Polyolefin polymer, and system and method for polyolefin polymerization

Abstract

The present invention relates to a polyolefin polymer, and a polymerization system and polymerization method for preparing same, the polyolefin polymer comprising: a core portion; and a shell portion, wherein the core portion has a density of 0.857 g / cm3 to 0.910 g / cm3, the shell portion has a density of 0.890 g / cm3 to 0.940 g / cm3, and the density of the shell portion is higher than the density of the core portion.

Description

Polyolefin polymer, polymerization system and polymerization method of polyolefin

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0122347, filed September 14, 2023, and the benefit of priority from Korean Patent Application No. 10-2024-0003448, filed January 9, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a polyolefin polymer, a polymerization system for polyolefin, and a polymerization method.

[0005] Linear low-density polyethylene (LLDPE) is widely known to be produced through a gas phase process using a fluidized bed reactor, and is specifically manufactured by copolymerizing ethylene monomer and comonomer in the presence of a catalyst.

[0006] Here, when manufacturing polymers such as linear low-density polyethylene, large comonomers with four or more carbon atoms relative to the ethylene monomer are used. Because comonomers have low vapor pressures, they condense in the polymerization reactor and are absorbed into the polymer, causing the polymer to swell. Polymers containing large amounts of comonomer have low crystallinity and melting points, resulting in sticky, wet resins within the polymerization reactor. Such sticky polymers hinder fluidization in the reactor due to their sticky nature, negatively impacting the continuous operation of gas-phase polymerization reactors.

[0007] U.S. Patent Publication No. 4,994,534 describes a process for producing sticky polymers, such as ethylene / propylene rubber, by adding silica or clay during polymerization. Adding these materials to a reactor not only renders the polymer unusable for various applications, but can also cause contamination in heat exchangers, compressors, and other reactor systems.

[0008] Similarly, U.S. Patent Publication No. 4,970,279 and International Patent Publication No. WO 88 / 02379 describe methods for adding pulverized inorganic materials such as silica or alumina to a reactor. U.S. Patent Publication Nos. 5,100,979 and 5,106,926 describe processes for producing ethylene / 1-octene copolymers using certain titanium-based catalyst systems or certain vanadium-based catalyst systems that are not commercially available. U.S. Patent Publication No. 5,017,665 describes a process for producing ethylene / 1-butene / 1-4, hexadiene in the presence of a metallocene / aluminoxane catalyst system to produce polymers having very low molecular weight and low density. U.S. Patent Publication No. 5,712,353 describes a process for producing relatively high molecular weight and low density elastomers using a metallocene catalyst. This method produced elastomers with high molecular weight and low density at temperatures above 50°C, but there was a problem that there was a high possibility of process problems that made continuous operation difficult when produced at high temperatures due to the low melting point and sticky nature of the elastomers.

[0009] Furthermore, conventionally, a jacket was installed outside the reactor to remove internal heat, and heat was removed through heat exchange with cooling water supplied to the jacket. However, sufficient removal of reaction heat required a large area for heat exchange, which inevitably resulted in an excessively long external jacket.

[0010] [Prior Art Literature]

[0011] [Patent Document]

[0012] (Patent Document 1) 1. U.S. Patent Publication No. 4,994,534

[0013] (Patent Document 2) 2. U.S. Patent Publication No. 4,970,279

[0014] (Patent Document 3) 3. International Patent Publication No. WO 88 / 02379

[0015] (Patent Document 4) 4. U.S. Patent Publication No. 5,100,979

[0016] (Patent Document 5) 5. U.S. Patent Publication No. 5,106,926

[0017] (Patent Document 6) 6. U.S. Patent Publication No. 5,017,665

[0018] (Patent Document 7) 7. U.S. Patent Publication No. 5,712,353

[0019] The present invention provides a low-density polyolefin polymer including a core portion and a shell portion and having a density distribution such that the density of the shell portion is higher than the density of the core portion, and a polymerization system and a polymerization method thereof, thereby preventing the problem of reduced process stability due to difficulty in continuous operation due to stickiness when the surface of the polymer has a low density.

[0020] In addition, the present invention aims to solve the problem of the jacket length becoming excessively long, which is a disadvantage when using an external jacket, by providing a slurry polymerization reactor including a heat exchanger.

