Name of the invention: Vinyl chloride polymer and its manufacturing method
Technical field
[One]
[Mutual citation with related application]
[2]
This application claims the interest of priority based on Korean Patent Application No. 10-2018-0113823 filed on September 21, 2018 and Korean Patent Application No. 10-2019-0094160 filed on August 02, 2019, and has applied for the corresponding Korean patent. All contents disclosed in the literature of are included as part of this specification.
[3]
[Technical field]
[4]
The present invention relates to a vinyl chloride-based polymer having excellent blending properties and improved processability by controlling the surface non-uniformity of particles, and a method for producing the same.
[5]
Background
[6]
Vinyl chloride-based polymers are polymers containing 50% or more of vinyl chloride, and are inexpensive, easy to control hardness, and can be applied to most processing machines, so their application fields are diverse. In addition, it is possible to provide a molded article having excellent physical and chemical properties, such as mechanical strength, weather resistance, and chemical resistance, and thus is widely used in various fields.
[7]
On the other hand, the vinyl chloride-based polymer is blended with sub-materials and applied to various fields. In this case, when the surface of the vinyl-chloride-based polymer particles is smooth, the bonding strength with the sub-material is poor, resulting in poor blending properties and poor processability.
[8]
Such vinyl chloride-based polymers are prepared and used through bulk polymerization, suspension polymerization, or emulsion polymerization as desired. Of these, production through bulk polymerization does not require a drying process because it does not use a medium such as water, unlike suspension polymerization or emulsion polymerization, and uses vinyl chloride monomers, initiators, and other reaction additives. It is relatively inexpensive and is widely applied in industry.
[9]
However, most of the vinyl chloride-based polymer particles produced by bulk polymerization have a smooth and angular surface (see Fig. 1), and thus, compared to the vinyl chloride-based polymer prepared by suspension polymerization with a non-uniform surface (see Fig. 2). It is known that the processability is poor due to the low bonding strength with the subsidiary material during the blending process, and the blended product is aggregated.
[10]
[11]
Therefore, in order to further increase the industrial applicability of the vinyl chloride-based polymer produced through block polymerization, which has an advantage in terms of production cost, a method of making the surface of the particles of the vinyl chloride-based polymer produced through block polymerization is required. Actually.
[12]
Detailed description of the invention
Technical challenge
[13]
The present invention has been devised to solve the problems of the prior art, and an object of the present invention is to provide a vinyl chloride-based polymer having excellent processability in which the surface non-uniformity of particles is controlled.
[14]
In addition, an object of the present invention is to provide a method for producing the vinyl chloride-based polymer.
[15]
Means of solving the task
[16]
In order to solve the above problems, the present invention provides a vinyl chloride-based polymer having a particle non-uniformity of 10 or more, defined by the following equation.
[17]
[Equation 1]
[18]

[19]
In Equation 1, X i is the standard deviation of the i-th particle, and is a value defined by Equation 2 below,
[20]
[Equation 2]
[21]

[22]
In Equation 2, A n is a correction value of the n-th measurement diameter of the i-th particle, wherein the correction value is a value defined by Equation 3 below,
[23]
[Equation 3]
[24]

[25]
In Equation 3, D n is the n-th measured diameter of the i-th particle , D 0 is the longest diameter in the i-th particle, and n is an integer from 1 to 50.
[26]
In addition, the present invention comprises the steps of forming particle nuclei by adding a prepolymerization initiator to the first vinyl chloride-based monomer and prepolymerizing at a pressure of 8.0 K/G to 8.7 K/G (Step 1); And post-polymerizing a second vinyl chloride-based monomer and a post polymerization initiator in the presence of the particle nuclei (Step 2), wherein the pre-polymerization initiator is 1.3 K/G to 3.5 K/G compared to the pressure during pre-polymerization. It is added at a low pressure and provides a method for producing the vinyl chloride-based polymer having a particle non-uniformity of 10 or more as defined by Equation 1 above.
[27]
Effects of the Invention
[28]
The vinyl chloride-based polymer according to the present invention can be prepared through the above production method in which the pressure conditions and the time point of the pre-polymerization initiator are adjusted during pre-polymerization, so that the particle non-uniformity can be controlled and have a high porosity. This can be improved and the workability can be excellent.
