Method for preparing vinyl chloride-based polymer

Abstract

The present invention relates to a method for preparing a vinyl chloride-based polymer by using suspension polymerization, in which a vinyl chloride-based polymer having a low gel content and a high degree of polymerization can be prepared by using a dispersant composition comprising a lipophilic additive together with a chain extender.

Description

Method for producing vinyl chloride polymer

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0098674, filed July 28, 2023, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a method for producing a novel high-polymerization vinyl chloride polymer, which has a high degree of polymerization and can minimize the content of gel that may be generated by a chain extender added during the manufacturing process for the purpose of increasing the degree of polymerization.

[0005] Due to the recent rapid proliferation of electric vehicles, the market for charging cables for electric vehicles is also rapidly expanding. Materials being considered for these cables include flame-retardant polyethylene (PE), thermoplastic polyurethane (TPU), and polyvinyl chloride (PVC).

[0006] However, polyethylene resins inherently have inherent flame retardancy limitations. To improve their flame retardancy, large amounts of flame retardants must be added. However, this excessive addition of flame retardants actually degrades the mechanical properties of the resin. Furthermore, while thermoplastic polyurethane resins exhibit satisfactory flame retardancy, they exhibit poor heat resistance.

[0007] Meanwhile, polyvinyl chloride resin (PVLC) is relatively inexpensive and offers excellent mechanical strength, weather resistance, insulation, and oil resistance, as well as a certain level of flame retardancy. However, its heat resistance is inadequate, and the heat generated during rapid charging can damage the PVLC coating. Therefore, for PVLC to be applied to charging cables, its flame retardancy and heat resistance must be further improved.

[0008] Chlorinated polyvinyl chloride (C-PVC), which is additionally chlorinated polyvinyl chloride resin, has been proposed as a method to improve the flame retardancy and heat resistance of polyvinyl chloride resin. However, chlorinated polyvinyl chloride is difficult to manufacture, and the manufacturing process is expensive, so it cannot take advantage of the relatively low price of existing polyvinyl chloride. In addition, because there are many partially highly chlorinated chains, these chains thermally decompose during the molding process, causing the problem of hydrogen chloride gas contaminating the mold surface. Furthermore, such contamination of the mold surface causes carbon marks to appear on the surface of the final molded product, which also reduces continuous productivity during molding.

[0009] As an alternative, one could consider increasing the polymerization degree of the polyvinyl chloride resin itself to improve heat resistance. The polymerization degree of general polyvinyl chloride resin is around 1,000, and even for polyvinyl chloride resins used for special purposes, the polymerization degree is only around 1,500. To increase the polymerization degree, the polymerization temperature must be significantly lowered during the manufacturing process of polyvinyl chloride resin. However, lowering the polymerization temperature reduces reactivity and lowers productivity, limiting the production of high-polymerization-degree polyvinyl chloride resin. Furthermore, adding large amounts of cross-linking agents or chain extenders to increase the polymerization degree could be considered, but this has the fatal drawback of causing fish-eye because the large amount of cross-linking agent formed by the large amount of cross-linking agent forms a large amount of gel.

[0010] Therefore, research is needed on a novel method for producing a vinyl chloride polymer that can further increase the degree of polymerization of the vinyl chloride polymer ultimately obtained while minimizing the gel content within the vinyl chloride polymer.

[0011] The present invention provides a novel method for producing a vinyl chloride polymer capable of producing a vinyl chloride polymer having a low gel content and a high degree of polymerization.

[0012] In order to solve the above-mentioned problem, the present invention provides a method for producing a novel vinyl chloride polymer.

[0013] Specifically, (1) the present invention provides a method for producing a vinyl chloride polymer, including a step (S1) of introducing polymerization water, an initiator, a dispersant composition, a chain extender, and a vinyl chloride monomer into a polymerization reactor and initiating a polymerization reaction, and a step (S2) of performing a polymerization reaction to produce a vinyl chloride polymer, wherein the dispersant composition includes a lipophilic additive, and the sum HLB value of the dispersant composition is 8 to 11.5.

[0014] (2) The present invention provides a method for producing a vinyl chloride polymer, wherein the polymerization reaction in (1) above is suspension polymerization.

[0015] (3) The present invention provides a method for producing a vinyl chloride polymer, wherein the dispersant composition comprises a hydrophilic dispersant and a lipophilic additive in the above (1) or (2), and the total HLB value of the dispersant composition is 9 to 11.5.

[0016] (4) The present invention provides a method for producing a vinyl chloride polymer, wherein the hydrophilic dispersant is a polyvinyl alcohol, a methyl cellulose-based dispersant, or a mixture thereof, in any one of the above (1) to (3).