[0021] The present invention provides a polymerization system for polyolefin, comprising at least one slurry polymerization reactor for slurry polymerizing a feed stream supplied in the presence of a catalyst to produce a slurry reaction product comprising a prepolymer, wherein the feed stream comprises a monomer and a comonomer, and the slurry polymerization reactor comprises a loop comprising at least one reactor; at least one polymer discharge port; at least one monomer inlet port; at least one heat exchanger; and at least one circulation pump.

[0022] A shell portion can be formed through the above slurry polymerization reactor.

[0023] The above heat exchanger may be of shell and tube type.

[0024] In addition, the heat exchanger has a cooling water flow rate of 1 m / s or more, preferably 3 m / s or more, and a heat transfer efficiency of 0.3 Mcal / m 2 ×hr×K or more, preferably 0.6Mcal / m 2 It can be more than ×hr×K.

[0025] The polymerization system may additionally include one or more vapor phase polymerization reactors that receive the slurry reaction product, or the slurry reaction product and a feed stream, and subject them to vapor phase polymerization to produce a vapor phase reaction product comprising a final polymer.

[0026] A core portion can be formed through the above-mentioned gas phase polymerization reactor.

[0027] The above final polymer has two or more density distributions including a core portion and a shell portion having a higher density than the core portion, and the operating temperature of the slurry polymerization reactor is 20° C. to 70° C., and provides a polymerization system of polyolefin higher than the operating temperature of the gas phase polymerization reactor.

[0028] The density of the core part is 0.857 g / cm 3 0.910 g / cm 3 And the density of the shell part is 0.890 g / cm 3 0.940 g / cm 3 , and the density of the shell portion may be higher than the density of the core portion.

[0029] The final polymer may have one or more of the following properties (a) to (h):

[0030] (a) Melt flow index (MIE (2.16 kg load, 190°C)) of 0.1 g / 10 min to 5.0 g / 10 min;

[0031] (b) 0.870 g / cm 3 0.900 g / cm 3 density of

[0032] (c) Two or more melting temperatures (T m )

[0033] (d) First melting temperature (T m1 ) and the second melting temperature (T m2 ), and the difference between the first melting temperature and the second melting temperature is 30 ℃ to 70 ℃.

[0034] (e) First melting temperature (T m1 ) and the second melting temperature (T m2 ), the first melting temperature is 45°C to 85°C, and the second melting temperature is 80°C to 125°C.

[0035] (f) Two or more crystallization temperatures (T c )

[0036] (g) First crystallization temperature (T c1 ) and the second crystallization temperature (T c2 ), the first crystallization temperature is 40 ℃ to 100 ℃, and the second crystallization temperature is 70 ℃ to 110 ℃.

[0037] (h) In a temperature rising elution fractionation (TREF) chromatogram, two or more peaks are shown at a temperature of 35°C or higher, and the percentage value of the graph area above 60°C divided by the total graph area is 5% or more.

[0038] The above polyolefin polymerization system may include a first slurry polymerization reactor that subjected a feed stream supplied in the presence of a catalyst to a slurry polymerization reaction to produce a slurry reaction product including a prepolymer; and a first gas phase polymerization reactor that received the slurry reaction product, or the slurry reaction product and the feed stream, and subjected them to a gas phase polymerization reaction to produce a gas phase reaction product including a final polymer.

[0039] The above-described polyolefin polymerization system may include a first slurry polymerization reactor that slurry polymerizes a feed stream supplied in the presence of a catalyst to produce a first slurry reaction product including a prepolymer; a second slurry polymerization reactor that receives the first slurry reaction product from the first slurry polymerization reactor, or the first slurry reaction product and a feed stream, and subjectes the slurry polymerization reaction to produce a second slurry reaction product including a prepolymer; a first gas phase polymerization reactor that receives the second slurry reaction product from the second slurry polymerization reactor, or the second slurry reaction product and a feed stream, and subjectes the gas phase polymerization reaction to produce a first gas phase reaction product including a final polymer; and a second gas phase polymerization reactor that receives the first gas phase reaction product or the first gas phase reaction product and a feed stream from the first gas phase polymerization reactor, and subjectes the first gas phase reaction product to a gas phase polymerization reaction to produce a second gas phase reaction product including a final polymer.

[0040] The above catalyst may be a metallocene single catalyst.

[0041] The above monomer may be ethylene.

[0042] The above monomer may be at least one selected from the group consisting of 1-butene, 1-hexene, 1-pentene, 4-methyl-1-pentene, and 1-octene.

[0043] The operating temperature of the above slurry polymerization reactor may be 40°C to 60°C, and the operating temperature of the above gas phase polymerization reactor may be 30°C to 50°C.

