KR102342102B1 - Vinyl chloride polymer, preparation method thereof and plastisol comprising the same - Google Patents

Abstract

The present invention relates to a vinyl chloride-based polymer, a method for preparing the same, and a plastisol containing the same. Accordingly, the vinyl chloride-based polymer has a particle size distribution characteristic in which particles having a relatively small particle size and particles having a relatively large particle size are distributed in a specific ratio, so that it can exhibit high viscosity characteristics in a low shear region, and as the shear rate increases, Viscosity and stress can exhibit lower flow characteristics, so it can be easily used in spray coating processes, etc., and exhibits excellent tensile strength and elongation to improve quality when processing into coating agents or various molded articles.
Therefore, the vinyl chloride-based polymer and the method for producing the same according to the present invention can be easily applied to an industry requiring the same, for example, a vinyl chloride-based resin industry for paste processing.

Description

Vinyl chloride-based polymer, manufacturing method thereof, and plastisol comprising the same

The present invention relates to a vinyl chloride-based polymer, a method for preparing the same, and a plastisol containing the same.

A vinyl chloride-based polymer is a resin containing 50% or more of vinyl chloride, and has a wide range of applications because it is inexpensive, can easily control hardness, and can be applied to most processing equipment. In addition, it can provide a molded article having excellent physical and chemical properties, such as mechanical strength, weather resistance, chemical resistance, and the like, and thus is widely used in various fields.

These vinyl chloride-based polymers are prepared in different forms depending on the use. For example, vinyl chloride-based polymers for straight processing such as extrusion, calendar, and injection processes are generally prepared by suspension polymerization, and vinyl chloride-based polymers for paste processing such as dipping, spraying, and coating are manufactured by emulsion polymerization.

The paste processing generally forms final resin particles by drying the vinyl chloride-based polymer latex obtained by emulsion polymerization by spray drying, and the particles are dispersed in a solvent or plasticizer to coat (reverse roll-coating, knife coating, screen coating, spray coating), gravure and screen printing, rotation casting, shell casting and dipping, flooring, wallpaper, tarpaulin, raincoat, It is applied to products such as gloves, automotive underbody coatings, sealants, and carpet tiles.

Such a vinyl chloride-based polymer for paste processing alone is difficult to apply due to its low processability, and is usually processed and used in the form of a plastisol composed of various additives such as a heat stabilizer together with a plasticizer. It is important to lower the viscosity of the stisol to maintain good flowability.

In particular, in the case of a vinyl chloride polymer used for sealant or automobile underbody coating, it is applied to an adherend using a robot spray gun or a squeezing bottle, etc., and then is coated through a drying process. This creates an environment with a high shear rate, and when the viscosity of the vinyl chloride-based polymer is too high at a high shear rate, the flowability is not good, so the spraying force is low, and there is a problem in that it is not uniformly applied to the adherend.

In addition, when the viscosity of the vinyl chloride-based polymer is low, the vinyl chloride-based polymer is agglomerated into droplets or separated from the adherend while having fluidity due to gravity before drying after being applied to the adherend. As a result, there is a problem in that the coating thickness becomes non-uniform and the vinyl chloride-based polymer is formed shallowly in a specific area, resulting in defects.

Therefore, in order to use the vinyl chloride-based polymer in the application process using spray coating, it is necessary to realize the flow characteristics of a pseudoplastic fluid in which the viscosity decreases as the shear rate increases.

That is, in order to use the vinyl chloride-based polymer for a sealant or automobile underbody coating through a paste processing, for example, an application process using spray coating, it exhibits high viscosity characteristics in a region where the shear rate is zero or a low shear rate, and as the shear rate increases, There is a need to develop a vinyl chloride-based polymer capable of exhibiting a characteristic of decreasing viscosity.

JP 2970659 B2 (199.08.27)

The present invention has been devised to solve the problems of the prior art, and it is an object of the present invention to provide a vinyl chloride-based polymer that exhibits a high viscosity characteristic in a low shear region and a low viscosity characteristic by decreasing viscosity and stress as the shear rate increases. do it with

Another object of the present invention is to provide a method for producing the vinyl chloride-based polymer.

Another object of the present invention is to provide a plastisol comprising the vinyl chloride-based polymer.

In order to solve the above problems, the vinyl chloride-based polymer according to an embodiment of the present invention is a vinyl chloride-based polymer having a bimodal particle size distribution, and 40 to 65 wt% of small-diameter particles having a particle diameter of 0.1 μm to 0.39 μm. and 35 to 60% by weight of large-diameter particles having a particle diameter of 0.4 μm to 3.0 μm.

In addition, there is provided a method for producing the vinyl chloride-based polymer comprising the step of emulsion polymerization of a vinyl chloride-based monomer in the presence of seed particles.

In addition, there is provided a plastisol comprising the vinyl chloride-based polymer.

The vinyl chloride-based polymer according to the present invention has a particle size distribution characteristic in which particles having a relatively small particle diameter and particles having a relatively large particle diameter are distributed in a specific ratio, so that it can exhibit high viscosity characteristics in a low shear region, so that it can be applied to an adherend The flow-down phenomenon is prevented, so the occurrence rate of defects such as separation from the adherend and non-uniform coating thickness can be significantly lowered, and as the shear rate increases, the viscosity lowers flow characteristics, making it easier to spray coating processes, etc. It can be used and has excellent mechanical properties such as tensile strength and elongation, so that it is possible to improve the quality of a coating agent or various molded articles containing a vinyl chloride-based polymer.

In addition, the method for producing a vinyl chloride-based polymer according to the present invention can be performed through emulsion polymerization in the presence of a certain amount of seed particles, thereby producing a vinyl chloride-based polymer having the above specific particle size distribution.

Therefore, the vinyl chloride-based polymer and the method for producing the same according to the present invention can be easily applied to an industry requiring the same, for example, a vinyl chloride-based resin industry for paste processing.

