KR20220009686A - Method for preparing vinylchloride-based polymer - Google Patents

Abstract

The present invention relates to a method for preparing a vinylchloride-based polymer which comprises the following steps of adding a C_4 to C_20 linear alkyl alcohol and a first vinyl chloride-based monomer into a reactor and initiating suspension polymerization; and adding a second vinyl chloride-based monomer to the reactor and performing suspension polymerization when the polymerization conversion rate reaches 10 to 40%, wherein the C_4 to C_20 linear alkyl alcohol is added in an amount of 1 to 5 parts by weight based on 100 parts by weight of the first vinyl chloride-based monomer.

Description

Method for producing a vinyl chloride-based polymer {METHOD FOR PREPARING VINYLCHLORIDE-BASED POLYMER}

The present invention relates to a method for producing a vinyl chloride-based polymer, and more particularly, to a method for producing a vinyl chloride-based polymer having excellent productivity and processability.

The vinyl chloride-based polymer is a polymer containing 50% or more of vinyl chloride monomer units, and it is easy to control physical properties and has excellent economic efficiency. In addition, vinyl chloride-based polymers can be used to manufacture molded articles with excellent mechanical properties, weather resistance and chemical resistance, and are widely used in various fields.

Recently, as vinyl chloride-based polymers are widely used as raw materials for building materials and pipes, it is required to shorten the melting time and improve foamability of the vinyl chloride-based polymers.

On the other hand, in order to increase the productivity of the vinyl chloride-based polymer, JP2002-128805A discloses a vinyl chloride-based polymer prepared by fine suspension polymerization while dividing or continuously adding a vinyl chloride-based monomer after polymerization is started. However, since a vinyl chloride-based polymer having an average particle diameter of 1 to 2 μm is prepared by fine suspension polymerization, it is difficult to prepare a vinyl chloride-based polymer having an average particle diameter of 140 to 150 μm suitable for hard processing. In addition, since the vinyl chloride-based polymer prepared by micro-suspension polymerization is soft, it cannot be applied to the molding process of building materials or finished pipe products, and there is a problem in that thermal stability is lowered due to the emulsifier.

JP2002-128805A

The problem to be solved by the present invention is to provide a method for producing a vinyl chloride-based polymer excellent in productivity and processability.

In order to solve the above problems, the present invention comprises the steps of introducing a C ₄ to C ₂₀ linear alkyl alcohol and a first vinyl chloride-based monomer into a reactor and initiating suspension polymerization; and when the polymerization conversion rate reached 10 to 40%, adding a second vinyl chloride monomer to the reactor and performing suspension polymerization, wherein the C ₄ to C ₂₀ linear alkyl alcohol was mixed with the first vinyl chloride. Provided is a method for producing a vinyl chloride-based polymer in which 1 to 5 parts by weight is added based on 100 parts by weight of the monomer.

The method for producing a vinyl chloride-based polymer according to the present invention not only has excellent productivity, but also shortens the melting time and improves foamability, thereby producing a vinyl chloride-based polymer with improved processability.

Hereinafter, in order to help the understanding of the present invention, it will be described in more detail.

The terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor may properly define the concept of the term in order to best describe his invention. Based on the principle that there is, it should be interpreted as meaning and concept consistent with the technical idea of the present invention.

The term 'vinyl chloride-based monomer' used in the present invention may refer to a pure vinyl chloride monomer or a comonomer copolymerizable with a pure vinyl chloride monomer. The comonomer is ethylene, propylene, vinyl acetate, vinyl propionate, acrylonitrile, methyl vinyl ether, ethyl vinyl ether, acrylic acid, acrylic acid anhydride, methacrylic acid, methacrylic acid anhydride, itaconic acid, itaconic acid anhydride, maleic acid And it may be at least one selected from the group consisting of maleic anhydride.

The terms 'specific examples of the first vinyl chloride-based monomer and the second vinyl chloride-based monomer' used in the present invention may be the same as or different from each other.

As used herein, the term 'linear alkyl' refers to straight-chain or branched-chain alkyl.

