Title of Invention: Method for Producing Vinyl Chloride-Based Polymer
technical field
[One]
[Citation with related applications]
[2]
The present invention claims the benefit of priority based on Korean Patent Application No. 10-2020-0088220 filed on July 16, 2020, and all contents disclosed in the documents of the Korean patent application are incorporated as a part of this specification.
[3]
[Technical field]
[4]
The present invention relates to a method for producing a vinyl chloride-based polymer, and to a method for producing a vinyl chloride-based polymer having improved meltability.
[5]
background
[6]
A vinyl chloride-based polymer prepared by polymerizing a vinyl chloride monomer as a main component is the most widely used synthetic resin among thermoplastic resins.
[7]
The vinyl chloride-based polymer may be prepared by suspension polymerization, emulsion polymerization, and bulk polymerization. Among these, suspension polymerization has a high final polymerization conversion rate, low operating cost, easy recovery of unreacted monomers after polymerization is complete, and easy maintenance due to a small amount of scale accumulation in the polymerization reactor due to the coating system, Mass production is possible.
[8]
On the other hand, in order to process the vinyl chloride-based polymer into a final product, it is necessary to mix it with various additives and proceed with extrusion. At this time, as the melting of the mixture proceeds rapidly, the chains of the vinyl chloride-based polymer are well released to form a strong bond with each other, and the mechanical properties of the final product are increased.
[9]
However, if the melting proceeds slowly, the chain of the vinyl chloride-based polymer cannot be unwound, so migelling particles are formed. can
[10]
Accordingly, research to improve the meltability when mixing the vinyl chloride-based polymer and the additive is continuing.
[11]
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[12]
The problem to be solved by the present invention is to improve the meltability without affecting the thermal stability and polymerization time of the vinyl chloride-based polymer.
[13]
means of solving the problem
[14]
The present invention includes the step of adding a vinyl chloride monomer and a monomer represented by the following formula (1) to a reactor and polymerization, and the amount of the monomer represented by the formula (1) is 1 to 4 parts by weight based on 100 parts by weight of the vinyl chloride monomer. It provides a method for producing a vinyl chloride-based polymer in which the monomer represented by Formula 1 is continuously added to the reactor:
[15]

[16]

[17]
In Formula 1,
[18]
R 1 and R 2 are each independently hydrogen or a C 1 to C 10 alkyl group.
[19]
Effects of the Invention
[20]
According to the method for producing a vinyl chloride-based polymer of the present invention, it is possible to prepare a vinyl chloride-based polymer with improved meltability while maintaining the thermal stability and polymerization time of the vinyl chloride-based polymer at the same level as that of a conventional vinyl chloride-based polymer. have.
[21]
Modes for carrying out the invention
[22]
Hereinafter, it will be described in more detail to help the understanding of the present invention.
[23]
[24]
The terms or words used in the present specification and claims are not to 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.
[25]
[26]
The term 'polymerization conversion rate' used in the present invention can be calculated by the following formula.
[27]
Polymerization conversion (%) = {(total weight of monomers added until polymerization is completed)-(total weight of unreacted monomers when polymerization conversion is measured)}/(total weight of monomers added until polymerization is complete) weight) × 100
[28]
[29]
Method for producing vinyl chloride-based polymer
[30]
The method for producing a vinyl chloride-based polymer according to an embodiment of the present invention includes adding a vinyl chloride monomer and a monomer represented by the following Chemical Formula 1 to a reactor and polymerization, and the amount of the monomer represented by Chemical Formula 1 is Based on 100 parts by weight of the vinyl chloride monomer, 1 to 4 parts by weight, the monomer represented by Formula 1 is continuously added to the reactor:
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[32]

[33]
In Formula 1,
[34]
R 1 and R 2 are each independently hydrogen or a C 1 to C 10 alkyl group.
[35]
[36]
The amount of the monomer represented by Formula 1 may be 1 to 4 parts by weight, preferably 2 to 3 parts by weight, based on 100 parts by weight of the vinyl chloride monomer. The monomer represented by Formula 1 may have lower reactivity compared to the vinyl chloride monomer, thereby lowering the polymerization rate and increasing the polymerization time. However, if it is added in the above-described content, a vinyl chloride-based polymer having improved meltability can be prepared while a polymerization rate decrease and an increase in polymerization time are minimized. However, if the monomer represented by Formula 1 is not added, or if it is added in less than the above-mentioned range, the meltability of the vinyl chloride-based polymer is not improved. In addition, if the monomer represented by Formula 1 is added in excess of the above-mentioned range, the polymerization rate is remarkably reduced and the polymerization time is significantly increased. In addition, the thermal stability of the prepared vinyl chloride-based polymer is significantly reduced.