[29]
In addition, the production method of the vinyl chloride-based polymer according to the present invention controls the pressure during prepolymerization in the prepolymerization step of forming particle nuclei, and a pressure of 1.3 K/G to 3.5 K/G lower than the pressure during prepolymerization of the prepolymerization initiator. The surface of the particle nucleus at the initial stage of the reaction can be adjusted by adding it at the time of 1, and thus a vinyl chloride-based polymer having a controlled particle non-uniformity and porosity can be prepared.
[30]
Accordingly, the method for producing a vinyl chloride-based polymer according to the present invention and the vinyl chloride-based polymer prepared therefrom can be easily applied to industries requiring it, such as vinyl chloride-based resins and molded product-related industries.
[31]
Brief description of the drawing
[32]
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 contents of the above-described invention, so the present invention is limited to the matters described in such drawings. It is limited and should not be interpreted.
[33]
1 is a SEM image of observing particles of a vinyl chloride polymer prepared through conventional block polymerization.
[34]
2 is an SEM image of observing particles of a vinyl chloride polymer prepared through a conventional suspension polymerization.
[35]
Best mode for carrying out the invention
[36]
Hereinafter, the present invention will be described in more detail to aid understanding of the present invention.
[37]
The terms or words used in the specification and claims should not be construed as being limited to their usual or dictionary meanings, and the inventor may appropriately define the concept of terms in order to describe his own invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of ​​the present invention based on the principle that there is.
[38]
The terms'first vinyl chloride-based monomer' and'second vinyl chloride-based monomer' used in the present invention are used to distinguish the order of participation in the reaction, and the substance itself may mean the same vinyl chloride-based monomer.
[39]
The term'particle non-uniformity' used in the present invention refers to the surface non-uniformity of the particle or the roughness of the particle surface, and obtains the standard deviation between diameters in multiple directions for 50 particles in the polymer, and the diameter standard deviation of each of these particles It was defined as the average value of, and the smaller the value, the smaller the standard deviation between the diameters of each particle, that is, the diameters of the multiple directions of the particle have similar values, indicating that the particle is close to a spherical shape, and thus the roughness of the particle surface is low. Or it could mean that it is smooth.
[40]
The unit "K/G (kgf/cm 2 )" used in the present invention is a unit representing pressure, and 1 K/G may be equal to 0.968 atm.
[41]
[42]
The present invention provides a vinyl chloride-based polymer having excellent processability by controlling particle non-uniformity and improving blendability.
[43]
The vinyl chloride-based polymer according to an embodiment of the present invention may be prepared by a method to be described later, so that the roughness of the surface of the particles constituting the polymer may be adjusted, and thus blending properties may be improved and thus processability may be excellent.
[44]
Specifically, the vinyl chloride-based polymer is characterized in that the particle non-uniformity defined by the following equation (1) is 10 or more. More specifically, the vinyl chloride-based polymer may have a particle non-uniformity of 11 or more and 16 or less.
[45]
[Equation 1]
[46]

[47]
In Equation 1, X i is the standard deviation of the i-th particle, and is a value defined by Equation 2 below,
[48]
[Equation 2]
[49]

[50]
In Equation 2, A n is a correction value of the n-th measurement diameter of the i-th particle, wherein the correction value is a value defined by Equation 3 below,
[51]
[Equation 3]
[52]

[53]
In Equation 3, D n is the n-th measured diameter of the i-th particle , D 0 is the longest diameter in the i-th particle, and n is an integer from 1 to 50.
[54]
[55]
In addition, the vinyl chloride-based polymer according to an embodiment of the present invention may have a gelation rate of 50 seconds or more and 80 seconds or less. The vinyl chloride-based polymer according to the present invention may exhibit a gelation rate within the above-described range by having the particle surface non-uniformity described above, and thus may have excellent processability.
[56]
Here, the gelation rate is 50 g of a dry mixture prepared by mixing 2 parts by weight of a heat stabilizer and 2 parts by weight of epoxidized soybean oil to 100 parts by weight of a vinyl chloride-based polymer into a Brabender Torque Rhomixer and melting it at 165° C. at 30 rpm. It is measured by recording the mechanical load that appears.
[57]
In addition, the vinyl chloride-based polymer according to an embodiment of the present invention may have a porosity of 59% or more, and specifically, may be 59 to 65% or 60% to 63%, and mechanical properties decrease within this range. Without the plasticizer, the absorption rate is increased, and thus processability may be excellent.
[58]
Here, the porosity was calculated from the amount of mercury penetrating into each vinyl chloride polymer particle using a mercury porosity analyzer (AutoPore IV 9520, Micromeritics).