The term 'polymerization conversion rate' used in the present invention can be calculated by the following formula.

Polymerization conversion (%) = {(total weight of vinyl chloride monomer added until polymerization is completed)-(total weight of unreacted vinyl chloride monomer at the time polymerization conversion is measured)}/(to end polymerization Total weight of vinyl chloride monomer added until

The term 'number average degree of polymerization' used in the present invention refers to the average number of repeating units in the chain of the vinyl chloride-based polymer, and may be calculated as a ratio of the number average molecular weight to the molecular weight of the repeating unit.

The term 'average particle diameter' used in the present invention is an average particle diameter measured from the angle of light diffracted according to the particle size when the vinyl chloride-based polymer powder passes through a cell using a laser particle meter and It may be a particle size distribution value.

Method for producing vinyl chloride-based polymer

The method for producing a vinyl chloride-based polymer according to an embodiment of the present invention includes _{the steps of: adding a C 4} to C ₂₀ linear alkyl alcohol and a first vinyl chloride-based monomer to a reactor and initiating suspension polymerization; and when the polymerization conversion rate reached 10 to 40%, adding a second vinyl chloride monomer to the reactor and performing suspension polymerization, wherein the C ₄ to C ₂₀ linear alkyl alcohol was mixed with the first vinyl chloride. Based on 100 parts by weight of the system monomer, 1 to 5 parts by weight are added.

Hereinafter, a method for producing a vinyl chloride-based polymer according to an embodiment of the present invention will be described in detail.

1) Initiating suspension polymerization

First, a C ₄ to C ₂₀ linear alcohol and a first vinyl chloride-based monomer are added to the reactor, followed by suspension polymerization.

_{When a C 4} to C ₂₀ linear alcohol used as a dispersing aid in micro-suspension polymerization is used in suspension polymerization, effects that were not realized in micro-suspension polymerization, processability of vinyl chloride-based polymers, specifically, melting of vinyl chloride-based polymers Time can be shortened and foamability can be improved.

However, when C ₃ or less linear alkyl alcohol is added, the foamability of the vinyl chloride-based polymer is reduced. When a C ₂₁ or more linear alkyl alcohol is added, the processability of the vinyl chloride-based polymer is reduced. And, when C ₃ to C ₂₀ cyclic alkyl alcohol is added, the productivity of the vinyl chloride-based polymer is reduced.

The C ₄ to C ₂₀ linear alkyl alcohol is n-butyl alcohol, tert-butyl alcohol, sec-butyl alcohol, n-amyl alcohol, tert-amyl alcohol, n-hexyl alcohol, tert-hexyl alcohol, sec-hexyl alcohol , from the group consisting of 2-ethylhexyl alcohol, n-octyl alcohol, tert-octyl alcohol, n-decyl alcohol, n-lauryl alcohol, tert-lauryl alcohol, n-tetradecyl alcohol, cetyl alcohol and stearyl alcohol. It may be one or more selected from among them, 2-ethylhexyl alcohol, n-lauryl alcohol, and cetyl alcohol are preferable. The cetyl alcohol may be straight-chain or branched-chain cetyl alcohol, and the branched-chain cetyl alcohol may be composed of one branched-chain cetyl alcohol or a combination of various types of branched-chain cetyl alcohol.

The C ₄ to C ₂₀ linear alkyl alcohol may be added in an amount of 1 to 5 parts by weight, preferably 2.5 to 4.5 parts by weight, based on 100 parts by weight of the first vinyl chloride-based monomer. When the input is less than the above-mentioned range, the effect of improving processability is insignificant. When the input exceeds the above range, during processing of the vinyl chloride-based polymer, the vinyl chloride-based polymer is adhered to the surface of the processing machine, and the surface properties of the vinyl chloride-based polymer molded article are deteriorated.

The suspension polymerization may be carried out in the presence of an initiator, a dispersant and an aqueous solvent.