[0044] The above gas phase polymerization reactor has an MIT measured according to ASTM 3417-83. 15 (15 wt% melting initiation temperature) can be operated at a temperature below.

[0045] The above second gas phase polymerization reactor is operated in a high sorption mode, and in the high sorption mode, the sorbent can be used in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the total circulating gas stream.

[0046] The present invention utilizes one or more slurry polymerization reactors and one or more gas phase polymerization reactors, and introduces a heat exchanger into the slurry polymerization reactors to achieve efficient heat removal within the reactors, thereby increasing the polymer production amount. In addition, by controlling the operating conditions of each of the slurry polymerization reactors and the gas phase polymerization reactors, process stability can be secured in producing a polyolefin polymer, and the polyolefin polymer produced thereby can have a structure including a core portion and a shell portion, and having a density distribution such that the density of the shell portion is higher than the density of the core portion.

[0047] FIG. 1 is a diagram showing the structure of a slurry polymerization reactor according to one embodiment of the present invention.

[0048] FIG. 2a is a diagram showing the structure of a first slurry polymerization reactor and a first gas phase polymerization reactor according to one embodiment of the present invention.

[0049] FIG. 2b is a diagram showing the structure of the first and second slurry polymerization reactors and the first gas phase polymerization reactor according to one embodiment of the present invention.

[0050] FIG. 2c is a diagram showing the structure of a first slurry polymerization reactor and first and second gas phase polymerization reactors according to one embodiment of the present invention.

[0051] FIG. 2d is a diagram showing the structures of the first and second slurry polymerization reactors and the first and second gas phase polymerization reactors according to one embodiment of the present invention.

[0052] FIG. 3 is a diagram showing the structure of a shell-and-tube heat exchanger according to one embodiment of the present invention.

[0053] Figure 4a is a cross-sectional SEM image of the prepolymer manufactured in Example 2.

[0054] Figure 4b is a cross-sectional SEM image of the final polymer manufactured in Example 2.

[0055] Figure 4c is an SEM image of the final polymer manufactured in Example 2 before and after xylene dissolution.

[0056] Figure 5 is a temperature rising elution fractionation (TREF) chromatogram showing the TREF value measured according to temperature for the final polymers manufactured in Example 5 and Comparative Example 3.

[0057] The terms or words used in the description and claims of the present invention should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best possible manner.

[0058] In the present invention, the term "stream" may refer to the flow of fluid within a process, and may also refer to the fluid itself flowing within a pipe. Specifically, the "stream" may refer to both the fluid itself flowing within a pipe connecting each device and the flow of the fluid. In addition, the fluid may refer to a gas or a liquid, and does not exclude the case where the fluid includes a solid component.

[0059] The following implementation examples are described in detail so that those skilled in the art can easily implement them. However, the implementation examples can be implemented in various different forms and are not limited to the implementation examples described herein.

[0060] A polyolefin polymer according to one embodiment includes a core portion and a shell portion, and the density of the core portion is 0.857 g / cm 3 0.910 g / cm 3 And the density of the shell part is 0.890 g / cm 3 0.940 g / cm 3 , and the density of the shell portion may be higher than the density of the core portion.

[0061] As described above, a polyolefin polymer having a core-shell structure having a core portion and a shell portion surrounding the core portion, wherein the core portion and the shell portion have the density ranges as described above, and the polyolefin polymer has a relatively high density on the shell portion, i.e., on the surface of the polymer, so that when a low-density polymer is manufactured, when the surface density of the polymer is low in the polymerization step, fluidization is prevented in a gas phase polymerization reactor due to stickiness, and polymers are prevented from clumping together or peripheral devices such as pipes or heat exchangers are easily clogged, so that the polymer can be manufactured through stable continuous operation.

[0062] In one embodiment, the polyolefin polymer may have one or more of the following properties (a) to (h). For example, the polyolefin polymer may have two or more or all of the following properties (a) to (h).

[0063] (a) Melt flow index (MIE (2.16 kg load, 190°C)) of 0.1 g / 10 min to 5.0 g / 10 min;

[0064] (b) 0.870 g / cm 3 0.900 g / cm 3 density of

[0065] (c) Two or more melting temperatures (T m )

[0066] (d) First melting temperature (T m1 ) and the second melting temperature (T m2 ), and the difference between the first melting temperature and the second melting temperature is 30 ℃ to 70 ℃.