The following drawings attached to the present specification illustrate specific embodiments of the present invention, and serve to further understand the technical spirit of the present invention together with the above-described content of the present invention, so the present invention is limited to the matters described in those drawings It should not be construed as being limited.
1 is a graph showing the results of comparative analysis of particle size distributions of vinyl chloride polymers of Example 1, Comparative Example 1, and Comparative Example 2 according to an embodiment of the present invention.
2 is a graph showing the result of comparative analysis of the particle size distribution of the vinyl chloride polymers of Examples 1, 3, and 4 according to an embodiment of the present invention.
3 is a graph showing the change in yield stress according to the shear region of the vinyl chloride polymer of Example 1, Comparative Example 1, and Comparative Example 2 according to an embodiment of the present invention.
4 is a graph showing the change in yield stress according to the shear region of the vinyl chloride polymer of Example 1, Comparative Example 3, and Comparative Example 4 according to an embodiment of the present invention.

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

The terms or words used in the present specification and claims should not be construed as being limited to 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.

In the present specification, the peak particle size (D _p ) represents a particle size corresponding to the maximum value in the particle size distribution curve of the particle.

In the present specification, the average particle diameter (D ₅₀ ) may be defined as a particle diameter corresponding to 50% of the accumulated particle weight in the particle size distribution curve of the particles. The average particle diameter (D ₅₀ ) may be measured using, for example, a laser diffraction method. In general, the laser diffraction method can measure a particle diameter of several mm from a submicron region, and can obtain high reproducibility and high resolution results.

The present invention provides a vinyl chloride-based polymer capable of expressing high viscosity characteristics in a low shear region and low viscosity characteristics in a high shear region.

Vinyl chloride-based polymers are being applied in various fields, and are manufactured and used for straight processing or paste processing depending on the field of application. Vinyl chloride-based polymers for paste processing are dispersed in a solvent or plasticizer to produce plastisol, and then are used in various products, such as sealants or automobile underbody coatings, through processes such as spray coating.

At this time, when the viscosity of the vinyl chloride-based polymer is low, the vinyl chloride-based polymer has fluidity after coating and before drying, the coating becomes non-uniform, and the vinyl chloride-based polymer is shallowly formed in a specific area, resulting in defects.

In addition, in order to easily use the vinyl chloride-based polymer for spray coating, it should be able to implement flow characteristics such as a pseudoplastic fluid whose viscosity decreases as the shear rate increases.

Accordingly, the present invention provides a vinyl chloride-based polymer capable of exhibiting high viscosity characteristics in a low shear region or a region in which the shear rate is zero, and exhibiting flow characteristics in which the viscosity decreases as the shear rate increases.

The vinyl chloride-based polymer according to an embodiment of the present invention is a vinyl chloride-based polymer having a bimodal particle size distribution, and 40 to 65 wt% of small-diameter particles having a particle diameter of 0.1 μm to 0.39 μm and a particle diameter of 0.4 μm to 3.0 μm 35 to 60% by weight of phosphorus large-diameter particles.

In addition, the vinyl chloride-based polymer may have a polymerization degree of 800 to 2000. Specifically, the vinyl chloride-based polymer may have a polymerization degree of 1100 to 1400.

Preferably, in the vinyl chloride-based polymer, 47 wt% to 65 wt% of the total amount of the polymer particles may be small-diameter particles, and 35 wt% to 53 wt% of the total amount of the polymer particles may be large-diameter particles, even more preferably 55 wt% to 65 wt% may be S particles, and 35 wt% to 45 wt% of the total amount of the polymer particles may be large-diameter particles. If the large-diameter particles are less than 35% by weight of the total amount of the polymer particles, a problem of increasing the viscosity in the high shear region may occur, and when the large-diameter particles exceed 60% by weight of the total amount of the polymer particles, yield stress and thixo The trophy recovery rate is lowered, and in particular, there may be a problem that the tensile strength and the elongation are significantly lowered.

Specifically, in the vinyl chloride-based polymer according to an embodiment of the present invention, the large-diameter particles may have a particle diameter of 0.4 μm to 1.0 μm. That is, 40% to 65% by weight of the total amount of the polymer particles are particles having a particle diameter of 0.1 μm to 0.39 μm, and 35% to 60% by weight of the total amount of the polymer particles are particles having a particle diameter of 0.4 μm to 1.0 μm may include

In addition, in the vinyl chloride-based polymer, the small-diameter particles may have a peak particle diameter (Dp) of 0.12 μm to 0.3 μm, and the large-diameter particles may have a peak particle diameter (Dp) of 0.5 μm to 0.8 μm.

In the present invention, the particle size distribution, particle size, and peak particle size may be obtained by diluting a vinyl chloride-based polymer in deionized water to 1% by weight to prepare a sample, and then measuring it using a particle size meter (DC24000 UHR, CPS Instrument).

As such, the vinyl chloride-based polymer according to an embodiment of the present invention may have a bimodal particle size distribution divided into small-diameter particles and large-diameter particles.

In addition, the vinyl chloride-based polymer of the present invention has a bimodal particle size distribution as described above, and at the same time includes small-diameter particles and large-diameter particles in the particle size range and content ratio as described above, thereby expressing high viscosity characteristics in the low shear region. and can exhibit low-viscosity properties in the high shear region.

Specifically, the vinyl chloride-based polymer may have a viscosity of 0.5 Pa·s to 1.6 Pa·s at a ^{shear rate of 500 s −1, preferably 0.8 Pa·s to 1.6 Pa·s, and more preferably} may have a viscosity of 1 Pa·s to 1.5 Pa·s.

When the viscosity in the high shear region, such as the shear rate of 500 s ^-1 , exceeds 1.6 Pa s, the viscosity is high and it is difficult to spray when used as a spray coating agent through a robot spray gun or squeezing bottle, etc., and it is not sprayed uniformly. problems may arise.