[59]
[60]
Meanwhile, the vinyl chloride-based polymer according to an embodiment of the present invention may be a block polymer.
[61]
[62]
In addition, the present invention provides a method for producing a vinyl chloride-based polymer in which the non-uniformity of the particle surface is controlled.
[63]
In general, vinyl chloride-based polymers are manufactured through a method of bulk polymerization, suspension polymerization or emulsion polymerization, and unlike suspension polymerization or emulsion polymerization, bulk polymerization does not use a medium, and only monomers, polymerization initiators, and additives as needed are added. Since it can be polymerized, it is widely used in that it does not require a process after polymerization such as a drying process, so that the production cost is low and mass production is easy. However, in the case of a polymer prepared by bulk polymerization, the surface of the polymer particles is smooth and has a angular shape, and thus there is a problem of poor processability due to poor bonding strength with sub-materials when blended compared to a polymer prepared by suspension polymerization or emulsion polymerization with a rough particle surface.
[64]
Accordingly, the present invention provides a method of preparing a vinyl chloride-based polymer through bulk polymerization, and in which the particle surface shape is adjusted by controlling the timing of the polymerization initiator in the initial stage of polymerization.
[65]
In the method for preparing the vinyl chloride-based polymer according to an embodiment of the present invention, a prepolymerization initiator is added to the first vinyl chloride-based monomer and prepolymerized at a pressure of 8.0 K/G to 8.7 K/G to form particle nuclei. (Step 1); And post-polymerizing a second vinyl chloride-based monomer and a post polymerization initiator in the presence of the particle nuclei (Step 2), wherein the pre-polymerization initiator is 1.3 K/G to 3.5 K/G lower than the pressure during pre-polymerization. It is characterized by adding under pressure.
[66]
The step A is a prepolymerization step for forming a particle nucleus, and may be performed by adding a prepolymerization initiator to the first vinyl chloride-based monomer and prepolymerization, wherein the prepolymerization is 8.0 K/G to 8.7 K/G. The prepolymerization initiator may be performed at pressure, and the prepolymerization initiator may be added at a pressure that is 1.3 K/G to 3.5 K/G lower than the pressure during the prepolymerization, and specifically, the prepolymerization initiator is the pressure during the prepolymerization Compared to 1.5 K/G to 3.0 K/G may be added at a lower pressure.
[67]
In the case of bulk polymerization, since polymerization proceeds in a way that the outer wall of the polymer particles is formed at the beginning of the reaction and the inside of the polymer particles is filled, it is necessary to control the reaction rate at the beginning of the reaction in order to control the surface shape of the final polymer particles. Polymerization is carried out at a pressure controlled in the above specific range, and the prepolymerization initiator is added to the first vinyl chloride-based monomer when the pressure reaches a pressure that is 1.3 K/G to 3.5 K/G lower than that of the prepolymerization pressure. The non-uniformity and porosity can be adjusted to an appropriate level as described above.
[68]
Specifically, in the step A according to the present invention, the first vinyl chloride-based monomer is added to the reactor, and the pressure in the reactor is increased to a predetermined pressure from 8.0 K/G to 8.7 K/G to perform prepolymerization, and the The pre-polymerization initiator may be added when the pressure reaches a pressure lower than the pre-polymerization performing pressure of 1.3 K/G to 3.5 K/G, specifically 1.5 K/G to 3.0 K/G.
[69]
In addition, the prepolymerization initiator may be added in an amount of 0.01 parts by weight to 1 part by weight based on 100 parts by weight of the first vinyl chloride-based monomer, and specifically, may be added in an amount of 0.03 to 0.1 parts by weight. If the prepolymerization initiator is added in the above range, the prepolymerization reaction can be started smoothly and the reaction time can be appropriately adjusted. In addition, since the heat of the reaction agent can be maintained at an appropriate value, a decrease in stability due to the heat of reaction can be prevented, and problems such as a decrease in thermal stability due to a residual initiator can be minimized.
[70]
In addition, the prepolymerization initiator is not particularly limited, but may be used, for example, a compound of peroxyester or peroxydicarbonate, specifically di-2-ethylhexyl peroxycarbonate, t-butylperoxyneode Decanoate, t-butylperoxy ester, cumylperoxy ester, cumylperoxy neodecanoate, 1,1,3,3-tetramethyl butyl peroxy neodecanoate, t-hexyl peroxy neodecanoate , t-hexyl peroxy pivalate, t-butyl peroxy pivalate, di-sec-butyl peroxy dicarbonate, di-2-ethoxyethyl peroxy dicarbonate, isobutyryl peroxide, 3,5,5 -It may be one or more selected from trimethylhexanoyl peroxide, lauryl peroxide, and octylperoxy dicarbonate.