[0067] (e) First melting temperature (T m1 ) and the second melting temperature (T m2 ), the first melting temperature is 45°C to 85°C, and the second melting temperature is 80°C to 125°C.

[0068] (f) Two or more crystallization temperatures (T c )

[0069] (g) First crystallization temperature (T c1 ) and the second crystallization temperature (T c2 ), the first crystallization temperature is 40 ℃ to 100 ℃, and the second crystallization temperature is 70 ℃ to 110 ℃.

[0070] (h) In a temperature rising elution fractionation (TREF) chromatogram, two or more peaks are shown at a temperature of 35°C or higher, and the percentage value of the graph area above 60°C divided by the total graph area is 5% or more.

[0071] In the above (a), the melt flow index (MIE (2.16 kg load, 190°C)) may refer to a melt flow index value of a polyolefin polymer measured according to ASTM D1238 under conditions of 190°C and 2.16 kg load. The melt flow index of the polyolefin polymer may be, for example, 0.1 g / 10 min to 5.0 g / 10 min, 0.5 g / 10 min to 4.0 g / 10 min, or 0.6 g / 10 min to 3.2 g / 10 min. By having a melt flow index within the above range, process stability and processability may be excellent.

[0072] In the above (b), the density may refer to the density of the polyolefin polymer measured by the density gradient method according to ASTM D1505. The density of the polyolefin polymer may be, for example, 0.870 g / cm 3 0.900 g / cm 3 , preferably 0.885 g / cm 3 0.890 g / cm 3 It is possible to provide a low-density polyolefin polymer having a density within the above range.

[0073] In the above (c), the melting temperature (T m ) may refer to the melting temperature of a polyolefin polymer measured in accordance with ASTM 3417-83. The polyolefin polymer may have two or more melting temperature distributions. For example, the polyolefin polymer may have two to four, two to three, or two melting temperature distributions.

[0074] In the above (d), the polyolefin polymer has a first melting temperature (T m1 ) and the second melting temperature (T m2 ), the difference between the first melting temperature and the second melting temperature may be 30°C to 70°C, 31°C to 68°C, or 33°C to 38°C.

[0075] In the above (e), the first melting temperature may be 45°C to 85°C, 50°C to 85°C, or 60°C to 70°C, and the second melting temperature may be 80°C to 125°C, 90°C to 120°C, or 95°C to 110°C.

[0076] In the above (f), the crystallization temperature (T c ) may refer to the crystallization temperature of the polyolefin polymer measured in accordance with ASTM 3417-83, similar to the melting temperature above. The polyolefin polymer may have two or more crystallization temperature distributions. For example, the polyolefin polymer may have two to four, two to three, or two crystallization temperature distributions.

[0077] In the above (g), the polyolefin polymer has a first crystallization temperature (T c1 ) and the second crystallization temperature (T c2 ) may have. Here, the first crystallization temperature may be 40° C. to 100° C., 43° C. to 97° C., or 44° C. to 50° C. In addition, the second crystallization temperature may be 70° C. to 110° C., 72° C. to 109° C., or 74° C. to 87° C.

[0078] In the above (h), the temperature rising elution fractionation (TREF) chromatogram may be obtained by analyzing the polyolefin polymer using a cross-fractionation chromatography (CFC, PolymerChar CFC-2) equipment. The temperature rising elution fractionation (TREF) chromatogram of the polyolefin polymer may show two or more, two to five, or two peaks at a temperature of 35°C or higher. In the temperature rising elution fractionation (TREF) chromatogram, the percentage value obtained by dividing the graph area at 60°C or higher by the total graph area may be 5% or more, 5% to 55%, or 5% to 50%. As shown above, it can be confirmed that the polyolefin polymer has a density gradient by showing two or more peaks in the temperature rising elution fractionation (TREF) chromatogram, and the percentage value of the graph area above 60°C divided by the total graph area is 5% or more, confirming that a relatively high-density shell portion formed through a slurry polymerization reaction and eluted at a high temperature is well formed.

[0079] In one embodiment, the shell portion may be formed through a slurry polymerization reaction in the polyolefin polymerization system or polymerization method described below. Specifically, in the polyolefin polymer, a shell portion having a hollow structure and relatively high density may be formed first.

[0080] The density of the above shell part is, for example, 0.890 g / cm 3 0.940 g / cm 3 , 0.895 g / cm 3 0.930 g / cm 3 or 0.900 g / cm 3 0.922 g / cm 3 It could be.

