTM D1 243-49, the degree of polymerization of the vinyl chloride-based polymer prepared in Examples and Comparative Examples was measured.

4) Determination of residual unreacted monomer content

The vinyl chloride polymer prepared in Examples and Comparative Examples was placed in a forced circulation oven at 80 ° C. and 1 g was taken at intervals of 30 minutes and volatilized from HS-GC / MSD at 100 ° C./30 minutes / 20 ml SIM mode The organic compound (VOC) component was analyzed.

division Example Comparative Example One 2 3 4 5 One 2 3 4 5 6 7 Plasticizer absorption
(weight %) 20.4 24.0 15.9 17.5 20.3 19.1 22.2 14.4 16.0 19.5 19.3 19.8 Number of projections () 7 One 6 2 8 13 8 11 9 9 12 10 Degree of polymerization 1010 1005 805 800 1005 1005 1000 805 805 1005 1000 1005 Residual monomer content
(ppm) 0
(min) 827 874 901 844 857 845 801 833 864 820 853 904 30 180 174 204 197 184 324 411 384 403 294 315 354 60 54 49 63 58 61 144 198 182 195 104 148 174 90 4.47 3.57 5.7 6.99 5.45 35 46 55 42 24 43 58 120 1.57 2.57 2.47 3.41 2.04 11 22 20 15 13 21 27 150 0.94 1.34 1.78 2.41 1.05 2.66 5.36 6.84 4.52 5.14 7.60 8.40 180 0.74 0.88 0.97 1.04 0.86 1.45 2.66 3.94 2.12 3.10 4.88 4.85 210 0.54 0.49 0.60 0.58 0.45 0.97 1.84 2.01 0.99 1.04 2.32 1.08

As shown in Table 1, it can be seen that Examples 1 to 5 are superior in plasticizer uptake to those of Comparative Examples 1 to 7, and it can be confirmed that the quality of the projection of the polymer is improved from the small number of projections, It can be confirmed that the recovery efficiency of the residual monomer is excellent because the residual monomer is remarkably reduced even in a relatively short time because the rate of decrease of the monomer is high.

Specifically, Comparative Examples 1 and 2, 3 and 4 show that although the surface tension of the polymerization mixture used in the preparation of the polymer is more than 44 mN / m and the viscosity of the cellulose contained in the protective colloid preparation is similar to the present invention It can be confirmed that the plasticizer absorption amount is decreased and the number of projections is increased and the projection quality deteriorates as compared with Examples 1 and 2, 3 and 4, which are polymers produced at the same polymerization temperature, and the decrease in residual monomer in the polymer is also slow, It can be confirmed that the recovery efficiency of the residual monomer is lowered.

In addition, in Comparative Example 5, the viscosity of the cellulose contained in the protective colloid preparation was lower than that in Examples, and although the surface tension of the polymerization mixture used in the production of the polymer was similar to that of the present invention, the number of projections was increased, And it can be confirmed that the average pore size of the polymer produced in the polymerization mechanism becomes larger and the pore size of the polymer becomes smaller and the rate of decrease of the residual monomer is lowered and the recovery efficiency of the residual monomer is lowered.

As in Comparative Examples 6 and 7, the viscosity of the cellulose contained in the protective colloid preparation was higher than that in the Examples, or different formulations were used without using cellulose. In Comparative Examples 6 and 7, Although the surface tension of the polymerization mixture used in the preparation is similar to that of the present invention, the number of projections is increased and the quality of the projections is deteriorated. Particularly, the polymerization stability is lowered and the pores in the polymer are blocked due to particle aggregation, Is remarkably lower than that of the examples and the recovery efficiency of the residual monomers in the polymer is lowered.

In addition, referring to FIGS. 1 to 4, which graphically illustrate the amount of residual monomer reduction in Examples and Comparative Examples, comparison of the rate of decrease of residual monomer can be made easier.