The initiator is dicumyl peroxide, dipentyl peroxide, di(3,5,5-trimethylhexanoyl)peroxide, dilauroyl peroxide, diisopropyl peroxydicarbonate, di-sec-butylperoxydicarbonate , di (2-ethylhexyl) peroxy dicarbonate, t-butyl peroxy neodecanoate, t-butyl peroxy neoheptanoate, t-amyl peroxy neodecanoate, cumyl peroxy neodecanoate, selected from the group consisting of cumyl peroxy neoheptanoate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, azobis-2,4-dimethylvaleronitrile, potassium persulfate and ammonium persulfate There may be more than one type.

The content of the initiator may be 0.03 to 0.15 parts by weight, preferably 0.05 to 0.12 parts by weight, more preferably 0.06 to 0.1 parts by weight based on 100 parts by weight of the total of the first vinyl chloride-based monomer and the second vinyl chloride-based monomer. have. When the above-mentioned range is satisfied, polymerization stability may be improved.

The dispersing agent is polyvinyl alcohol, polyvinyl alcohol partially saponified with oil, polyacrylic acid, a copolymer of vinyl acetate and maleic anhydride, hydroxypropyl methylcellulose, gelatin, calcium phosphate, hydroxyapatite, sorbitan monolaurate, It may be at least one selected from the group consisting of sorbitan trioleate, polyoxyethylene, sodium lauryl sulfate, sodium dodecylbenzenesulfonate and sodium dioctylsulfosuccinate.

The content of the dispersant may be 0.03 to 0.2 parts by weight, preferably 0.05 to 0.15 parts by weight, more preferably 0.06 to 0.12 parts by weight based on 100 parts by weight of the total of the first vinyl chloride-based monomer and the second vinyl chloride-based monomer. have. When the above-described range is satisfied, polymerization stability is improved, and unreacted monomers can be easily recovered after polymerization is completed, thereby improving productivity.

The aqueous solvent may be at least one selected from the group consisting of deionized water and pure water.

2) Suspension polymerization

Then, when the polymerization conversion reaches 10 to 40%, a second vinyl chloride-based monomer is added to the reactor and suspension polymerization is carried out.

When the polymerization conversion reaches 10 to 40%, preferably, when the polymerization conversion reaches 15 to 30%, when the second vinyl chloride-based monomer is added to the reactor, polymerization stability can be improved. However, if the second vinyl chloride-based monomer is added at a time point less than the above-mentioned range or at a time point exceeding the above-mentioned range, the final polymerization conversion rate is lowered to lower productivity, and processability may be significantly reduced.

For stable productivity, it is preferable to continuously input the second vinyl chloride-based monomer.

The time when the continuous input of the second vinyl chloride-based monomer is terminated is a time when the polymerization conversion is 80% or less, preferably a time when the polymerization conversion is 60 to 80%, more preferably a time when the polymerization conversion is 65 to 75% It may be a time point. . When the above conditions are satisfied, high productivity can be achieved while stably producing a vinyl chloride-based polymer.

Meanwhile, the second vinyl chloride-based monomer may be added in an amount of 5 to 30 parts by weight, preferably 10 to 25 parts by weight, based on 100 parts by weight of the first vinyl chloride-based monomer. When the above-mentioned range is satisfied, a vinyl chloride-based copolymer having excellent processability and foamability can be prepared.

The suspension polymerization may be terminated when a pressure difference of 1.0 kg/cm 2 or more occurs compared to the pressure of the polymerization reactor at the start of the suspension polymerization.

The vinyl chloride-based polymer prepared by the method for producing a vinyl chloride-based polymer according to an embodiment of the present invention may have a number average degree of polymerization of 950 to 1,050, preferably 990 to 1,010. And, the average particle diameter of the vinyl chloride-based polymer may be 140 to 170 ㎛, preferably 145 to 165 ㎛, more preferably 150 to 160 ㎛.

A composition comprising a vinyl chloride polymer prepared by the method for producing a vinyl chloride polymer according to an embodiment of the present invention is an additive comprising at least one selected from the group consisting of a stabilizer, a processing aid, an impact modifier, and a lubricant. may include

The additive may be included in an amount of 1 to 15 parts by weight, preferably 2 to 13 parts by weight, based on 100 parts by weight of the vinyl chloride-based polymer composite.