[71]
[72]
In addition, the first vinyl chloride monomer may be a vinyl chloride monomer or a mixture of a vinyl chloride monomer and a vinyl monomer copolymerizable with the vinyl chloride monomer, and the first vinyl chloride monomer is a vinyl chloride monomer and In the case of mixing a vinyl-based monomer, it may be appropriately adjusted and used so that the vinyl chloride is contained in an amount of 50% by weight or more in the vinyl chloride-based polymer prepared through this.
[73]
The vinyl-based monomer is not particularly limited, but, for example, olefin compounds such as ethylene, propylene, and butene; Vinyl esters such as vinyl acetate, vinyl propionate, and vinyl stearate; Unsaturated nitriles such as acrylonitrile; Vinylalkyl ethers such as vinylmethyl ether, vinylethyl ether, vinyloctyl ether, and vinyllauryl ether; Vinylidene halides such as vinylidene chloride; Unsaturated fatty acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, maleic anhydride, and itaconic anhydride, and anhydrides of these fatty acids; Unsaturated fatty acid esters such as methyl acrylate, ethyl acrylate, monomethyl maleate, dimethyl maleate, and butylbenzyl maleate; It may be a crosslinkable monomer such as diallylphthalate, and the like, and the vinyl-based monomer may be used alone or in combination of two or more.
[74]
[75]
Meanwhile, the prepolymerization of step A may be performed up to a polymerization conversion rate of 10% to 15%. Although the polymerization conversion rate of the prepolymerization of step A is not particularly limited, the prepolymerization is a step for preparing particle nuclei, and when the prepolymerization proceeds excessively to form excessive particle nuclei, the properties of the finally produced polymer It can be modified differently from the purpose, and therefore, there is a need to control the degree of polymerization of the prepolymerization. If the prepolymerization is performed up to the polymerization conversion rate, a vinyl chloride-based polymer having a desired degree of non-uniformity can be prepared without excessive formation of particle nuclei, and polymerization degree and other physical properties may not be affected.
[76]
In this case, the polymerization conversion rate indicates the conversion rate of the first vinyl chloride-based monomer to the polymer, and may be measured using a butane tracer equipped with gas chromatography. Specifically, a polymerization conversion rate curve according to the ratio of the vinyl chloride-based monomer to butane over time under certain polymerization conditions may be prepared for each polymerization condition, and the polymerization conversion rate according to the polymerization conditions may be measured based on this. In addition, the polymerization conversion rate may include an error range according to the measurement.
[77]
In addition, the prepolymerization may be performed under a temperature range of 30°C to 70°C.
[78]
[79]
The step B is a step for preparing a vinyl chloride-based polymer by growing the inside of the particle nucleus prepared by the prepolymerization, and a second vinyl chloride-based monomer and a post polymerization initiator in the presence of the particle nucleus prepared in the prepolymerization step Can be carried out by post-polymerization.
[80]
Here, the post polymerization may be performed at a pressure of 6 K/G to 13 K/G.
[81]
The second vinyl chloride-based monomer may be the same as the first vinyl chloride-based monomer.
[82]
The post polymerization initiator may be used in an amount of 0.05 to 2 parts by weight based on 100 parts by weight of the second vinyl chloride monomer, and specifically, may be used in an amount of 0.1 to 0.5 parts by weight.
[83]
In addition, the post polymerization initiator is not particularly limited, but, for example, di-2-ethylhexyl peroxycycarbonate, t-butyl peroxy neodecanoate, t-butyl peroxy ester, cumyl peroxy ester, cumyl peroxy neo Decanoate, 1,1,3,3-tetramethyl butyl peroxy neodecanoate, t-hexyl peroxy neodecanoate, t-hexyl peroxy pivalate, t-butyl peroxy pivalate, di- sec-butyl peroxy dicarbonate, di-2-ethoxyethyl peroxy dicarbonate, isobutyryl peroxide, 3,5,5-trimethylhexanoyl peroxide, lauryl peroxide and octyl peroxy dicarbonate selected from There may be more than one type. Meanwhile, the post polymerization initiator may be the same material as or different from the prepolymerization initiator.