[0017] (5) The present invention provides a method for producing a vinyl chloride polymer, wherein in any one of the above (1) to (4), the lipophilic additive is at least one selected from the group consisting of sorbitan monolaurate, sorbitan monostearate, sorbitan monopalmitate, sorbitan monooleate, sorbitan sesquioleate, sorbitan trioleate, sorbitan isostearate, and polyoxyethylene sorbitan monostearate.

[0018] (6) The present invention provides a method for producing a vinyl chloride polymer, wherein the dispersant composition and the chain extender are mixed in advance and then introduced into a polymerization reactor in any one of the above (1) to (5).

[0019] (7) The present invention provides a method for producing a vinyl chloride polymer, wherein the chain extender is diallyl isophthalate in any one of the above (1) to (6).

[0020] (8) The present invention provides a method for producing a vinyl chloride polymer, wherein the chain extender is added in an amount of 0.01 to 0.5 parts by weight relative to 100 parts by weight of a vinyl chloride monomer in any one of the above (1) to (7).

[0021] (9) The present invention provides a method for producing a vinyl chloride polymer, wherein the polymerization reaction is performed at a temperature of 50°C or lower in any one of the above (1) to (8).

[0022] (10) The present invention provides a method for producing a vinyl chloride polymer, wherein in any one of the above (1) to (9), the initiator is at least one selected from the group consisting of a polyacyl peroxide initiator, a peroxydicarbonate initiator, a peroxyester initiator, a sulfate initiator, and an azo initiator.

[0023] (11) The present invention provides a method for producing a vinyl chloride polymer, wherein the initiator is added in an amount of 0.02 to 0.2 parts by weight relative to 100 parts by weight of a vinyl chloride monomer in any one of the above (1) to (10).

[0024] (12) The present invention provides a method for producing a vinyl chloride polymer, wherein the polymerization reaction is performed in the presence of a protective colloid in any one of the above (1) to (11).

[0025] (13) The present invention provides a method for producing a vinyl chloride polymer, wherein the protective colloid is at least one selected from the group consisting of vinyl alcohol resin, cellulose, and unsaturated organic acid polymers, in any one of the above (1) to (12).

[0026] (14) The present invention provides a method for producing a vinyl chloride polymer, wherein the protective colloid is added in an amount of 0.03 to 3.0 parts by weight relative to 100 parts by weight of a vinyl chloride monomer in any one of the above (1) to (13).

[0027] (15) The present invention provides a method for producing a vinyl chloride polymer, wherein the gel content of the vinyl chloride polymer is 5 wt% or less in any one of the above (1) to (14).

[0028] In the manufacturing method of the present invention, by using a dispersant composition including a lipophilic additive together with a chain extender, it is possible to manufacture a vinyl chloride polymer having a high degree of polymerization while minimizing the gel content that may occur due to the addition of a chain extender, and the vinyl chloride polymer manufactured in the present invention can be used in various fields requiring high strength, wear resistance, and long-term heat resistance.

[0029] Hereinafter, the present invention will be described in more detail.

[0030] Terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0031] Meanwhile, the term "vinyl chloride polymer" used in this specification encompasses a compound produced by polymerizing a vinyl chloride monomer, i.e., a vinyl chloride monomer alone or a mixture of a vinyl chloride monomer and a vinyl monomer copolymerizable with the vinyl chloride monomer, and may mean a polymer chain derived from a vinyl chloride monomer.

[0032]

[0033] Method for producing vinyl chloride polymer

[0034] The present invention provides a method for producing a vinyl chloride polymer, comprising the steps of (S1) introducing polymerization water, an initiator, a dispersant composition, a chain extender, and a vinyl chloride monomer into a polymerization reactor and initiating a polymerization reaction, and (S2) performing the polymerization reaction to produce a vinyl chloride polymer, wherein the dispersant composition includes a lipophilic additive, and the sum HLB value of the dispersant composition is 8 to 11.5.

[0035] According to the method for producing a vinyl chloride polymer of the present invention, when a dispersant composition including a lipophilic additive is applied while controlling the total HLB within an appropriate range together with a chain extender, the degree of polymerization can be increased by the chain extender while minimizing gel formation, which is a side effect of the chain extender.

[0036]

[0037] Hereinafter, the method for producing a vinyl chloride polymer of the present invention is explained step by step.

[0038]

[0039] Polymerization reaction initiation step (S1)

[0040] The method for producing a vinyl chloride polymer of the present invention includes a step (S1) of introducing polymerization water, an initiator, a dispersant composition, a chain extender, and a vinyl chloride monomer into a polymerization reactor and initiating a polymerization reaction.