In addition, the vinyl chloride-based polymer according to an embodiment of the present invention may have a yield stress of 80 to 230 Pa at a ^{shear rate of 10 s −1 .}

Specifically, in the ramp-up step, a yield stress of 80 Pa to 180 Pa, preferably 85 Pa to 160 Pa, and more preferably 130 Pa to 150 Pa ^{at a shear rate of 10 s -1} may have, and in the ramp-down step, a shear rate of 10 s ^-1 at a shear rate of 130 Pa to 230 Pa, preferably 140 Pa to 220 Pa, more preferably 180 Pa to 215 Pa. can Here, the ramp-up step ^{means a step of increasing the shear rate from 10 to 500 s -1} for 120 seconds, and the ramp-down step means a step of lowering the ^{shear rate from 500 to 10 s -1 for 120 seconds.} .

The yield stress of the polymer is a physical property that can be correlated with the viscosity properties of the polymer, and may indicate that the higher the yield stress of the polymer, the higher the viscosity. Therefore, the high value of the yield stress at the shear rate of 10 s ^-1 may indicate that the high viscosity characteristic in the low shear region.

At this time, the rheological properties such as viscosity characteristics and yield stress according to the shear rate of the vinyl chloride polymer were mixed with 100 g of the vinyl chloride polymer and 120 g of dioctyl phthalate using a WERKE mixer (EUROSTAR IKA) at 800 rpm for 10 minutes. The plastisol was prepared by stirring, and it may be measured using a Rheometer (AR2000EX peltier plate, TA Instruments) with a measuring tool 40 mm parallel plate and a measuring gap of 500 μm. That is, the viscosity characteristic of the vinyl chloride-based polymer may represent the viscosity characteristic of a plastisol containing the vinyl chloride-based polymer, and the viscosity characteristic may be expressed from the vinyl chloride-based polymer.

In addition, the vinyl chloride-based polymer according to an embodiment of the present invention may have a tensile strength of 4.5 Mpa to 6.5 MPa, preferably 5.0 MPa to 6.0 MPa, and even more preferably 5.3 MPa to 6.0 MPa.

In addition, the vinyl chloride-based polymer according to an embodiment of the present invention may have an elongation of 200% to 400%, preferably 250% to 350%, and even more preferably 280% to 330%.

The tensile strength and elongation may be mechanical properties obtainable by having the aforementioned particle size distribution. Since the vinyl chloride-based polymer of the present invention satisfies the above tensile strength and elongation, it is possible to improve the quality of the coating agent or various molded articles due to excellent mechanical properties during processing into a coating agent or other various molded articles.

At this time, the tensile strength and elongation of the vinyl chloride-based polymer were obtained by stirring 100 g of the vinyl chloride-based polymer and 120 g of dioctyl phthalate using a WERKE mixer (EUROSTAR IKA) at 800 rpm for 10 minutes to prepare a plastisol. It may be measured using a universal material testing machine (UTM) after coating it to a thickness of 2 mm and melting it at 140 °C for 20 minutes in a MATHIS OVEN. That is, the mechanical properties of the vinyl chloride-based polymer may represent the mechanical properties of a plastisol containing the vinyl chloride-based polymer, and the mechanical properties may be expressed from the vinyl chloride-based polymer.

On the other hand, the vinyl chloride-based polymer may be prepared by the production method described later using a vinyl chloride-based monomer, whereby a vinyl chloride-based polymer having the above-described particle size distribution can be obtained.

The vinyl chloride monomer may mean a vinyl chloride monomer alone or a mixture of a vinyl chloride monomer and a vinyl monomer copolymerizable therewith. That is, the vinyl chloride-based polymer according to an embodiment of the present invention may be a vinyl chloride homopolymer or a copolymer of a vinyl chloride monomer and a vinyl-based monomer copolymerizable therewith. If the vinyl chloride-based polymer is the copolymer, 50% or more of vinyl chloride may be included.

The vinyl-based monomer copolymerizable with the vinyl chloride monomer is not particularly limited, but, for example, olefin compounds such as ethylene, propylene, butene, and vinyl esters such as vinyl acetate, vinyl propionate, and vinyl stearate. , unsaturated nitriles such as acrylonitrile, vinyl alkyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl octyl ether, and vinyl lauryl ether, vinylidene halides such as vinylidene chloride, acrylic acid, methacrylic acid Unsaturated fatty acids such as acid, itaconic acid, maleic acid, fumaric acid, maleic anhydride, and itaconic anhydride, and unsaturated fatty acid esters such as anhydrides of these fatty acids, methyl acrylate, ethyl acrylate, monomethyl maleate, dimethyl maleate, and butylbenzyl maleate ), cross-linkable monomers such as diallyl phthalate, and the like, and the vinyl-based monomers may be used alone or in combination of two or more.

In addition, the present invention provides a method for producing the vinyl chloride-based polymer.

The method for producing the vinyl chloride-based polymer according to an embodiment of the present invention may include emulsion polymerization of a vinyl chloride-based monomer in the presence of seed particles (step A).

Specifically, the emulsion polymerization of step A is a step for preparing a vinyl chloride-based polymer, and may be performed by adding a vinyl chloride-based monomer to a polymerization reactor filled with the first seed particle and a polymerization initiator and reacting.

The first seed particle may have an average particle diameter (D ₅₀ ) of 0.1 μm to 0.4 μm, preferably 0.1 μm to 0.3 μm, more preferably 0.15 μm to 0.25 μm, 0.35 to 100 parts by weight of the vinyl chloride monomer. It may be used in an amount of from 0.35 parts by weight to 0.9 parts by weight, preferably from 0.35 parts by weight to 0.7 parts by weight, more preferably from 0.38 parts by weight to 0.65 parts by weight. If the first seed particle is used outside the above range, the particle size distribution of the finally prepared vinyl chloride-based polymer may not exhibit the desired characteristics, and as a result, high viscosity characteristics in the low shear region and high shear region may not be able to exhibit low-viscosity properties.