[84]
In addition, the post polymerization may be performed at a temperature range of 30°C to 70°C.
[85]
[86]
On the other hand, the manufacturing method according to an embodiment of the present invention can remove the reactivity of the remaining post polymerization initiator by adding a polymerization inhibitor at the end of the post polymerization, and the polymerization inhibitor is not particularly limited, for example, hydro Quinone, butylated hydroxy toluene, monomethyl ether hydroquinone, quaternary butyl catechol, diphenylamine, triisopropanol amine, triethanol amine, and the like can be used. In addition, the amount of the polymerization inhibitor may be appropriately adjusted according to the amount of the residual post polymerization initiator, but usually 0.001 parts by weight to 0, based on 100 parts by weight of the total vinyl chloride monomers used in the prepolymerization and post polymerization. It can be used in 1 part by weight.
[87]
In addition, in the preparation method, a reaction medium may be used as needed, and an additive such as a molecular weight modifier may be further used.
[88]
The reaction medium is not particularly limited, and a conventional organic solvent may be used. For example, aromatic compounds such as benzene, toluene, and xylene, methyl ethyl ketone, acetone, n-hexane, chloroform, cyclohexane, and the like may be used.
[89]
The molecular weight modifier is not particularly limited, but, for example, n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, and the like may be used.
[90]
[91]
Hereinafter, the present invention will be described in more detail by examples and experimental examples. However, the following Examples and Experimental Examples are for illustrative purposes only, and the scope of the present invention is not limited thereto.
[92]
Example 1
[93]
135 kg of vinyl chloride monomer was added to a prepolymerization reactor having a volume of 0.2 m 3 degassed with high vacuum, and the pressure was raised to 8 K/G while stirring to polymerize to a polymerization conversion rate of 10% to prepare particle nuclei. At this time, when the internal pressure of the reactor reached 6.5 K/G during the elevated pressure, 40 g of di-2-ethyl hexyl peroxydicarbonate (OPP) was added to participate in the reaction.
[94]
Thereafter, 75 kg of vinyl chloride monomer was added to a 0.5 m 3 post polymerization reactor, and the prepared particle nuclei were transferred, and then 1,1,3,3-tetramethyl butyl peroxy 95 g of neodicarbonate (OND) was added, and the pressure was raised while stirring, followed by polymerization at a pressure of 8 K/G for 180 minutes. After polymerization was completed, the unreacted vinyl chloride monomer remaining under vacuum for 30 minutes while stirring was recovered, and a vinyl chloride polymer was prepared.
[95]
[96]
Example 2
[97]
In Example 1, a vinyl chloride polymer was prepared in the same manner as in Example 1, except that di-2-ethyl hexyl peroxydicarbonate was added at the time of reaching 5 K/G.
[98]
[99]
Example 3
[100]
In Example 1, through the same method as in Example 1, except that prepolymerization was carried out at 8.7 K/G, and di-2-ethyl hexyl peroxydicarbonate was added at the point at which 6.7 K/G was reached. A vinyl chloride polymer was prepared.
[101]
[102]
Example 4
[103]
In Example 1, the same method as in Example 1 was used except that 95 g of 1,1,3,3-tetramethyl butyl peroxy neodicarbonate (OND) was added together with a vinyl chloride monomer during post-polymerization. Through the vinyl chloride polymer was prepared.
[104]
[105]
Comparative Example 1
[106]
In Example 1, a vinyl chloride polymer was prepared in the same manner as in Example 1, except that prepolymerization was performed at 12 K/G.
[107]
[108]
Comparative Example 2
[109]
In Example 1, a vinyl chloride polymer was prepared in the same manner as in Example 1, except that di-2-ethyl hexyl peroxydicarbonate was added at the time of reaching 7 K/G, but normal particle nuclei were The polymer was not produced because it was not produced. This is a result that means that the dispersion is insufficient because di-2-ethylhexyl peroxydicarbonate is added late.
[110]
[111]
Comparative Example 3
[112]
In Example 1, a vinyl chloride polymer was prepared in the same manner as in Example 1, except that di-2-ethyl hexyl peroxydicarbonate was added at the time of reaching 4 K/G.
[113]
[114]
Comparative Example 4
[115]
In Example 1, through the same method as in Example 1, except that prepolymerization was carried out at 10 K/G, and di-2-ethyl hexyl peroxydicarbonate was added at the time of reaching 8.5 K/G. A vinyl chloride polymer was prepared.