The stabilizer is a material that prevents coloring and decomposition by increasing stability to heat, and may be a metal-based stabilizer or an organic acid metal salt stabilizer. The metal-based stabilizer may be one or two selected from the group consisting of a lead-based stabilizer, an (organic) tin-based stabilizer, a cadmium-based stabilizer, and a barium-based stabilizer. The organic acid metal salt may be a metal salt of carboxylic acid, organic phosphoric acid, or phenols. The carboxylic acid is caproic acid, caprylic acid, pelargonic acid, 2-ethylhexyl acid, capric acid, neodecanoic acid, undecylenic acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, 12- Hydroxystearic acid, chlorostearic acid, 12-ketostearic acid, phenylstearic acid, ricinolic acid, linoleic acid, linolenic acid, oleic acid, arachinic acid, behenic acid, erucic acid, brassic acid, pseudoacid, resin fatty acid, palm oil fatty acid, tung oil fatty acid, 1 selected from the group consisting of soybean oil fatty acid, cottonseed oil fatty acid, benzoic acid, pt-butylbenzoic acid, ethylbenzoic acid, isopropylbenzoic acid, toluic acid, xylyl acid, salicylic acid, 5-t-octylsalicylic acid, naphthenic acid and cyclohexacarboxylic acid species or two or more species. The organic phosphoric acid is monooctyl phosphoric acid, dioctyl phosphoric acid, monododecyl phosphoric acid, didodecyl phosphoric acid, monooctadecyl phosphoric acid, dioctadecyl phosphoric acid, mono(nonylphenyl) phosphoric acid, di(nonylphenyl) phosphoric acid, nonylphenyl phosphonate. It may be one or two or more selected from the group consisting of esters, phosphonate nonylphenyl esters, and phosphonic acid stearyl esters. The phenols may be at least one selected from the group consisting of phenol, cresol, ethylphenol, cyclohexylphenol, nonylphenol, and dodecylphenol. The metal salt may be a neutral salt, an acid salt, a basic salt, or an overbased complex.

The processing aid is a material that promotes the gelation of the vinyl chloride-based polymer, and includes an alkyl methacrylate-based homopolymer or copolymer such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate; alkyl methacrylate/alkyl acrylate copolymers; copolymers of the above alkyl methacrylates with aromatic vinyl compounds such as styrene, α-methylstyrene, and vinyltoluene; and copolymers of alkyl methacrylate and vinyl cyan compounds such as acrylonitrile and methacrylonitrile. The processing aid may be used alone or in a mixture of two or more.

The impact modifier is a material for reinforcing impact resistance by giving elasticity to the vinyl chloride polymer, and is a MBS (Methyl Methacrylate-Butadiene-Styrene)-based polymer, a chlorinated polyethylene-based copolymer, an ethylene vinyl acetate-based polymer, an acrylic polymer, and a butadiene-based polymer. It may be at least one selected from the group consisting of polymers.

The lubricant is a material for improving the processability and interfacial properties of the vinyl chloride-based polymer, and includes hydrocarbon lubricants such as low molecular weight wax, paraffin wax, polyethylene wax, chlorinated hydrocarbon, and fluorocarbon; natural wax-based lubricants such as carnauba wax and candelilla wax; fatty acid-based lubricants such as higher fatty acids such as lauric acid, stearic acid and behenic acid, or oxy fatty acids such as hydroxystearic acid; aliphatic amide compounds such as stearylamide, laurylamide and oleylamide or aliphatic amide lubricants such as alkylenebisaliphatic amide such as methylenebisstearylamide and ethylenebisstearylamide; Fatty acid monohydric alcohol ester compounds such as stearyl stearate, butyl stearate, and distearyl phthalate, or glycerin tristearate, sorbitan tristearate, pentaerythritol tetrastearate, dipentaerythritol hexastearate, polyglycerin Fatty acid polyhydric alcohol ester compounds such as polyricinolate and hydrogenated castor oil, or fatty acid alcohol esters such as monohydric fatty acids such as adipic acid/stearic acid esters of dipentaerythritol, and complex ester compounds of polybasic organic acids and polyhydric alcohols lubricating agent; aliphatic alcohol lubricants such as stearyl alcohol, lauryl alcohol and palmityl alcohol; metal soaps; montanic acid lubricants such as partially saponified montanic acid esters; acrylic lubricant; and silicone oil. The lubricant may be used alone or as a mixture of two or more.