In the polymerization reactor filled with the first seed particle and the polymerization initiator, the second seed particle is added to more than 0 parts by weight and not more than 0.6 parts by weight, preferably more than 0 parts by weight and not more than 0.5 parts by weight, based on 100 parts by weight of the vinyl chloride-based monomer. Preferably, 0.05 to 0.45 parts by weight may be additionally added. As confirmed from the input amount, even if the second seed particle is not additionally added, it is included in the scope of the present invention.

Here, the second seed particle may have an average particle diameter (D ₅₀ ) of 0.1 μm to 1.0 μm, preferably 0.2 μm to 0.8 μm, and even more preferably 0.4 μm to 0.8 μm.

If the second seed particle is used out of the above range, the particle size distribution of the finally prepared vinyl chloride-based polymer cannot exhibit the desired properties, and as a result, it exhibits high viscosity properties in the low shear region and high shear region may not be able to exhibit low-viscosity properties.

In the present invention, the first seed particle and the second seed particle may be different materials, and the first and second expressions may be used to distinguish different seed particles from each other.

On the other hand, the first seed particle and the second seed particle may be prepared by introducing a vinyl chloride monomer to a polymerization reactor and emulsion polymerization. Specifically, the first seed particle and the second seed particle may be independently prepared, and 100 parts by weight of the vinyl chloride monomer and 0.01 to 5 parts by weight of the primary emulsifier are added to the polymerization reactor filled with the polymerization initiator. and emulsion polymerization at a temperature of 30 ° C to 70 ° C. If necessary, a homogenization process before emulsion polymerization may be performed.

In addition, if necessary, after the polymerization reaction is started, 1 part by weight to 10 parts by weight of the secondary emulsifier may be continuously added for 1 to 10 hours while proceeding with the polymerization reaction.

Here, the polymerization initiator may be any one or more of polymerization initiators to be described later.

In addition, parts by weight of the primary emulsifier and the secondary emulsifier may be parts by weight based on 100 parts by weight of the vinyl chloride-based monomer.

In the present invention, the primary emulsifier and the secondary emulsifier may be different materials or the same material, and when the primary and secondary emulsifiers are the same material, the expression of the primary and secondary emulsifiers depends on the order of input of the emulsifier. It may be to differentiate

The polymerization reactor filled with the polymerization initiator may represent a polymerization reactor containing a mixed solution containing the polymerization initiator, and the polymerization reactor filled with the first seed particle and the polymerization initiator includes the first seed particle and the polymerization initiator may represent a polymerization reactor containing a mixed solution, and the mixed solution may further include polymerization water, a reaction inhibitor and a dispersant in addition to the polymerization initiator, but is not limited thereto.

The polymerization initiator may be used in an amount of 0.01 parts by weight to 2.0 parts by weight based on 100 parts by weight of the vinyl chloride-based monomer. The polymerization initiator is not particularly limited, but may be, for example, at least one selected from the group consisting of peroxy carbonates, peroxy esters, and azo compounds. Specifically, the polymerization initiator is lauryl peroxide (LPO), di-2-ethylhexyl peroxycarbonate (OPP), diisopropyl peroxy dicarbonate, t-butyl peroxypivalate, t-butyl peroxy Neodecanoate, 2,2-azobisisobutyronitrile, etc. may be used alone, or two or more may be used in combination.

In addition, the polymerization initiator may be a water-soluble initiator. When the polymerization initiator is a water-soluble initiator, it is not particularly limited, but may be, for example, at least one selected from the group consisting of potassium persulfate, ammonium persulfate, and hydrogen peroxide.

The reaction inhibitor is not particularly limited, for example, paraquinone, hydroquinone, butylated hydroxy toluene, monomethyl ether hydroquinone, quaternary butyl catechol, diphenyl amine, triisopropanol amine, triethanol amines and the like can be used. In addition, the dispersing agent is not particularly limited, for example, higher alcohols such as lauryl alcohol, myristic alcohol, stearyl alcohol, or higher fatty acids such as lauryl acid, myristic acid, palmitic acid, and stearic acid can be used. have.

The emulsifier, the primary emulsifier and the secondary emulsifier are each independently sodium lauryl sulfate, lauryl benzene sulfonic acid, alpha-olefin sulfonate, sodium dodecyl benzene sulfonate, sodium lauryl ethoxylated sulfate, sodium octadecyl sulfate , sodium lauryl ether sulfate and straight-chain alkylbenzene sulfonate may be at least one selected from the group consisting of, but is not limited thereto.

The homogenization may be performed by homogenizing for 1 hour to 3 hours using a homogenizer at a temperature of 30 °C or less, specifically 5 °C to 25 °C. In this case, the homogenizer is not particularly limited and a conventional one known in the art may be used, for example, a rotor-stator type homogenizer may be used.

The vinyl chloride monomer used in the emulsion polymerization of step A, the first seed particle, and the vinyl chloride monomer used in the second seed particle may be the same material, and the vinyl chloride monomer is the vinyl chloride monomer as described above. It may be a monomer or a combination of a vinyl chloride monomer and a vinyl-based monomer copolymerizable therewith. Specific types of the vinyl-based monomer may be the same as described above.

In addition, in the emulsion polymerization of step A, the filled polymerization initiator may specifically include a water-soluble polymerization initiator, and may further include a first emulsifier, a second emulsifier, and polymerization water as necessary. In this case, the first emulsifier and the polymerization water may be added before introducing the vinyl chloride-based monomer into the reactor in which the seed particles and the polymerization water are mixed, and the second emulsifier may be continuously added after the polymerization is started. have.

Here, the first emulsifier, the second emulsifier, the water-soluble polymerization initiator, and the polymerization water are the primary emulsifier, the secondary emulsifier, the polymerization initiator and the polymerization water used in the step of preparing the first or second seed particles, respectively. can be the same.