[0041] The above step S1 is a step for initiating a polymerization reaction according to a general method for producing a vinyl chloride polymer. In particular, the polymerization method in the method for producing a vinyl chloride polymer of the present invention is suspension polymerization, and the suspension polymerization may be performed in the presence of polymerization water. The polymerization water is a polymerization solvent, and various types of polymerization water such as distilled water or deionized water may be used, and deionized water is preferably used. The temperature of the polymerization water may be appropriately selected in consideration of the temperature at which suspension polymerization takes place, and the amount of the polymerization water may also be appropriately used depending on the polymerization conditions. For example, it may be used in an amount of 70 parts by weight or more, specifically 70 to 300 parts by weight, based on 100 parts by weight of the vinyl chloride monomer.

[0042]

[0043] The above initiator is not particularly limited as long as it is applicable to suspension polymerization of a vinyl chloride monomer, and specifically, the initiator may be at least one selected from the group consisting of a polyacyl peroxide initiator, a peroxydicarbonate initiator, a peroxyester initiator, a sulfate initiator, and an azo initiator.

[0044] More specifically, the diacyl peroxide initiator may be at least one selected from the group consisting of dicumyl peroxide, dipentyl peroxide, 3,3,5-trimethyl hexanoyl peroxide, and dilauryl peroxide. The peroxydicarbonate initiator may be at least one selected from the group consisting of diisopropyl peroxydicarbonate, di-sec-butylperoxydicarbonate, and di-2-ethylhexyl peroxide. The peroxyester initiator may be t-butylperoxypivalate, cumylperoxydecanoate, or t-butylperoxy neodecanoate, or a mixture thereof. The sulfate initiator may be potassium persulfate, ammonium persulfate, or a mixture thereof. The azo initiator may be azobis-2,4-dimethylvaleronitrile.

[0045] The above initiator may be added in an amount of 0.02 to 0.2 parts by weight relative to 100 parts by weight of the vinyl chloride monomer, and preferably 0.04 to 0.12 parts by weight. If the amount of initiator added is too small, the reaction time is delayed, resulting in a decrease in productivity. If the amount of initiator added is too large, the initiator may not be completely consumed during the polymerization process and may remain in the vinyl chloride polymer ultimately produced, which may lower the thermal stability of the resin.

[0046]

[0047] The above dispersant composition comprises a lipophilic additive capable of inhibiting gel formation by a chain extender. More specifically, the dispersant composition may comprise a hydrophilic dispersant that serves to disperse a vinyl chloride monomer in a polymerization solution, and the lipophilic additive.

[0048] In the present invention, by appropriately controlling the HLB values ​​of the two components included in the dispersant composition and the ratio therebetween, both the dispersing effect and the gel formation inhibition effect can be maximized. More specifically, the combined HLB value of the dispersant composition can be 8 to 11.5, more preferably 8 or more, 8.3 or more, 8.6 or more, 8.8 or more, or 9 or more, and at the same time 11.5 or less, 11.4 or less, or 11.3 or less.

[0049] The above HLB value represents the hydrophilic-lipophilic balance, and a higher HLB value means a higher hydrophilicity. The above combined HLB value means an average value based on the weight of the HLB value of each component. For example, the combined HLB value of 60 wt% of component A with an HLB of 10 and 40 wt% of component B with an HLB of 5 is 10*0.6+5*0.4=8.

[0050] The hydrophilic dispersant included in the above dispersant composition is a component having a higher HLB, and its specific HLB value may be 12 or more, 14 or more, or 16 or more, and 20 or less, or 19 or less. The lipophilic additive is a component having a lower HLB, and may be 12 or less, 10 or less, or 9 or less, and 2 or more, 3 or more, or 4 or more.

[0051] More specifically, the hydrophilic dispersant may be polyvinyl alcohol, a methyl cellulose-based dispersant, or a mixture thereof, and the lipophilic additive may be at least one selected from the group consisting of sorbitan monolaurate, sorbitan monostearate, sorbitan monopalmitate, sorbitan monooleate, sorbitan sesquioleate, sorbitan trioleate, sorbitan isostearate, and polyoxyethylene sorbitan monostearate. The hydrophilic dispersant and lipophilic additive listed above are components having appropriate hydrophilicity and lipophilicity, and if the components are combined in an appropriate weight ratio and used after adjusting the combined HLB to be within the range described above, the degree of polymerization of the vinyl chloride-based polymer can be further increased while minimizing gel formation.