Referring to FIGS. 1 to 4, it can be seen that the slopes of the decreasing graphs of Examples 1 to 4 are abruptly higher than those of Comparative Examples 1 to 7, and the rate of reduction of the residual monomers of the vinyl chloride- And the faster rate of reduction of the residual monomer means that the recovery efficiency of unreacted residual monomer in the polymer is excellent.

Thus, by satisfying the requirement that the surface tension of the polymerization mixture is adjusted to 44 mN / m or less and that the viscosity of the protective colloid composition is 100 to 200 mPa · s simultaneously, the plasticizer absorption is excellent and the projection quality is improved And the inner voids in the polymer are developed. As a result, the rate of reduction of the residual monomers is increased, and thus it is possible to produce a vinyl chloride polymer having excellent recovery efficiency of the residual monomers.

Claims (12)

Polymerizing the vinyl chloride-based monomer in the presence of the polymerization mixture to prepare a vinyl chloride-based polymer,
Wherein the polymerization mixture comprises polymerized water, a polymerization initiator and a protective colloid assistant, wherein the polymerization mixture has a surface tension of 44 mN / m or less,
Wherein the protective colloid assistant comprises a vinyl alcohol-based resin and a cellulose-based material having a viscosity of from 2 to 100 mPa · s at 20 ° C in a 2% aqueous solution.
The method according to claim 1,
Wherein the polymerization mixture has a surface tension of 42 mN / m to 44 mN / m.
The method according to claim 1,
Wherein the cellulose-based material has a viscosity of 2% aqueous solution at 140 ° C to 160 mPa · s at 20 ° C.
The method according to claim 1,
Wherein the cellulose-based material is contained in an amount of 0.001 to 0.1 part by weight based on 100 parts by weight of the vinyl chloride-based monomer.
The method according to claim 1,
Wherein the cellulose-based material is contained in an amount of 0.001 to 0.02 part by weight based on 100 parts by weight of the vinyl chloride-based monomer.
The method according to claim 1,
Wherein the cellulose-based material comprises at least one selected from the group consisting of methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl methylcellulose.
The method according to claim 1,
Wherein the vinyl alcohol-based resin comprises a mixture of two or more vinyl alcohol-based resins having different degrees of hydration and surface tension.
The method according to claim 1,
Wherein the vinyl alcohol resin has a degree of hydration of 76% to 98% and a surface tension of 44 mN / m or more; A vinyl alcohol-based resin having a hydration degree of 61% to 75% and a surface tension of 40 mN / m or more and less than 44 mN / m; And a vinyl alcohol-based resin having a hydration degree of 30% to 60% and a surface tension of 40 mN / m or more and less than 44 mN / m; ≪ / RTI > and mixtures thereof.
The method according to claim 1,
Wherein the vinyl alcohol resin has a hydration degree of more than 75% to 98% and a surface tension of 44 mN / m or more; A vinyl alcohol-based resin having a hydration degree of more than 60% but not more than 75% and a surface tension of 40 mN / m to 42 mN / m; And a vinyl alcohol-based resin having a hydration degree of 30% to 60% and a surface tension of 40 mN / m to 42 mN / m; ≪ / RTI > and mixtures thereof.
The method according to claim 1,
Based on 100 parts by weight of the vinyl chloride-based monomer,
0.01 to 0.06 parts by weight of a vinyl alcohol-based resin having a degree of hydration of more than 75% to 98% and a surface tension of 44 mN / m or more;
0.01 to 0.06 parts by weight of a vinyl alcohol-based resin having a degree of hydration of more than 60% but not more than 75% and a surface tension of not less than 40 mN / m and not more than 44 mN / m; And
And 0.005 to 0.05 part by weight of a vinyl alcohol-based resin having a degree of hydration of 30% to 60% and a surface tension of 40 mN / m or more and less than 44 mN / m.
The method according to claim 1,
Wherein the suspension polymerization is carried out at 30 캜 to 80 캜.
The method according to claim 1,
Wherein the suspension polymerization is carried out at 53 캜 to 60 캜.

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