[116]
[117]
Comparative Example 5
[118]
In Example 1, through the same method as in Example 1, except that pre-polymerization was carried out at 7 K/G and di-2-ethyl hexyl peroxydicarbonate was added at the point of reaching 5.5 K/G. A vinyl chloride polymer was prepared, but the polymer was not produced because normal particle nuclei were not generated. This is a result that means that the pressure was too low during pre-polymerization so that polymerization was not normally performed.
[119]
[120]
Comparative Example 6
[121]
In Example 1, through the same method as in Example 1, except that pre-polymerization was carried out at 10 K/G and di-2-ethyl hexyl peroxydicarbonate was added at the point of reaching 6.5 K/G. A vinyl chloride polymer was prepared.
[122]
[123]
Comparative Example 7
[124]
In Example 1, through the same method as in Example 1, except that prepolymerization was carried out at 9.5 K/G, and di-2-ethyl hexyl peroxydicarbonate was added at the time of reaching 8 K/G. A vinyl chloride polymer was prepared.
[125]
[126]
Comparative Example 8
[127]
In Example 1, a vinyl chloride polymer was prepared in the same manner as in Example 1, except that prepolymerization was performed at 9.5 K/G.
[128]
[129]
Comparative Example 9
[130]
In Comparative Example 1, chlorination was carried out in the same manner as in Comparative Example 1, except that 1,1,3,3-tetramethyl butyl peroxy neodicarbonate was added at the point of reaching 5.5 K/G during post-polymerization. A vinyl polymer was prepared.
[131]
[132]
Comparative Example 10
[133]
In Comparative Example 1, a vinyl chloride polymer was prepared in the same manner as in Comparative Example 1, except that post polymerization was performed at 7 K/G.
[134]
[135]
Experimental Example 1
[136]
The non-uniformity, polymerization degree, and porosity (%) of the surfaces of each of the vinyl chloride polymer particles prepared in Examples 1 to 4 and Comparative Examples 1 to 10 were measured. The results are shown in Table 1 below.
[137]
(1) particle unevenness
[138]
The particle non-uniformity is determined by measuring the longest diameter per particle for a total of 50 particles among particles observed using an optical microscope for each polymer surface, and measuring 50 diameters passing through the center of each of the following Equations 1 to It was calculated through Equation 3. That is, for each 50 particles, the diameter standard deviation of each particle is calculated through Equations 2 and 3 using the longest diameter and 50 diameters passing through the center thereof, and the average of the calculated 50 diameter standard deviations Expressed as a non-uniformity.
[139]
[Equation 1]
[140]

[141]
In Equation 1, Xi is the standard deviation of the i-th particle, and is a value defined by Equation 2 below,
[142]
[Equation 2]
[143]

[144]
In Equation 2, An is a correction value of the n-th measurement diameter of the i-th particle, wherein the correction value is a value defined by Equation 3 below,
[145]
[Equation 3]
[146]

[147]
In Equation 3, D n is the n-th measured diameter of the i-th particle , D 0 is the longest diameter in the i-th particle, and n is an integer from 1 to 50.
[148]
[149]
(2) degree of polymerization
[150]
The degree of polymerization was measured according to ASTM D1 243-49.
[151]
[152]
(3) Porosity (%)
[153]
The porosity was calculated from the amount of mercury penetrating into each vinyl chloride polymer particle using a mercury porosity analyzer (AutoPore IV 9520, Micromeritics).
[154]
[Table 1]
[155]
As shown in Table 1, the vinyl chloride polymers of Examples 1 to 4 according to an embodiment of the present invention all exhibit the same degree of polymerization and have a rough surface with a particle non-uniformity of 10 or more, and an increased porosity. Confirmed. On the other hand, Comparative Example 1, Comparative Example 3, Comparative Example 4, and Comparative Examples 6 to 10 had a smooth surface with a particle non-uniformity of less than 10, and the porosity was also significantly reduced compared to Examples 1 to 4. In addition, in the case of Comparative Example 2 and Comparative Example 5, the polymer was not produced.
[156]
Specifically, in the case of Comparative Examples 1, 4, and 6 to 10, in which polymerization was performed at a pressure higher than 8.7 K/G during pre-polymerization, the degree of non-uniformity was significantly lower compared to Examples 1 to 4, especially Comparative Example 4, In the case of Comparative Example 7 and Comparative Example 8, a polymer having a smooth particle surface was produced even though the prepolymerization initiator was added at a point of 1.5 K/G or 3.0 K/G lower than the pressure during polymerization. This is a result indicating that when the pressure is too high during pre-polymerization, the initial particle appearance is quickly and smoothly formed, indicating that the non-uniformity of the particle surface cannot be adjusted beyond a certain range.