[0052] The above dispersant composition may be added in an amount of 0.01 to 0.5 parts by weight relative to 100 parts by weight of the vinyl chloride monomer, and preferably 0.01 parts by weight or more, 0.02 parts by weight or more, 0.03 parts by weight or more, 0.04 parts by weight or more, or 0.05 parts by weight or more, and 0.5 parts by weight or less, 0.45 parts by weight or less, 0.4 parts by weight or less, 0.35 parts by weight or less, or 0.3 parts by weight or less. If the amount of the above dispersant composition added is too little, dispersion of the vinyl chloride monomer and the chain extender itself may be difficult, and if too much, the physical properties of the vinyl chloride polymer produced may be undesirable.

[0053] Meanwhile, it may be preferable to pre-mix the dispersant composition and chain extender before introducing them into the polymerization reactor. When the dispersant composition and chain extender are not directly introduced into the polymerization reactor individually, but rather are pre-mixed and then introduced together, gel formation can be further suppressed by appropriate mixing of the chain extender and the lipophilic additive.

[0054]

[0055] The above chain extender functions to increase the degree of polymerization by extending the formed vinyl chloride polymer chain. Conventionally, phthalate-based components are known to be commonly used as chain extenders. However, when phthalates are used, the chain extension efficiency is low, so a large amount must be added to produce a polymer with a high degree of polymerization, which is not economical. In addition, phthalates themselves are designated as toxic substances due to their high acute toxicity levels, and there is a problem that toxicity may remain in the vinyl chloride polymer that is ultimately produced. Therefore, the chain extender used in the present invention may be preferably an isophthalate-based chain extender. In the case of isophthalate-based chain extenders, they have the technical advantage of having excellent chain extension efficiency, so that sufficient chain extension efficiency can be exhibited even with a relatively small amount, while being non-toxic, so that the toxicity of the vinyl chloride polymer that is ultimately produced is also low.

[0056] The chain extender used in the present invention may preferably have excellent compatibility with a vinyl chloride monomer, and may particularly be diallyl isophthalate.

[0057] The chain extender may be added in an amount of 0.01 to 0.5 parts by weight, and preferably 0.05 to 0.3 parts by weight, based on 100 parts by weight of the vinyl chloride monomer. If the amount of the chain extender added is too small, the degree of polymerization of the vinyl chloride polymer produced cannot be sufficiently increased, and thus the purpose of the present invention to produce a vinyl chloride polymer with a high degree of polymerization cannot be achieved. If the amount of the chain extender added is too large, the gel content may rapidly increase due to the excessively added chain extender.

[0058]

[0059] Meanwhile, the polymerization reaction initiated in the above step S1 may be performed in the presence of a protective colloid. The protective colloid may be at least one selected from the group consisting of vinyl alcohol resin, cellulose, and unsaturated organic acid polymers.

[0060] The vinyl alcohol resin used as the protective colloid may preferably have a hydration degree of 30 to 90 wt% and a viscosity of 10 to 60 cps as a 4% aqueous solution at 15 to 25°C. In addition, the cellulose used as the protective colloid may preferably have a content of hydroxypropyl groups of 3 to 20 wt% and a viscosity of 10 to 20,000 cps as a 2% aqueous solution at 15 to 25°C. In addition, the unsaturated organic acid polymer used as the protective colloid may be at least one selected from the group consisting of acrylic acid polymers, methacrylic acid polymers, itaconic acid polymers, fumaric acid polymers, maleic acid polymers, succinic acid polymers, and gelatin. When a protective colloid satisfying the above-described conditions is used, the stability of the vinyl chloride monomer during the manufacturing process can be further improved.

[0061] The above protective colloid may be added in an amount of 0.03 to 3.0 parts by weight relative to 100 parts by weight of the vinyl chloride monomer, and particularly preferably, 0.05 to 2.0 parts by weight. When the amount of the protective colloid added is within the above-described preferred range, droplet stability increases, so that the breakage and agglomeration of particles are appropriately controlled during the production of the vinyl chloride polymer, and thus, a vinyl chloride polymer including desirable internal voids can be produced.

[0062] In this step, a hydrogen ion concentration regulator may be added to the polymerization reactor as needed. Examples of hydrogen ion concentration regulators that can be used in the present invention include sodium bicarbonate (NaHCO3), sodium borate (Na2B4O7), sodium phosphate dibasic (Na2HPO4), sodium carbonate (Na2CO3), potassium dihydrogen phosphate (KH2PO4), ammonium hydroxide (NH4OH), potassium tartrate (KHC4H4O6), potassium hydrogen phthalate (KHC8H4O4), or calcium hydroxide (Ca(OH)2). These may be used alone or in combination of two or more thereof.