The polymerization water may be used in an amount of 70 to 120 parts by weight based on 100 parts by weight of the vinyl chloride-based monomer, and the polymerization water may be deionized water.

In the emulsion polymerization of step A, the water-soluble polymerization initiator may be used in an amount of 0.01 to 2.0 parts by weight based on 100 parts by weight of the vinyl chloride monomer, but is not limited thereto. The water-soluble polymerization initiator is not particularly limited as described above, but may be, for example, at least one selected from the group consisting of potassium persulfate, ammonium persulfate and hydrogen peroxide.

In the emulsion polymerization of step A, the first emulsifier may be used in an amount of 0.01 to 0.4 parts by weight based on 100 parts by weight of the vinyl chloride-based monomer.

In the emulsion polymerization of step A, the second emulsifier is continuously added after polymerization as described above, and may be used in an amount of 1 to 10 parts by weight based on 100 parts by weight of the vinyl chloride-based monomer.

In the emulsion polymerization of step A in the present invention, the first emulsifier and the second emulsifier may be different materials or the same material, and when the first emulsifier and the second emulsifier are the same material, the first and second expressions may be for distinguishing the order of input of the emulsifier.

Specifically, the first emulsifier and the second emulsifier are each sodium lauryl sulfate, lauryl benzene sulfonic acid, alpha-olefin sulfonate, sodium dodecyl benzene sulfonate, sodium lauryl ethoxylated sulfate, sodium octadecyl sulfate, It may be at least one selected from the group consisting of sodium lauryl ether sulfate and linear alkylbenzene sulfonate.

On the other hand, in the emulsion polymerization of step A according to an embodiment of the present invention, additives such as a dispersant and a reaction inhibitor may be further used if necessary, and each of the dispersant and the reaction inhibitor is prepared for the first and second seed particles described above It may be the same as the dispersant and reaction inhibitor used in

The manufacturing method according to an embodiment of the present invention may further include at least one or more steps of washing, coagulation and drying after the emulsion polymerization of step A. The drying is not particularly limited and may be performed by a method commonly known in the art.

In addition, the present invention provides a plastisol comprising the above-mentioned vinyl chloride-based polymer.

The plastisol according to an embodiment of the present invention is 40 parts by weight to 180 parts by weight, preferably 80 parts by weight to 160 parts by weight, even more preferably 100 to 140 parts by weight based on 100 parts by weight of the vinyl chloride-based polymer. It may further include a plasticizer, and, if necessary, may further include additives such as a dispersion diluent, a heat stabilizer, a viscosity modifier and a foaming agent.

The term "plastisol" used in the present invention refers to a mixture of a resin and a plasticizer so that it can be molded, molded or processed into a continuous film by heating, for example, a vinyl chloride polymer and a plasticizer are mixed. It may be in the form of a paste.

The term “plasticizer” used in the present invention may refer to an organic additive material that serves to improve the moldability of the resin at high temperature by adding it to the thermoplastic resin to increase the thermoplasticity.

As the plasticizer and additive, those commonly known in the art may be used.

The plastisol according to an embodiment of the present invention may exhibit the viscosity and mechanical properties as described above by including the vinyl chloride-based polymer having a specific particle size distribution characteristic.

Hereinafter, the present invention will be described in more detail by way of Examples and Experimental Examples. However, the following Examples and Experimental Examples are intended to illustrate the present invention, and the scope of the present invention is not limited thereto.

Example

Preparation Example 1

230 kg of deionized water, 184 g of sodium lauryl sulfate (SLS), and 110 g of potassium persulfate (KPS) were put into a 500 L high-pressure reactor, and then a vacuum was applied while stirring. After 185 kg of vinyl chloride monomer was put into the reactor in a vacuum state, the temperature of the reactor was raised to 56 °C to carry out polymerization. When the polymerization reaction started, 11.1 kg of sodium lauryl sulfate (SLS) was continuously introduced into the reactor for 5 hours. And when the pressure of the reactor ^{reached 4 kg/cm 2} , the reaction was terminated, unreacted vinyl chloride monomer was recovered and removed, and then, vinyl chloride-based first seed particles having an average particle diameter of 0.2 μm were obtained.

Preparation 2

73 kg of deionized water, 1.21 kg of LPO (Lauryl peroxide), and 0.9 g of paraquinone were put into a 200 L high-pressure reactor, and then a vacuum was applied to the reactor at -730 mmHg. 66 kg of vinyl chloride monomer and 7.8 kg of sodium dodecyl benzene sulfonate were added to the reactor in a vacuum state, followed by stirring for 15 minutes. The temperature of the reactor was lowered to 20 °C or less, and homogenization was performed for 2 hours using a rotor-stator type homogenizer. When the homogenization was completed, the temperature of the reactor was raised to 42 °C to carry out polymerization. After 558 minutes, when the pressure of the reactor ^{reached 3.5 kg/cm 2} , the reaction was terminated, and unreacted monomers were recovered and removed to obtain second seed particles.

Example 1

In a 500 liter high-pressure reactor, 180 kg of polymerization water, 116 g of sodium lauryl sulfate, 110 g of potassium persulfate (KPS) and 720 g (0.4 parts by weight) of the first seed particle of Preparation Example 1 compared to 100 parts by weight of the vinyl chloride monomer After adding, vacuum is applied to the reactor while stirring. After 180 kg of vinyl chloride monomer was put into the reactor in a vacuum state, the temperature of the reactor was raised to 54° C. to carry out polymerization. When the polymerization reaction was initiated, 18 kg of sodium lauryl sulfate was continuously introduced into the reactor for 6 hours. Thereafter, when the pressure of the reactor ^{reached 4.0 kg/cm 2} , the reaction was terminated, and unreacted vinyl chloride monomer was recovered and removed to prepare a vinyl chloride polymer. The peak particle diameter of the small-diameter particles of the vinyl chloride polymer is 0.22 μm, the content ratio of the small-diameter particles is 62.4% by weight relative to 100% by weight of the total polymer, the peak particle diameter of the large-diameter particles is 0.66 μm, and the content ratio of the large-diameter particles is 37.6% by weight based on 100% by weight of the total polymer.