[37]
[38]
In addition, when the monomer represented by Formula 1 is continuously added, the concentration of the monomer represented by Formula 1 is maintained low during polymerization in the polymerization reactor, so the polymerization rate decreases and polymerization time due to the monomer represented by Formula 1 increase can be minimized.
[39]
However, if the monomers represented by Chemical Formula 1 are batch-injected before polymerization starts, the polymerization rate is lowered and the polymerization time is significantly increased. In addition, the thermal stability of the prepared vinyl chloride-based polymer is reduced.
[40]
[41]
The starting time of continuous input of the monomer represented by Formula 1 may be a time when the polymerization conversion rate is 0.0% to 10.0%, preferably 0.0% to 5.0%. In addition, the time at which the continuous input of the monomer represented by Formula 1 ends may be a time when the polymerization conversion rate is 60.0% to 80.0%, preferably 65.0% to 75.0%. When the above-described conditions are satisfied, the monomer represented by Chemical Formula 1 is continuously added from the initial polymerization to the end of polymerization, so that the concentration of the monomer represented by Chemical Formula 1 in the polymerization solution may be kept low. Due to this, it is possible to minimize the decrease in polymerization rate, increase in polymerization time, and decrease in thermal stability caused by the monomer represented by Formula 1 above.
[42]
[43]
The monomer represented by Formula 1 is 1,1-dichloroethylene, 1,1-dichloro-1-propylene, 1,1-dichloro-1-butene, 1,1-dichloro-1-pentene, 1,1-dichloro It may be at least one selected from the group consisting of -1-hexene, 1,1-dichloro-1-heptene, 1,1-dichloro-1-octene and 1,1-dichloro-1-nonene, of which 1, 1-dichloroethylene is preferred.
[44]
[45]
The vinyl chloride monomer may be introduced into the reactor at once before polymerization starts for process convenience, or may be added separately before polymerization and during polymerization to improve productivity.
[46]
[47]
Meanwhile, the polymerization may be suspension polymerization.
[48]
The suspension polymerization may be carried out in the presence of an initiator, a dispersant and an aqueous solvent.
[49]
The initiator is dicumyl peroxide, dipentyl peroxide, di(3,5,5-trismethylhexanoyl)peroxide, dilauroyl peroxide, diisopropyl peroxidacarbonate, di-sec-butylperoxide Cydicarbonate, di (2-ethylhexyl) peroxy dicarbonate, t-butylperoxy neodecanoate, t-butylperoxy neoheptanoate, t-amyl peroxy neodecanoate, cumyl peroxyneode consisting of canoate, cumyl peroxyneoheptanoate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, azobis-2,4-dimethylvaleronitrile, potassium persulfate and ammonium persulfate It may be at least one selected from the group.
[50]
The dispersant 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.
[51]
The aqueous solvent may be at least one selected from the group consisting of distilled water and ion-exchanged water.
[52]
[53]
The polymerization may be terminated when the polymerization conversion is 85.0% to 95.0%, preferably 85.0% to 90.0%. When the above-described conditions are satisfied, the monomer represented by Chemical Formula 1, which is added in the latter half of the polymerization, may sufficiently participate in the polymerization.
[54]
When the polymerization is completed, the steps of stripping and dehydration to remove unreacted monomers may be further performed.
[55]
[56]
Hereinafter, preferred embodiments are presented to help the understanding of the present invention, but it is clear to those skilled in the art that various changes and modifications are possible within the scope of the present description and the scope of the technical spirit. It is natural that such variations and modifications fall within the scope of the appended claims.
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Example
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Examples 1 to 6 and Comparative Examples 1 to 7
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In a stainless polymerization reactor with an internal volume of 1 m equipped with a reflux condenser and stirrer, 130 parts by weight of ion-exchanged water, 0.05 parts by weight of polyvinyl alcohol having a degree of hydration of 88%, and 0.02 parts by weight of polyvinyl alcohol having a degree of hydration of 72% , 0.015 parts by weight of polyvinyl alcohol having a hydration degree of 55%, 0.0005 parts by weight of hydroxypropyl methylcellulose, and 0.088 parts by weight of t-butylperoxy neodecanoate were added. After that, while stirring the polymerization reactor, the inside was degassed with a vacuum pump. After that, 100 parts by weight of the vinyl chloride monomer is batch-injected into the polymerization reactor, and 1,1-dichloroethylene is introduced under the conditions shown in Tables 1 and 2 below while maintaining the internal temperature of the polymerization reactor at 57.2° C. or Polymerization was carried out while not added. Polymerization was stopped when the pressure of the polymerization reactor in which the polymerization was performed differed from the pressure of the polymerization reactor in the initial stage of polymerization by 1.0 kg/cm 2 . After adding 0.05 parts by weight of triethylene glycol bis(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate to the polymerization reactor, unreacted monomer and polymer slurry were respectively recovered in the polymerization reactor. . Then, the polymerization slurry was stripped and dehydrated to recover unreacted monomers and moisture, and dried with hot air in a fluidized bed dryer to obtain a vinyl chloride-based polymer.