[0063]

[0064] Polymerization reaction progress stage (S2)

[0065] After initiating the polymerization reaction as described above, the polymerization reaction can be continued for a certain period of time under certain temperature conditions to ultimately produce a vinyl chloride polymer, and accordingly, a step (S2) for performing the polymerization reaction can be performed.

[0066]

[0067] The temperature conditions at which the polymerization reaction is carried out in this step may be 50°C or lower, preferably 30 to 50°C, and particularly preferably 40 to 50°C. As the temperature at which the polymerization reaction is carried out decreases, the degree of polymerization of the obtained vinyl chloride polymer increases. However, if the reaction temperature is excessively low, the reaction rate decreases significantly, and the productivity of the vinyl chloride polymer manufacturing process decreases significantly. Therefore, within the above temperature condition range, a high-polymerization degree vinyl chloride polymer of excellent quality can be efficiently manufactured while minimizing the decrease in productivity.

[0068] In this step, the reaction can be terminated by introducing a reaction terminator. The reaction terminator can terminate the polymerization reaction by reacting with the remaining unreacted initiator, thereby causing the initiator to lose its function, and may be at least one selected from the group consisting of phenol compounds, amine compounds, nitrile compounds, and sulfur compounds. The above phenol compounds are triethylene glycol-bis-3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate, hydroquinone, p-methoxy phenol, t-butyl-4-hydroxyanisole, n-octadecyl-3-(4-hydroxy-3,5-di-t-butylphenyl)propionate, 2,5-di-t-butyl hydroquinone, 4,4'-butylidene bis(3-methyl-6-t-butyl The amine compound may be at least one selected from the group consisting of N,N-diphenyl-p-phenylenediamine and 4,4-bis(dimethylbenzyl)diphenyl.The nitrile compound may be at least one selected from the group consisting of 2-phenyl nitronyl nitroxide, 3-imidazoline nitroxide, and 4-hydroxy-2,2,6,6-tetramethyl piperidine 1-oxyl. The sulfur compound may be at least one selected from the group consisting of dodecyl mercaptan and 1,2-biphenyl-2-thiol.

[0069]

[0070] In the method for producing a vinyl chloride polymer of the present invention, additives such as antioxidants, bases, crosslinking agents, polymerization regulators, chain transfer agents, antistatic agents, scale inhibitors, and surfactants may be additionally added. The types and contents of the additives are not particularly limited, and any conventional types and contents known in the art may be used. The additives may be added at any point during the polymerization process, and may be added all at once or continuously.

[0071]

[0072] Dehydration and drying stage (S3)

[0073] The method for producing a vinyl chloride polymer of the present invention may include a step (S3) of dehydrating and drying the polymerization reaction product obtained after the polymerization reaction is completed through the preceding step.

[0074] The dehydration and drying methods in this step are not particularly limited, and any known dehydration and drying method for the production of vinyl chloride polymers can be applied without particular limitation. For example, the final vinyl chloride polymer can be obtained by first dehydrating using equipment such as a centrifuge, and then secondarily drying using equipment such as a fluidized bed dryer. The vinyl chloride polymer obtained after the dehydration and drying steps may be in the form of beads.

[0075]

[0076] The gel content of the vinyl chloride polymer produced through the method for producing a vinyl chloride polymer of the present invention described above may be 5 wt% or less, preferably 4 wt% or less or 3.5 wt% or less. The vinyl chloride polymer produced through the method for producing a vinyl chloride polymer of the present invention is a high-polymerization vinyl chloride polymer with a low gel content, and thus may be particularly suitable for use as a material for various purposes requiring high strength, wear resistance, and long-term heat resistance.

[0077] In addition, the average particle size of the vinyl chloride polymer produced through the method for producing a vinyl chloride polymer of the present invention may be 100 µm or more and 200 µm or less, and preferably 100 µm or more, 105 µm or more, 110 µm or more, or 115 µm or more, and 200 µm or less, 195 µm or less, 190 µm or less, 185 µm or less, 180 µm or less, 175 µm or less, 170 µm or less, 165 µm or less, or 60 µm or less. When the average particle size of the vinyl chloride polymer is within the above-described range, handling may be particularly easy.

[0078]

[0079] Hereinafter, preferred examples are presented to aid understanding of the present invention. However, the following examples are intended only to illustrate the present invention and are not intended to limit its scope.

[0080]

[0081] ingredient

[0082] Polyvinyl alcohol with an HLB value of 18 was used as a hydrophilic dispersant, and sorbitan monolaurate (product name: SPAN20) with an HLB value of 8.6 or sorbitan monostearate (product name: SPAN60) with an HLB value of 4.7 was used as a lipophilic additive.