[157]
In addition, in the case of Comparative Example 3, in which the prepolymerization initiator was added at a time of -4 K/G compared to the pressure during prepolymerization, the surface nonuniformity of the particles was lower compared to Examples 1 to 4, which means that the introduction of the prepolymerization initiator was If it is too fast, the dispersion and activation time of the prepolymerization initiator is long, so that the initial particle appearance can be quickly and smoothly formed, and as a result, it is a result indicating that the nonuniformity of the particle surface cannot be controlled beyond a certain range.
[158]
In addition, Comparative Examples 1, 3 to 4, 7 and 8 also significantly reduced the porosity of the particles by about 4% to 8% compared to Examples 1 to 4. In the case of the manufacturing method of the present invention, it was confirmed that pores in the particles can be developed, and thus a vinyl chloride-based polymer having excellent pore characteristics can be prepared.
[159]
On the other hand, in Comparative Examples 9 and 10, the pre-polymerization was performed in the same manner as in Comparative Example 1 in order to confirm the change in the particle non-uniformity according to the conditions during post-polymerization. In the case of Comparative Example 9, the post polymerization initiator was added at the time of -2.5 K/G than the post polymerization, but the particle non-uniformity was not controlled. Rose. Through this, it was confirmed that the surface non-uniformity of the final polymer particles can be controlled by controlling the pre-polymerization pressure and the time of introduction of the pre-polymerization initiator during pre-polymerization. Rather, it was confirmed that it can act as an obstacle to the production of the desired polymer.
[160]
[161]
Experimental Example 2
[162]
The blendability, plasticizer absorption rate, protrusion property, and gelation rate of the vinyl chloride-based polymers of Examples and Comparative Examples were measured. The results are shown in Table 2 below.
[163]
On the other hand, in Comparative Example 2 and Comparative Example 5, the polymer was not prepared, and thus the physical properties were not measured.
[164]
(1) Blendability
[165]
100 g of each vinyl chloride polymer of Examples and Comparative Examples, 6 g of Ca-Zn thermal stabilizer, 7 g of acrylic impact modifier, 4 g of fat sugar (titanium dioxide), and 30 g of calcium carbonate were added to the Brabender Planetary Mixer, and then at 120° C. 12 Each powder was obtained by mixing for a period of time, and the non-passed residual amount was measured by passing it through a 35 mesh bar, and the ratio (weight%) of the residual amount to 100% by weight of the total powder was expressed as a blending property value. At this time, the lower the ratio of the remaining amount, the better the blending properties.
[166]
[167]
(2) gelation rate
[168]
50 g of the mixed powder obtained by mixing 100 parts by weight of each vinyl chloride polymer of Examples and Comparative Examples, 3 parts by weight of Ca-Zn thermal stabilizer, and 2 parts by weight of epoxidized soybean oil was added to a Brabender Planetary Mixer and then melted at 165° C. at 30 rpm. The resulting mechanical load was recorded and expressed as the gelation rate. At this time, the lower the gelation rate, the better the processability.
[169]
[170]
(3) Plasticizer absorption rate (CPA, wt%)
[171]
According to ASTM D3367-98, each vinyl chloride polymer of Examples and Comparative Examples was mixed with DOP (dioctyl phthalate), and the plasticizer absorption rate was measured by calculating by Equation 4 below.
[172]
[Equation 4]
[173]
Plasticizer water absorption (% by weight) = [(BA)/A]X100
[174]
In Equation 4, A is the weight of the vinyl chloride polymer, and B is the weight of the vinyl chloride polymer absorbed by the plasticizer after mixing with the plasticizer.
[175]
[176]
(4) protrusion characteristics
[177]
100 parts by weight of each vinyl chloride polymer of Examples and Comparative Examples, 45 parts by weight of DOP, 0.1 parts by weight of barium stearate, 0.2 parts by weight of tin stabilizer, 0.1 parts by weight of carbon black using a 6 inch roll at 145° C. for 4 minutes and kneading After that, a sheet having a thickness of 0.3 mm was made, and white transparent particles in 400 cm 2 of the sheet were counted by visual observation , and this was expressed as a protrusion characteristic. The smaller the number of white transparent particles, the better the protrusion characteristics, and as a result, the better the surface characteristics.