Hereinafter, preferred embodiments are presented to aid the understanding of the present invention, but it is obvious to those skilled in the art that various changes and modifications are possible within the scope of the present description and the technical spirit of the present invention. It is natural that such variations and modifications fall within the scope of the appended claims.

Examples and Comparative Examples

Examples 1 to 8, Comparative Examples 1 to 8

A 1 m polymerization reactor, a stirrer located inside the polymerization reactor, a reflux condenser connected to the polymerization reactor and controlling the polymerization temperature, and a vinyl chloride recovery pipe connected to the reflux condenser and discharging unreacted vinyl chloride monomer A vinyl chloride-based polymer was prepared using a polymerization apparatus including

Specifically, 100 parts by weight of vinyl chloride monomer, 0.06 parts by weight of t-butyl peroxy neodecanoate, 120 parts by weight of deionized water, 0.08 parts by weight of polyvinyl alcohol, C _{4 described in Tables 1 to 3 in the polymerization reactor} To C ₂₀ A linear alkyl alcohol was added. A vacuum was applied to the polymerization reactor, and the pressure was increased until the internal pressure reached 8.2 kg/cm 2 , and the temperature was raised to 58° C. while stirring. When the temperature of the polymerization reactor reaches 58 ° C and the polymerization conversion rate shown in Tables 1 to 3 is reached, 20 parts by weight of the vinyl chloride monomer at a constant rate, continuously for the time shown in Tables 1 to 3 It polymerized while adding tea. When the internal pressure of the polymerization reactor reached 7.0 kg/cm 2 , polymerization was terminated.

Then, the polymerization reactor was cooled, and the unsaturated monomer and vinyl chloride polymer slurry were recovered. Then, the vinyl chloride polymer slurry was stripped and dehydrated, followed by hot air drying in a fluidized bed dryer. The dried vinyl chloride-based polymer was selected to select the vinyl chloride-based polymer.

Comparative Example 9

0.8 parts by weight of sodium lauryl sulfate, 3 parts by weight of n-lauryl alcohol, and 60 parts by weight of deionized water were added to a homogenizer of 0.2 m and stirred. Then, 3 parts by weight of di-2-ethylhexyl peroxycarbonate and 100 parts by weight of a vinyl chloride monomer were added to the homogenizer and stirred to prepare a reaction product. Then, the total pressure of the homogenizer was set to 98.4 kg/cm 2 (1,400 psi), and the reactants were distributed in a weight ratio of 50:50 to the front and rear ends of the homogenizer and operated.

Then, the reactant was transferred to a polymerization reactor of 1 m 3 , and the internal temperature of the polymerization reactor was adjusted to 58° C. and polymerization was carried out. Then, the unreacted monomer was recovered to prepare a vinyl chloride-based polymer latex. The vinyl chloride-based polymer latex was spray-dried to prepare a vinyl chloride-based polymer powder.

Experimental Example 1: Productivity evaluation

After polymerization of the vinyl chloride-based polymers of Examples and Comparative Examples, the weight of the recovered vinyl chloride monomer was measured, and substituted into the following formula to calculate the final polymerization conversion rate. And, the results are described in Tables 1 to 3 below.

Final polymerization conversion (%) = {(total weight of vinyl chloride monomer added until polymerization is complete)-(total weight of vinyl chloride monomer recovered after polymerization is complete)}/(chloride added until polymerization is complete) Total weight of vinyl monomer) × 100

Experimental Example 2: Processability Evaluation 1

100 parts by weight of the vinyl chloride-based polymer of Examples and Comparative Examples and 0.1 parts by weight of a calcium-based thermal stabilizer (calcium stearate) were mixed to prepare a mixture, and the fusion time of the mixture was measured with a Brabender rheometer. . And, the results are described in Tables 1 to 3 below.