[0083]

[0084] Example 1

[0085] A mixture containing a dispersant composition and a chain extender was prepared by pre-mixing diallyl isophthalate and sorbitan monolaurate, a lipophilic additive, for 1 hour. The total HLB of the dispersant composition was set to 8.6. Afterwards, a 1 m internal volume reflux condenser and a stirrer were installed. 3 390 kg of deionized water was charged into a stainless steel polymerization reactor, and 150 g of polyvinyl alcohol having a hydration degree of 78.5 mol%, 100 g of polyvinyl alcohol having a hydration degree of 40.7 mol%, 30 g of hydroxypropyl methyl cellulose as a protective colloid, and the mixture prepared above were charged into the reactor all at once. At this time, the amount of sorbitan monolaurate in the dispersant composition was set to 0.1 part by weight based on 100 parts by weight of vinyl chloride monomer to be charged later, and the amount of diallyl isophthalate was set to 0.15 part by weight based on vinyl chloride monomer. Thereafter, 300 kg of vinyl chloride monomer was charged, and 240 g of a 75 wt% solution of t-butylperoxy neodecanoate as an organic peroxide initiator composition was charged, and then the temperature of the reactor was raised to 47°C to initiate a polymerization reaction.

[0086] Afterwards, the polymerization reaction was continued while maintaining the reaction temperature at 47℃, and the pressure of the polymerization reactor was 5.8kg / cm 2At the point where the reaction reached , 15 g of 4-hydroxy-2,2,6,6-tetramethyl-piperidine-1-oxyl and 60 g of triethylene glycol-bis-3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate were added as reaction terminators to terminate the reaction. Subsequently, unreacted monomer and polymer slurry were recovered from the reactor, and the polymer slurry was dehydrated and dried in a fluidized bed dryer to obtain a vinyl chloride polymer in the form of beads.

[0087]

[0088] Example 2

[0089] In the above Example 1, a dispersing composition further included polyvinyl alcohol, but the amount of polyvinyl alcohol added was 0.01 parts by weight based on 100 parts by weight of a vinyl chloride monomer, thereby using a dispersing composition having a total HLB of 9.5, and the same procedure was performed to obtain a vinyl chloride polymer.

[0090]

[0091] Example 3

[0092] In the above Example 1, a vinyl chloride polymer was obtained by performing the same procedure except that polyvinyl alcohol was further included as a dispersant composition, but the amount of polyvinyl alcohol added was 0.02 parts by weight based on 100 parts by weight of a vinyl chloride monomer, thereby using a composition having a total HLB of 10.2.

[0093]

[0094] Example 4

[0095] In the above Example 1, a vinyl chloride polymer was obtained by performing the same procedure except that polyvinyl alcohol was further included as a dispersant composition, but the amount of polyvinyl alcohol added was 0.03 parts by weight based on 100 parts by weight of vinyl chloride monomer, thereby using a composition having a total HLB of 10.8.

[0096]

[0097] Example 5

[0098] In the above Example 1, a vinyl chloride polymer was obtained by performing the same procedure except that a composition having a total HLB of 11.3 was used by further including polyvinyl alcohol as a dispersant composition, but the amount of polyvinyl alcohol added was 0.04 parts by weight based on 100 parts by weight of vinyl chloride monomer.

[0099]

[0100] Comparative Example 1

[0101] In the above Example 1, a vinyl chloride polymer was obtained by performing the same procedure except that the dispersant composition was not added.

[0102]

[0103] Comparative Example 2

[0104] In the above Example 1, a vinyl chloride polymer was obtained by performing the same procedure except that the dispersant composition did not include a lipophilic additive and only included 0.03 parts by weight of a hydrophilic dispersant relative to 100 parts by weight of a vinyl chloride monomer.

[0105]

[0106] Comparative Example 3

[0107] In the above Example 1, a vinyl chloride polymer was obtained by performing the same procedure except that the dispersant composition did not include a lipophilic additive and only included 0.1 part by weight of a hydrophilic dispersant relative to 100 parts by weight of a vinyl chloride monomer.

[0108]

[0109] Comparative Example 4

[0110] In the above Example 1, a vinyl chloride polymer was obtained by performing the same procedure except that polyvinyl alcohol was further included as a dispersant composition, but the amount of polyvinyl alcohol added was 0.05 parts by weight based on 100 parts by weight of vinyl chloride monomer, thereby using a composition having a total HLB of 11.7.