[178]
[Table 2]
[179]
As can be seen from Table 2, the vinyl chloride polymers of Examples 1 to 4 according to an embodiment of the present invention have more than twice the blendability of the vinyl chloride polymer of the comparative example, while the gelation rate is reduced by more than half, and the plasticizer Absorption rate was greatly increased and protrusions were greatly decreased. Through this, in the case of the vinyl chloride-based polymer prepared by the production method in which the pressure conditions of the prepolymerization step and the time point of the prepolymerization initiator are adjusted according to the present invention, the gelation rate is reduced and the plasticizer absorption rate is reduced by controlling the particle non-uniformity and porosity. It can be increased, and it has been confirmed that the blending properties are excellent and thus can exhibit greatly improved processability.
Claims
[Claim 1]
A vinyl chloride-based polymer having a particle non-uniformity of 10 or more defined by Equation 1 below: [Equation 1] In Equation 1, X i is a standard deviation of the i-th particle, and is a value defined by Equation 2 below, equation (2) in the equation (2), a n is i and the correction value of the n th measuring the diameter of the first particles, where the correction value is a value defined by equation (3), [equation 3] the equation In 3, D n is the n-th measured diameter of the i-th particle , D 0 is the longest diameter in the i-th particle, and n is an integer from 1 to 50.
[Claim 2]
The vinyl chloride-based polymer according to claim 1, wherein the vinyl chloride-based polymer has a particle non-uniformity of 11 or more and 16 or less.
[Claim 3]
The vinyl chloride-based polymer of claim 1, wherein the vinyl chloride-based polymer is a block polymer.
[Claim 4]
The vinyl chloride-based polymer of claim 1, wherein the vinyl chloride-based polymer has a porosity of 59% or more.
[Claim 5]
Adding a prepolymerization initiator to the first vinyl chloride-based monomer and prepolymerizing at a pressure of 8.0 K/G to 8.7 K/G to form particle nuclei; And post-polymerizing a second vinyl chloride-based monomer and a post polymerization initiator in the presence of the particle nuclei, wherein the pre-polymerization initiator is added at a low pressure of 1.3 K/G to 3.5 K/G compared to the pressure during pre-polymerization. The method for producing a vinyl chloride-based polymer of claim 1 having a particle non-uniformity of 10 or more defined by Equation 1 below: [Equation 1] In Equation 1, X i is the standard deviation of the i-th particle, Is a value defined by Equation 2, [Equation 2] In Equation 2, A n is a correction value of the n-th measurement diameter of the i-th particle, wherein the correction value is a value defined by Equation 3 below. , [Equation 3] In Equation 3, D n is the n-th measured diameter of the i-th particle , D 0 is the longest diameter in the i-th particle, and n is an integer of 1 to 50.
[Claim 6]
The method of claim 5, wherein the pre-polymerization initiator is added at a pressure of 1.5 K/G to 3.0 K/G lower than the pressure during pre-polymerization.
[Claim 7]
The method of claim 5, wherein the prepolymerization initiator is added in an amount of 0.01 parts by weight to 1 part by weight based on 100 parts by weight of the first vinyl chloride-based monomer.
[Claim 8]
The method of claim 5, wherein the prepolymerization is performed up to a polymerization conversion rate of 10% to 15%.
[Claim 9]
The method of claim 5, wherein the post-polymerization is performed at a pressure of 6 K/G to 13 K/G.
[Claim 10]
The method of claim 5, wherein the post polymerization initiator is used in an amount of 0.05 parts by weight to 2 parts by weight based on 100 parts by weight of the second vinyl chloride-based monomer.
[Claim 11]
The method according to claim 5, wherein the pre-polymerization initiator and the post-polymerization initiator are di-2-ethylhexyl peroxydicarbonate, t-butylperoxy neodecanoate, t-butylperoxy ester, cumyl peroxy ester, cumyl peroxy, respectively. Neodecanoate, 1,1,3,3-tetramethyl butyl peroxy neodecanoate, t-hexyl peroxy neodecanoate, t-hexyl peroxy pivalate, t-butyl peroxy pivalate, di In -sec-butyl peroxy dicarbonate, di-2-ethoxyethyl peroxy dicarbonate, isobutyryl peroxide, 3,5,5-trimethylhexanoyl peroxide, lauryl peroxide and octylperoxy dicarbonate A method for producing a vinyl chloride-based polymer that is at least one selected.