In Examples and Comparative Examples of the present invention, small-diameter particles mean particles having a particle diameter in a range of 0.1 μm to 0.39 μm, and large-diameter particles mean particles having a particle diameter in a range of 0.4 μm to 1.0 μm.

Example 2

A vinyl chloride polymer was prepared in the same manner as in Example 1, except that 720 g (0.4 parts by weight) of the second seed particle of Preparation Example 2 was additionally added when preparing the vinyl chloride polymer. The distribution amount according to the particle size of the vinyl chloride-based polymer is shown in Table 1 below. The peak particle diameter of the small-diameter particles of the vinyl chloride polymer is 0.24 μm, the content ratio of the small-diameter particles is 41.5% by weight relative to 100% by weight of the total polymer, the peak particle diameter of the large-diameter particles is 0.68 μm, and the content ratio of the large-diameter particles is 58.5% by weight based on 100% by weight of the total polymer.

Example 3

A vinyl chloride polymer was prepared in the same manner as in Example 1, except that 360 g (0.2 parts by weight) of the second seed particle of Preparation Example 2 was additionally added when preparing the vinyl chloride polymer. The peak particle diameter of the small-diameter particles of the vinyl chloride polymer is 0.26 μm, the content ratio of the small-diameter particles is 51.6% by weight relative to 100% by weight of the total polymer, the peak particle diameter of the large-diameter particles is 0.68 μm, and the content ratio of the large-diameter particles is 48.4% by weight based on 100% by weight of the total polymer.

Example 4

A vinyl chloride polymer was prepared in the same manner as in Example 1, except that 180 g (0.1 parts by weight) of the second seed particle of Preparation Example 2 was additionally added when preparing the vinyl chloride polymer. The peak particle diameter of the small-diameter particles of the vinyl chloride polymer is 0.25 μm, the content ratio of the small-diameter particles is 57.6% by weight relative to 100% by weight of the total polymer, the peak particle diameter of the large-diameter particles is 0.69 μm, and the content ratio of the large-diameter particles is 42.4% by weight based on 100% by weight of the total polymer.

Example 5

A vinyl chloride polymer was prepared in the same manner as in Example 1, except that 1080 g (0.6 parts by weight) of the first seed particle was added during the preparation of the vinyl chloride polymer. The peak particle diameter of the small-diameter particles of the vinyl chloride polymer is 0.24 μm, the content ratio of the small-diameter particles is 47.8% by weight relative to 100% by weight of the total polymer, the peak particle diameter of the large-diameter particles is 0.69 μm, and the content ratio of the large-diameter particles is 52.2% by weight based on 100% by weight of the total polymer.

Comparative Example 1

A vinyl chloride polymer was prepared in the same manner as in Example 1, except that the first seed particle was not added during the preparation of the vinyl chloride polymer. The vinyl chloride polymer has a unimodal particle distribution with a peak particle diameter of 0.282 μm.

Comparative Example 2

1) Preparation of first seed particles

73 kg of deionized water, 1.21 kg of lauryl peroxide (LPO), and 0.9 g of paraquinone were put into a 200 liter high-pressure reactor, and a vacuum was applied to -730 mmHg. In a vacuum reactor, 66 kg of vinyl chloride monomer and 7.8 kg of sodium dodecyl benzene sulfonate were added, and the mixture was stirred for 15 minutes. The internal temperature of the reactor was lowered to 20° C. or less, and homogenization was performed for 2 hours using a rotor-stator type homogenizer. After homogenization was completed, the internal temperature of the reactor was adjusted to 42 ℃ and polymerization was carried out. After 558 minutes, when the pressure of the reactor ^{reached 3.5 kg/cm 2} , the reaction was terminated, the unreacted vinyl chloride monomer was recovered and removed, and the average particle diameter was 0.6 Seed particles of μm were obtained.

2) Preparation of second seed particles

230 kg of deionized water, 1 kg of a first emulsifier (790 g of lauric acid/240 g of NaOH), and 110 g of potassium persulfate (KPS) were put into a 500 liter high-pressure reactor, and then a vacuum was applied to the reactor while stirring. After 185 kg of vinyl chloride monomer was put into the reactor in a vacuum state, the temperature of the reactor was raised to 56 °C to initiate polymerization. After initiating polymerization, 11.1 kg of a second emulsifier (sodium dodecyl benzene sulfonate) was continuously introduced into the reactor for 5 hours. And when the pressure of the reactor ^{reached 4 kg/cm 2} , the reaction was terminated, the unreacted vinyl chloride monomer was recovered and removed, and a second seed having an average particle diameter of 0.12 μm was obtained.

3) Preparation of vinyl chloride polymer

170 kg of polymerization water, 22 kg of first seed particles having an average particle diameter of 0.6 μm, and 14 kg of second seed particles having an average particle diameter of 0.12 μm were put into a 500 liter high-pressure reactor, and a vacuum was applied to the reactor while stirring. After putting 185 kg of vinyl chloride monomer into the reactor in a vacuum state, the temperature of the reactor was raised to 58 °C, and seed emulsion polymerization was performed. When the polymerization reaction started, 7 kg of sodium lauryl sulfate was continuously introduced into the reactor. And when the pressure of the reactor ^{reached 4 kg/cm 2} after 300 minutes, the reaction was terminated, and unreacted vinyl chloride monomer was recovered and removed to prepare a vinyl chloride polymer. The peak particle diameter of the small-diameter particles of the vinyl chloride polymer is 0.26 μm, the content ratio of the small-diameter particles is 34.1% by weight relative to 100% by weight of the total polymer, the peak particle diameter of the large-diameter particles is 1.20 μm, and the content ratio of the large-diameter particles is 65.89% by weight relative to 100% by weight of the total polymer.