Experimental Example 3: Processability Evaluation 2

100 parts by weight of the vinyl chloride-based polymer of Examples and Comparative Examples, 0.1 parts by weight of a calcium-based thermal stabilizer (calcium stearate), and 0.2 parts by weight of a foaming agent (azo dicarbonamide) were blended, and a sheet (thickness: 0.2 mm) was prepared by a roll mill. After foaming at 180 ° C., the thickness was measured and foamability was measured in the following manner. And, the results are described in Tables 1 to 3 below.

Foamability (%) = (thickness of sheet after foaming)/(thickness of sheet before foaming) × 100

division Example One 2 3 4 5 6 7 8 C ₄ to C ₂₀ linear alkyl alcohol
(parts by weight) 2-ethylhexyl alcohol (C ₈ H ₁₈ O) 3 0 0 0 0 0 0 0 n-lauryl alcohol (C ₁₂ H ₂₆ O) 0 3 0 0 One 2 4 5 straight chain cetyl alcohol (C ₁₆ H ₃₄ O) 0 0 3 0 0 0 0 0 Branched cetyl alcohol (C ₁₆ H ₃₄ O) 0 0 0 3 0 0 0 0 suspension polymerization ○ ○ ○ ○ ○ ○ ○ ○ micro-suspension polymerization × × × × × × × × Time of starting the secondary input of vinyl chloride monomer (polymerization conversion rate, %) 20 20 20 20 20 20 20 20 Vinyl chloride monomer continuous input time (hours) 3 3 3 3 3 3 3 3 productivity Final polymerization conversion (%) 85.9 86.4 85.5 85.2 84 85.1 86.2 86 machinability Melting time (sec) 48 45 50 43 50 47 46 47 Effervescent (%) 133 135 131 133 128 132 134 133 Branched cetyl alcohol: from Henkel, Germany

division comparative example One 2 3 4 5 C ₄ to C ₂₀ linear alkyl alcohol
(parts by weight) 2-ethylhexyl alcohol (C ₈ H ₁₈ O) 0 7 0 0 0 n-lauryl alcohol (C ₁₂ H ₂₆ O) 0 0 0.5 0.95 5.05 straight chain cetyl alcohol (C ₁₆ H ₃₄ O) 0 0 0 0 0 Branched cetyl alcohol (C ₁₆ H ₃₄ O) 0 0 0 0 0 suspension polymerization ○ ○ ○ ○ ○ micro-suspension polymerization × × × × × Time of starting the secondary input of vinyl chloride monomer (polymerization conversion rate, %) 20 20 20 20 20 Vinyl chloride monomer continuous input time (hours) 3 3 3 3 3 productivity Final polymerization conversion (%) 82.0 83.5 83.4 83.6 85.8 machinability Melting time (sec) 60 50 56 55 53 Effervescent (%) 115 118 120 122 127 Branched cetyl alcohol: from Henkel, Germany

division comparative example 6 7 8 9 C ₄ to C ₂₀ linear alkyl alcohol
(parts by weight) 2-ethylhexyl alcohol (C ₈ H ₁₈ O) 0 0 0 0 n-lauryl alcohol (C ₁₂ H ₂₆ O) 3 0 0 3 straight chain cetyl alcohol (C ₁₆ H ₃₄ O) 0 0 0 0 Branched cetyl alcohol (C ₁₆ H ₃₄ O) 0 0.5 3 0 suspension polymerization ○ ○ ○ × micro-suspension polymerization × × × ○ Time of starting the secondary input of vinyl chloride monomer (polymerization conversion rate, %) 80 20 80 20 Vinyl chloride monomer continuous input time (hours) 0.7 3 0.7 3 productivity Final polymerization conversion (%) 81.2 83.7 81.5 84 machinability Melting time (sec) 65 52 62 62 Effervescent (%) 122 120 121 124 Branched cetyl alcohol: from Henkel, Germany

Referring to Tables 1 to 3, 2-ethylhexyl alcohol, n-lauryl alcohol, straight-chain cetyl alcohol, and branched-chain cetyl alcohol are added in 1 to 5 parts by weight, and when the polymerization conversion rate is 20%, vinyl chloride Examples 1 to 8, in which the monomer was added secondarily, had a high final polymerization conversion rate, a short melting time, and excellent foamability.