[0111]

[0112] Comparative Example 5

[0113] In the above Example 1, a vinyl chloride polymer was obtained by performing the same procedure except that polyvinyl alcohol was further included as a dispersant composition, but the amount of polyvinyl alcohol added was 0.06 parts by weight based on 100 parts by weight of vinyl chloride monomer, thereby using a composition having a total HLB of 12.1.

[0114]

[0115] The HLB values, dosages, and total HLB values ​​of the hydrophilic dispersants and lipophilic additives used in Examples 1 to 5 and Comparative Examples 1 to 5 are summarized in Table 1 below. Meanwhile, the dosage in Table 1 below refers to the weight part value added relative to 100 weight parts of vinyl chloride.

[0116] Hydrophilic dispersantLipophilic additiveTotal HLB valueHLB valueDosageHLB valueDosageComparative example 1-----Comparative example 2180.03--18Comparative example 3180.1--18Example 1--8.60.18.6Example 2180.018.60.19.5Example 3180.028.60.110.2Example 4180.038.60.110.8Example 5180.048.60.111.3Comparative example 4180.058.60.111.7Comparative example 5180.068.60.112.1

[0117] Examples 6 to 13 and Comparative Examples 6 to 8

[0118] In the manufacturing process of Examples 1 to 5 and Comparative Examples 1 to 5, a vinyl chloride polymer was manufactured in the same manner as in Examples 1 to 5, except that sorbitan monostearate having an HLB value of 4.7 was used instead of sorbitan monolaurate having an HLB value of 8.6 as a lipophilic additive, and the amounts of the hydrophilic dispersant and lipophilic additive were adjusted.

[0119] The HLB values, dosages, and total HLB values ​​of the hydrophilic dispersants and lipophilic additives used in Examples 6 to 13 and Comparative Examples 6 to 8 are summarized in Table 2 below. Meanwhile, the dosages in Table 2 below also refer to the weight parts added relative to 100 weight parts of vinyl chloride.

[0120] Hydrophilic dispersantLipophilic additiveTotal HLB valueHLB valueDosageHLB valueDosageComparative example 6180.014.70.15.9Comparative example 7180.024.70.16.9Comparative example 8180.034.70.17.8Example 6180.014.70.0111.4Example 7180.014.70.0258.5Example 8180.024.70.0211.4Example 9180.024.70.058.5Example 10180.034.70.0311.4Example 11180.034.70.0758.5Example 12180.044.70.0411.4 Example 13180.044.70.18.5

[0121] Experimental Example 1. Measurement of the degree of polymerization, gel content, and average particle size of the manufactured vinyl chloride polymer.

[0122] The degree of polymerization and gel content of the vinyl chloride polymers manufactured in the above examples and comparative examples were measured.

[0123] 1) Degree of polymerization: 0.2 g of vinyl chloride polymer obtained through drying after polymerization was dissolved in a cyclohexanone solvent, and then measured using an Ubbelohd viscometer using the specific viscosity method.

[0124] 2) Gel content: After weighing the cylindrical filter (Thimble filter), a vinyl chloride polymer was placed inside and inserted into a Soxhlet extractor. 500 ml of tetrahydrofuran was added to a 1 L flask, all the glassware was connected, and stirring, heating, and refluxing were started at 95℃, which is higher than the boiling point of tetrahydrofuran, while flowing water into the reflux condenser. After 48 hours of reflux, the cylindrical filter was taken out, dried in an oven, and then weighed. The gel content was measured as the difference in the weight of the filter (weight of the filter before reflux / weight of the filter after reflux * 100%).

[0125] 3) Average particle size: The average particle size was measured using a HELOS particle size analyzer according to ISO 13320.

[0126]

[0127] The measurement results are summarized in Tables 3 and 4 below.

[0128] Polymerization degree Gel content (wt%) Average particle size (㎛) Example 133 103.1150 Example 235 402.6141 Example 338 101.2129 Example 440 500 119 Example 539 700.5195 Comparative example 121 2012.3148 Comparative example 223 0010.6113 Comparative example 325 009.574 Comparative example 439 300.697 Comparative example 539 200.690

[0129] Polymerization degree Gel content (weight %) Comparative example 6238010.3 Comparative example 724509.8 Comparative example 825508.1 Example 639400.6 Example 734202.9 Example 839800.5 Example 935502.5 Example 1040000.4 Example 1136402.3 Example 1240100.4 Example 1337101.8

[0130] As can be seen from Tables 3 and 4 above, it was confirmed that the vinyl chloride polymers manufactured through the examples of the present invention exhibited low gel content and high polymerization degree. On the other hand, in the case of Comparative Examples 1 to 3 that did not use a lipophilic additive, vinyl chloride polymers with high gel content and low polymerization degree were manufactured, and through this, it can be confirmed that when a lipophilic additive is applied together with a hydrophilic dispersant as in the manufacturing method of the present invention, improved effects in terms of polymerization degree and gel content can be achieved.