Comparative Example 3

A vinyl chloride polymer was prepared in the same manner as in Example 1, except that 2250 g (1.25 parts by weight) of the first seed particle was added during the preparation of the vinyl chloride polymer. The peak particle diameter of the small-diameter particles of the vinyl chloride polymer is 0.16 μm, the content ratio of the small-diameter particles is 17.5% by weight relative to 100% by weight of the total polymer, the peak particle diameter of the large-diameter particles is 0.62 μm, and the content ratio of the large-diameter particles is 81.5% by weight relative to 100% by weight of the total polymer.

Comparative Example 4

A vinyl chloride polymer was prepared in the same manner as in Example 1, except that 1440 g (0.8 parts by weight) of the second seed particle of Preparation Example 2 was additionally added when preparing the vinyl chloride polymer. The peak particle diameter of the small-diameter particles of the vinyl chloride polymer is 0.21 μm, the content ratio of the small-diameter particles is 26.4% by weight relative to 100% by weight of the total polymer, the peak particle diameter of the large-diameter particles is 0.71 μm, and the content ratio of the large-diameter particles is 73.6% by weight relative to 100% by weight of the total polymer.

Comparative Example 5

A vinyl chloride polymer was prepared in the same manner as in Example 1, except that 180 g (0.1 parts by weight) of the first seed particle was added during the preparation of the vinyl chloride polymer. The peak particle diameter of the small-diameter particles of the vinyl chloride polymer is 0.22 μm, the content ratio of the small-diameter particles is 89.2% by weight relative to 100% by weight of the total polymer, the peak particle diameter of the large-diameter particles is 0.65 μm, and the content ratio of the large-diameter particles is 10.8% by weight based on 100% by weight of the total polymer.

Comparative Example 6

A vinyl chloride polymer was prepared in the same manner as in Example 1, except that 540 g (0.3 parts by weight) of the first seed particle was added during the preparation of the vinyl chloride polymer. The peak particle diameter of the small-diameter particles of the vinyl chloride polymer is 0.23 μm, the content ratio of the small-diameter particles is 64.4% by weight relative to 100% by weight of the total polymer, the peak particle diameter of the large-diameter particles is 0.66 μm, and the content ratio of the large-diameter particles is 33.6% by weight relative to 100% by weight of the total polymer.

Comparative Example 7

A vinyl chloride polymer was prepared in the same manner as in Example 1, except that 1800 g (1.0 parts by weight) of the first seed particle was added during the preparation of the vinyl chloride polymer. The peak particle diameter of the small-diameter particles of the vinyl chloride polymer is 0.16 μm, the content ratio of the small-diameter particles is 24.5% by weight relative to 100% by weight of the total polymer, the peak particle diameter of the large-diameter particles is 0.63 μm, and the content ratio of the large-diameter particles is 75.5% by weight based on 100% by weight of the total polymer.

Experimental Example 1: Evaluation of plastisol formulation properties

In order to compare and analyze the viscosity and flow characteristics of each of the vinyl chloride-based polymers prepared in Examples 1 to 5 and Comparative Examples 1 to 7, the viscosity and flow characteristics according to the shear rate of each vinyl chloride polymer were measured. analyzed. The results are shown in Table 1 and FIGS. 1 to 4 below.

First, 100 g of each of the vinyl chloride-based polymers and 120 g of dioctyl phthalate (DOP) were stirred at 800 rpm for 10 minutes using a Werke mixer (EUROSTAR IKA) to prepare each plastisol. The viscosity and flow properties and mechanical properties of the were evaluated in the following way.

1) Viscosity and flow characteristics analysis

Each of the plastisols was measured for fluidity and viscosity using a Rheometer (AR2000EX peltier plate, TA Instruments) with a measuring tool 40 mm parallel plate and a measuring gap of 500 μm. At this time, the measurement is the ^{first step of adjusting the shear rate to 10 s -1} for 30 seconds (preliminary shearing step), the ^{second step of raising the shear rate from 10 s -1} to 500 s ^-1 for 120 seconds (ramp-up step) , 3 steps (holding step) of maintaining the shear rate at 500 s ^-1 for 180 seconds and 4 steps (ramp-down step) of lowering the ^{shear rate from 500 s -1} to 10 s ^{-1 for 120 seconds were performed.} .

2) Analysis of mechanical properties

After preparing a plastisol in the same manner as in 2) above, it was coated with a thickness of 2 mm, melted in a Matisse oven at 140° C. for 20 minutes, and then tensile strength and elongation were measured using a universal testing machine (UTM).

division yield stress
(at 10 s ^-1 , Pa) Thixotropy
recovery rate (%) Viscosity
(at 500 s ^-1 , Pa s) The tensile strength
(MPa) elongation
(%) Step 2 (ramp-up) Step 4 (ramp-down) Example 1 146 212 146 1.037 5.84 320 Example 2 149 179 122 1.49 5.10 284 Example 3 132 183 138 1.331 5.21 289 Example 4 135 198 146 1.114 5.54 294 Example 5 86 152 176 1.12 5.49 288 Comparative Example 1 60 27 45 1.746 5.94 335 Comparative Example 2 10 7 70 0.587 4.21 203 Comparative Example 3 157 44 28 1.723 3.23 174 Comparative Example 4 137 184 135 2.396 4.42 219 Comparative Example 5 152 289 190 2.105 5.88 325 Comparative Example 6 147 206 140 1.758 5.78 315 Comparative Example 7 146 53 36.3 1.765 3.31 180

As shown in Table 1 and FIGS. 3 and 4, the plastisol containing the vinyl chloride-based polymer of Examples 1 to 5 according to the present invention was prepared by mixing the vinyl chloride-based polymer of Comparative Examples 1 to 7 according to the present invention. It can be seen that low viscosity characteristics can be realized at high shear compared to plastisol, and the tensile strength and elongation are excellent, and the yield stress in the low shear region has a high value.