However, Comparative Example 1 in which no alcohol was added had a low final polymerization conversion, a long melting time, and poor foamability.

In Comparative Example 2, in which 7 parts by weight of 2-ethylhexyl alcohol was added, the final polymerization conversion rate was low and foamability was not excellent.

Comparative Examples 3 and 4 in which n-lauryl alcohol was added in 0.5 and 0.95 parts by weight, respectively, had low final polymerization conversion rates, long melting times, and poor foamability.

Comparative Example 5, in which 5.05 parts by weight of n-lauryl alcohol was added, had a high final polymerization conversion rate, but a long melting time and poor foamability.

Comparative Example 6, in which the vinyl chloride monomer was secondarily added at a polymerization conversion rate of 80%, had a low final polymerization conversion rate, a long melting time, and poor foamability.

In Comparative Example 7, in which 0.5 parts by weight of branched-chain cetyl alcohol was added, the final polymerization conversion rate was low, the melting time was long, and the foamability was not excellent.

Comparative Example 8, in which the vinyl chloride monomer was secondarily added at a polymerization conversion rate of 80%, had a low final polymerization conversion rate, a long melting time, and poor foamability.

Comparative Example 9, in which a vinyl chloride-based polymer was prepared by micro-suspension polymerization, had a long melting time and did not have excellent foamability.

Claims (7)

Initiating suspension polymerization by adding C ₄ to C ₂₀ linear alkyl alcohol and a first vinyl chloride-based monomer to the reactor; and
When the polymerization conversion rate reaches 10 to 40%, adding a second vinyl chloride-based monomer to the reactor and performing suspension polymerization,
A method for producing a vinyl chloride polymer in which the C ₄ to C ₂₀ linear alkyl alcohol is added in an amount of 1 to 5 parts by weight based on 100 parts by weight of the first vinyl chloride monomer.
The method according to claim 1,
A method for producing a vinyl chloride polymer in which the C ₄ to C ₂₀ linear alkyl alcohol is added in an amount of 2.5 to 4.5 parts by weight based on 100 parts by weight of the first vinyl chloride monomer.
The method according to claim 1,
The C ₄ to C ₂₀ linear alkyl alcohol is n-butyl alcohol, tert-butyl alcohol, sec-butyl alcohol, n-amyl alcohol, tert-amyl alcohol, n-hexyl alcohol, tert-hexyl alcohol, sec-hexyl alcohol , from the group consisting of 2-ethylhexyl alcohol, n-octyl alcohol, tert-octyl alcohol, n-decyl alcohol, n-lauryl alcohol, tert-lauryl alcohol, n-tetradecyl alcohol, cetyl alcohol and stearyl alcohol. A method for producing a vinyl chloride-based polymer that is one or more selected.
The method according to claim 1,
When the polymerization conversion rate reaches 15 to 30%, the method for producing a vinyl chloride-based polymer by adding the second vinyl chloride-based monomer to the reactor.
The method according to claim 1,
A method for producing a vinyl chloride-based polymer in which the second vinyl chloride-based monomer is continuously added.
The method according to claim 1,
The method for producing a vinyl chloride-based polymer by adding the second vinyl chloride-based monomer in an amount of 5 to 30 parts by weight based on 100 parts by weight of the first vinyl chloride-based monomer.
The method according to claim 1,
The method for producing a vinyl chloride-based polymer, wherein the second vinyl chloride-based monomer is added in an amount of 10 to 25 parts by weight based on 100 parts by weight of the first vinyl chloride-based monomer.