[0131] Meanwhile, in Comparative Examples 4 and 5, which used the same lipophilic additive but had a total HLB value of more than 11.5 of the dispersant composition, the gel content and polymerization degree were similarly excellent to the examples, but it was confirmed that problems occurred in terms of the particle size, which is a basic property of the manufactured vinyl chloride polymer, such as the particle size being excessively small and the bulk density being excessively high. If the particle size of the vinyl chloride polymer is excessively small, a large amount of fine powder may be generated in the work environment, which may cause a problem of reduced workability. Through this, it was confirmed that it is difficult to satisfy the basic property range of the vinyl chloride polymer if the hydrophilic dispersant and the lipophilic additive are not used appropriately. On the other hand, in Comparative Examples 8 to 10, where the HLB value is less than 8, vinyl chloride polymers having a high gel content and a low polymerization degree were manufactured, similar to Comparative Examples 1 to 3, which did not use the lipophilic additive.

[0132] From this, it was confirmed that in order to manufacture a vinyl chloride polymer having a high degree of polymerization, a low gel content, and capable of satisfying the physical properties range of a basic vinyl chloride polymer, a dispersant composition including a lipophilic additive and having a total HLB value of 8 to 11.5 and a chain extender must be used together.

Claims

1. Step (S1) of introducing polymerization water, initiator, dispersant composition, chain extender and vinyl chloride monomer into a polymerization reactor and initiating a polymerization reaction; and It includes a step (S2) of producing a vinyl chloride polymer by performing a polymerization reaction; The above dispersant composition comprises a lipophilic additive, A method for producing a vinyl chloride polymer having a total HLB value of the above dispersant composition of 8 to 11.

5.

2. In paragraph 1, A method for producing a vinyl chloride polymer, wherein the above polymerization reaction is suspension polymerization.

3. In paragraph 1, The above dispersant composition comprises a hydrophilic dispersant and a lipophilic additive, A method for producing a vinyl chloride polymer, wherein the total HLB value of the above dispersant composition is 9 to 11.

5.

4. In paragraph 3, A method for producing a vinyl chloride polymer, wherein the hydrophilic dispersant is a polyvinyl alcohol, a methyl cellulose-based dispersant, or a mixture thereof.

5. In paragraph 1, A method for producing a vinyl chloride polymer, wherein the lipophilic additive is at least one selected from the group consisting of sorbitan monolaurate, sorbitan monostearate, sorbitan monopalmitate, sorbitan monooleate, sorbitan sesquioleate, sorbitan trioleate, sorbitan isostearate, and polyoxyethylene sorbitan monostearate.

6. In paragraph 1, A method for producing a vinyl chloride polymer, wherein the above dispersant composition and chain extender are mixed in advance and then introduced into a polymerization reactor.

7. In paragraph 1, A method for producing a vinyl chloride polymer, wherein the chain extender is diallyl isophthalate.

8. In paragraph 1, A method for producing a vinyl chloride polymer, wherein the chain extender is added in an amount of 0.01 to 0.5 parts by weight relative to 100 parts by weight of a vinyl chloride monomer.

9. In paragraph 1, A method for producing a vinyl chloride polymer, wherein the above polymerization reaction is performed at a temperature of 50°C or lower.

10. In paragraph 1, A method for producing a vinyl chloride polymer, wherein the above initiator is at least one selected from the group consisting of a polyacyl peroxide initiator, a peroxydicarbonate initiator, a peroxyester initiator, a sulfate initiator, and an azo initiator.

11. In paragraph 1, A method for producing a vinyl chloride polymer, wherein the above initiator is added in an amount of 0.02 to 0.2 parts by weight relative to 100 parts by weight of a vinyl chloride monomer.

12. In paragraph 1, A method for producing a vinyl chloride polymer, wherein the above polymerization reaction is performed in the presence of a protective colloid.

13. In paragraph 12, A method for producing a vinyl chloride polymer, wherein the above protective colloid is at least one selected from the group consisting of vinyl alcohol resin, cellulose, and unsaturated organic acid polymers.

14. In paragraph 12, A method for producing a vinyl chloride polymer, wherein the above protective colloid is added in an amount of 0.03 to 3.0 parts by weight relative to 100 parts by weight of a vinyl chloride monomer.

15. In paragraph 1, A method for producing a vinyl chloride polymer, wherein the gel content of the vinyl chloride polymer is 5 wt% or less.