Specifically, Comparative Example 1, in which particles having a particle diameter in the range of 0.4 μm to 1.0 μm in the vinyl chloride-based polymer does not exist, has a yield stress in the low shear region and 4 steps in 2 steps (ramp-up) compared to Examples 1 to 5. (ramp-down) It can be seen that the yield stress in the low shear region is low, the viscosity in the high shear region is remarkably high, and the thixotropy shows a very low recovery rate.

In addition, Comparative Examples 2 to 4 and Comparative Example 7, in which the particle ratio of the particle diameter in the range of 0.4 μm to 1.0 μm in the vinyl chloride-based polymer exceeds 60% by weight, is also low in 2 steps (ramp-up) compared to Examples 1 to 5 Yield stress in the shear region and yield stress in the 4 step (ramp-down) low shear region are low, and the viscosity in the high shear region is very high. can be seen falling.

In addition, it can be seen that Comparative Examples 5 and 6, in which the particle ratio of the vinyl chloride-based polymer has a particle size in the range of 0.4 μm to 1.0 μm, is less than 35% by weight, has a higher viscosity in the high shear region than Examples 1 to 5.

As described above, Comparative Examples 1 to 7 have a high viscosity in the high shear region, whereas the yield stress in the low shear region has a remarkably low value in some comparative examples, so it is not easy to spray when used as a coating agent, Even if applied, the thickness of the coating becomes non-uniform, which may cause defects, and the thixotropy recovery rate has a very low value or has a large difference compared to the optimal standard of 100% in some comparative examples, so fluidity changes It may cause a problem in that it is not easy to use as a cursor coating agent.

In addition, in the case of Comparative Examples 2 to 4 and Comparative Example 7, it can be seen that the mechanical properties are not good because the tensile strength and the elongation is lowered.

In contrast, Examples 1 to 5 generally show high levels in each of the yield stress in the low shear region of the second stage and the yield stress in the low shear region of the fourth stage, but the reduction in the yield stress in the fourth stage low shear region is not large, so thixotropy The recovery rate was excellent, and it showed excellent low-viscosity properties in the high shear region, and mechanical properties such as tensile strength and elongation also had improved values.

This means that each of the vinyl chloride polymers of Examples 1 to 5 can have mechanical properties along with flow properties and viscosity properties as described above by exhibiting particle distribution properties according to the present invention.

In addition, this can also be confirmed through FIGS. 3 and 4, specifically, in the rheological property graph of Example 1 and Comparative Examples 1 and 2 of FIG. 3, in the low shear rate region, the y-axis value of Example 1 That is, it can be confirmed that the value of the yield stress is higher than that of Comparative Examples 1 and 2, and in the high shear rate region, it can be confirmed that the slope of the graph of Example 1, that is, the viscosity is lower than that of Comparative Examples 1 and 2 can Also in Figure 4, it can be seen that the value of the yield stress (y-axis value of the graph) of Example 1 is higher than that of Comparative Examples 3 and 4 in the low shear rate region, and in the high shear rate region, the viscosity of Example 1 (of the graph) It can be seen that the value of the slope) is lower than those of Comparative Examples 3 and 4.

On the other hand, the particle distribution characteristics of Examples and Comparative Examples can also be confirmed through FIGS. 1 and 2, and FIGS. 1 and 2 are graphs showing the particle distribution of Examples and Comparative Examples, and the particle weight ratio according to the particle size was shown. , at this time, the relative weight ratio of particles was shown using the highest point as 100%. The difference between the particle distribution of the polymer according to the embodiment of the present invention and the particle distribution of the comparative example can be confirmed.

As such, the vinyl chloride-based polymer according to the present invention can exhibit high viscosity characteristics in a low shear region and low viscosity characteristics in a high shear region, so that it is easy to process paste, including spray coatings such as automotive underbody coatings or sealant coatings. can be used

Claims (13)

In the method for producing a vinyl chloride polymer comprising emulsion polymerization of a vinyl chloride monomer in the presence of first seed particles having an average particle diameter (D _{50 ) of 0.1 μm to 0.4 μm,}
The first seed particle is present in an amount of 0.35 to 0.9 parts by weight based on 100 parts by weight of the vinyl chloride-based monomer,
The vinyl chloride-based polymer,
40 to 65 wt% of small-diameter particles having a particle diameter of 0.1 μm to 0.39 μm; and
35 to 60% by weight of large-diameter particles having a particle diameter of 0.4 μm to 3.0 μm; Method for producing a vinyl chloride-based polymer comprising a.
According to claim 1,
The vinyl chloride-based polymer is 55 wt% to 65 wt% of the small-diameter particles; and 35 wt% to 45 wt% of the large-diameter particles.
According to claim 1,
The method for producing a vinyl chloride-based polymer that the large-diameter particles have a particle diameter of 0.4 μm to 1.0 μm.
According to claim 1,
The vinyl chloride-based polymer,
A method for producing a vinyl chloride-based polymer having a peak particle diameter (Dp) of 0.12 μm to 0.3 μm of the small-diameter particles.
According to claim 1,
The vinyl chloride-based polymer,
A method for producing a vinyl chloride-based polymer having a peak particle diameter (Dp) of 0.5 μm to 0.8 μm of the large-diameter particles.
delete delete delete According to claim 1,
A method for producing a vinyl chloride-based polymer by further adding a second seed particle in the step of emulsion polymerization of the vinyl chloride-based monomer.
10. The method of claim 9,
The second seed particle is a method for producing a vinyl chloride-based polymer comprising more than 0 parts by weight and 0.6 parts by weight or less based on 100 parts by weight of the vinyl chloride-based monomer.
10. The method of claim 9,
The second seed particles have an average particle diameter (D ₅₀ ) of 0.1 to 1.0 μm, a method for producing a vinyl chloride-based polymer.
10. The method of claim 9,
The weight ratio of the first seed particle and the second seed particle is 1:1 to 4:1. delete

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