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[63]
Experimental Example 1
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Polymerization conversion rates of the vinyl chloride-based polymers of Examples and Comparative Examples were calculated by the following method. And the results are shown in Tables 1 and 2 below.
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[66]
Polymerization conversion rate (%) = Polymerization conversion rate (%) = {(Total weight of vinyl chloride monomer and 1,1-dichloroethylene monomer added until polymerization is completed)-(Unreacted vinyl chloride at the time of measurement of polymerization conversion rate Total weight of monomer and 1,1-dichloroethylene monomer)}/(total weight of vinyl chloride monomer and 1,1-dichloroethylene monomer added until polymerization is complete) × 100
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Experimental Example 2
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100 parts by weight of the vinyl chloride-based copolymer of Examples and Comparative Examples, 5 parts by weight of a Ca-Zn-based stabilizer (NH390P manufactured by Danseok Industrial Co., Ltd.), 7 parts by weight of CPE7000 (Manufacturer: WEIPREN® from SUNDOW), and 12 parts by weight of CaCO 3 in a blender (HMF-3100S manufactured by Hanil Electric) and mixed for 6 minutes to prepare a thermoplastic resin composition. The physical properties of the thermoplastic resin composition were measured by the method described below, and the results are shown in Tables 1 and 2 below.
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[71]
Melting time (Fusion Time, seconds): The thermoplastic resin composition was put into a Brabender Plastograph Mixer, and the melting time was measured for 6 minutes at 165° C. and 45 rpm.
[72]
[73]
Experimental Example 3
[74]
The thermoplastic resin composition prepared in Experimental Example 2 was extruded by a twin-screw extruder (manufacturer: Brabender), and the extruded product was prepared as a specimen using a specimen cutter. The physical properties of the specimen were measured by the method described below, and the results are shown in Tables 1 and 2 below.
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[76]
Tensile yield strength (MPa): The specimen was measured with a tensile strength meter (Zwick-ZO10 manufactured by Zwick/Roell) according to ASTM D638.
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[78]
Experimental Example 4
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100 parts by weight of the vinyl chloride copolymer of Examples and Comparative Examples, 0.7 parts by weight of a tin-based stabilizer (MT800 of Songwon Industrial Co., Ltd.), 1.8 parts by weight of TiO 2 , and 1 part by weight of a processing aid (PA910 of LG Chem) are mixed for 1 minute One mixture was roll milled at 185° C. for 5 minutes to prepare a sheet. The physical properties of the sheet were measured by the method described below, and the results are shown in Tables 1 and 2 below.
[80]
[81]
Whiteness: It was measured with a spectrophotometer (KONICA MINOLTA CM-700d) based on the CIE 1976 (L*, a*, b*) colorimeter. It shows that it is excellent in thermal stability, so that the whiteness value is high.
[82]
[Table 1]
division Example 1 Example 2 Example 3 Example 4 Example 5 Example 6
1,1-dichloroethylene Input amount
(parts by weight) 1.0 2.0 3.0 4.0 4.0 4.0
dosing method continuity continuity continuity continuity continuity continuity
Input start time
(Polymerization conversion rate, %) 0.0 0.0 0.0 0.0 0.0 11.0
End of input
(polymerization conversion rate, %) 70.0 70.0 70.0 70.0 81.0 70.0
Total polymerization time (min) 172 176 181 187 171 198
Final polymerization conversion (%) 85.6 85.5 85.2 85.7 85.8 86.0
Thermoplastic resin composition melting time 158 145 128 112 142 118
Psalter tensile yield strength 38.9 39.4 39.8 40.3 40.1 39.9
Sheet whiteness 72.8 72.9 73.1 72.5 72.6 71.0
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[84]
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[Table 2]
division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7

1,1 -dichloroethylene Input amount
(parts by weight) 0.0 1.0 4.0 7.0 0.5 4.5 7.0
dosing method - batch batch batch continuity continuity continuity
Input start time (polymerization conversion rate, %) - - - - 0.0 0.0 0.0
End of input (polymerization conversion rate, %) - - - - 70.0 70.0 70.0
Total polymerization time (min) 170 217 283 524 172 204 277
Final polymerization conversion 85.2 85.3 85.9 85.4 85.5 86.0 85.4
Thermoplastic resin composition melting time 176 160 119 90 174 116 88
Psalter tensile yield strength 37.2 37.9 39.7 38.1 37.3 40.0 37.9
Sheet whiteness 73.0 71.1 69.2 ND 72.8 69.7 69.4
[90]
Referring to Tables 1 and 2, in Examples 1 to 6 in which 1,1-dichloroethylene was continuously added in 1 to 4 parts by weight, compared to Comparative Example 1 in which 1,1-dichloroethylene was not added, total polymerization The final polymerization conversion rate was high without excessive increase in time. In addition, Examples 1 to 6 had a shorter melting time than Comparative Example 1, and improved tensile yield strength. On the other hand, comparing Examples 4 to 6, Example 4 prepared while continuously adding 1,1-dichloroethylene from a polymerization conversion of 0.0% to a polymerization conversion of 70.0%, 1,1-dichloroethylene The melting time was shorter than in Example 5, which was prepared while continuously inputting from the time point when the polymerization conversion rate was 0.0% to the time point when the polymerization conversion rate was 81.0%. In addition, the tensile yield strength and whiteness of Example 4 were excellent compared to Example 6, which was prepared by continuously adding 1,1-dichloroethylene from the point in time when the polymerization conversion rate was 11.0% to the point in time when the polymerization conversion rate was 70.0%. Comparing 1 and Comparative Example 2, Example 1 prepared by continuously adding 1 part by weight of 1,1-dichloroethylene to Comparative Example 2 prepared by batching 1 part by weight of 1,1-dichloroethylene The total polymerization time was remarkable it was very short Example 1 had a shorter melting time than Comparative Example 2, and excellent tensile yield strength and whiteness.
[91]
Comparing Example 4 and Comparative Example 3, Example 4 prepared by continuously adding 4 parts by weight of 1,1-dichloroethylene compared to Comparative Example 3 prepared by batching 4 parts by weight of 1,1-dichloroethylene This was remarkably short. Example 4 had a shorter melting time than Comparative Example 3, and had excellent tensile yield strength and whiteness.
[92]
Comparing Comparative Example 4 and Comparative Example 7, Comparative Example 7, which was prepared by continuously adding 7 parts by weight of 1,1-dichloroethylene, compared to Comparative Example 4, which was prepared by batching in 7 parts by weight of 1,1-dichloroethylene, the total polymerization time This was remarkably short. In addition, in Comparative Example 4, the thermal stability was not good enough to measure the whiteness.
[93]
Comparative Example 5, prepared by continuously adding 0.5 parts by weight of 1,1-dichloroethylene, had a significantly longer melting time compared to Examples 1 to 6, and the tensile yield strength was not improved.
[94]
Comparative Example 6, prepared by continuously adding 4.5 parts by weight of 1,1-dichloroethylene, had a significantly longer total polymerization time compared to Examples 1 to 6, and the whiteness was lowered.
Claims
[Claim 1]
It comprises the step of adding a vinyl chloride monomer and a monomer represented by the following formula (1) to the reactor and polymerizing, wherein the amount of the monomer represented by the formula (1) is 1 to 4 parts by weight based on 100 parts by weight of the vinyl chloride monomer, Method for producing a vinyl chloride-based polymer in which the monomer represented by Formula 1 is continuously added to the reactor: In Formula 1, R 1 and R 2 are each independently hydrogen or a C 1 to C 10 alkyl group. .
[Claim 2]
The method according to claim 1, wherein the amount of the monomer represented by Formula 1 is 2 to 3 parts by weight based on 100 parts by weight of the vinyl chloride monomer.
[Claim 3]
The method for producing a vinyl chloride-based polymer according to claim 1, wherein the starting point of continuous input of the monomer represented by Formula 1 is a polymerization conversion rate of 0.0% to 10.0%.
[Claim 4]
The method for producing a vinyl chloride-based polymer according to claim 1, wherein the starting point of continuous input of the monomer represented by Formula 1 is a point in time when the polymerization conversion rate is 0.0% to 5.0%.
[Claim 5]
The method for producing a vinyl chloride-based polymer according to claim 1, wherein the time at which the continuous input of the monomer represented by Formula 1 is terminated is a time when the polymerization conversion rate is 60.0% to 80.0%.
[Claim 6]
The method for producing a vinyl chloride-based polymer according to claim 1, wherein the time at which the continuous input of the monomer represented by Formula 1 is terminated is a time when the polymerization conversion rate is 65.0% to 75.0%.
[Claim 7]
The method according to claim 1, wherein the monomer represented by Formula 1 is 1,1-dichloroethylene, 1,1-dichloro-1-propylene, 1,1-dichloro-1-butene, 1,1-dichloro-1-pentene, 1,1-dichloro-1-hexene, 1,1-dichloro-1-heptene, 1,1-dichloro-1-octene and 1,1-dichloro-1-nonene at least one selected from the group consisting of A method for producing a vinyl chloride-based polymer.
[Claim 8]
The method for producing a vinyl chloride-based polymer according to claim 1, wherein the polymerization is suspension polymerization.
[Claim 9]
The method for producing a vinyl chloride-based polymer according to claim 1, wherein the polymerization is terminated at a polymerization conversion of 85.0% to 95.0%.