[0081] The melt flow index (MIE (2.16 kg load, 190°C)) of the above shell portion may be, for example, 0.01 g / 10 min to 5.0 g / 10 min, 0.05 g / 10 min to 3.5 g / 10 min, or 0.05 g / 10 min to 2.0 g / 10 min.

[0082] The melting temperature of the shell portion may be, for example, 80°C to 125°C, 90°C to 120°C or 95°C to 110°C.

[0083] The temperature rising elution fractionation (TREF) chromatogram of the above shell portion may have one peak at a temperature of 60°C or higher.

[0084] In one embodiment, the core portion may be formed through a gas phase polymerization reaction in the polyolefin polymerization system or polymerization method described below. Specifically, in the polyolefin polymer, the core portion may be formed in a structure in which the hollow portion of the shell portion formed through the slurry polymerization reaction is filled with a relatively low density product.

[0085] The density of the core portion is, for example, 0.857 g / cm 3 0.910 g / cm 3 , 0.857 g / cm 3 0.900 g / cm 3 or 0.857 g / cm 3 0.898 g / cm 3 It could be.

[0086] The melting temperature of the core portion may be, for example, 45°C to 85°C, 50°C to 85°C, or 60°C to 70°C.

[0087] The weight ratio of the core portion and the shell portion may be 40:60 to 90:10, 50:50 to 80:20, or 50:50 to 70:30. By forming the core portion and the shell portion with a weight ratio within the above range, a low-density polyolefin polymer can be provided, and at the same time, the relatively low-density core portion can be prevented from leaking out to the polymer surface, thereby further improving process stability.

[0088] As described above, a polyolefin polymer formed of a core portion and a shell portion having different physical properties not only has a low-density characteristic, but also has a hollow shell portion having a relatively high density forming a surface, and a core portion having a relatively low density filling the hollow interior of the shell portion, so that when the density of the polymer surface is low, the problem of process stability being hindered due to sticky and wet characteristics can be prevented.

[0089] The melt flow index (MIE (2.16 kg load, 190°C)) of the polyolefin polymer may be, for example, 0.1 g / 10 min to 5.0 g / 10 min, 0.5 g / 10 min to 4 g / 10 min, or 0.6 g / 10 min to 3.2 g / 10 min.

[0090] A polymerization system for polyolefin according to one embodiment comprises one or more slurry polymerization reactors for slurry polymerizing a feed stream supplied in the presence of a catalyst to produce a slurry reaction product comprising a prepolymer, wherein the feed stream comprises a monomer and a comonomer, and the slurry polymerization reactor may comprise a loop comprising one or more reactors; one or more polymer discharge ports; one or more monomer inlets; one or more heat exchangers; and one or more circulation pumps.

[0091] A shell portion can be formed through the above slurry polymerization reactor.

[0092] The heat exchanger can effectively remove the polymerization heat from the reactor by cooling the slurry and returning the cooled slurry to the reactor. Each slurry polymerization reactor system may include one or more of the heat exchangers, for example, two or three.

[0093] The above heat exchanger may be selected from a double-pipe, shell-and-tube, plate, plate, or shell-and-spiral heat exchanger, but a shell-and-tube heat exchanger is preferred. Despite its compact configuration, the shell-and-tube heat exchanger has a large heat transfer area and satisfies sufficient heat removal capacity for use in confined spaces on site.

[0094] Specifically, an example of the shell-and-tube heat exchanger is illustrated in Fig. 3. As shown in Fig. 3, the shell-and-tube heat exchanger is in a vertically elongated shape, and a head, a tube sheet, and a nozzle are formed at the upper and lower ends, respectively, and a tube, a shell, and a baffle are formed in the middle.

[0095] The head forms the area where the heat medium enters or exits the heat exchanger. The tube sheet secures the tubes and maintains a seal between the tubes and the shell, playing a crucial role in maintaining the structural stability of the heat exchanger. The nozzle provides a passage for the cooling water to enter and exit the heat exchanger and controls the fluid flow.

[0096] The above heat exchanger may be composed of a plurality of tubes, through which cooling water passes, effectively transferring heat from within the reactor to the outside. The plurality of tubes may be arranged parallel to one another and configured in a dense configuration to maximize the heat transfer surface area.

[0097] The shell is an outer structure that surrounds a number of tubes and acts as a protective film for the heat exchanger. Furthermore, a space is provided within the shell through which cooling water can circulate. Through this space, heat from within the reactor is released to the outside.

[0098] Multiple baffles are installed within the shell, spaced apart and arranged in a zigzag pattern. This arrangement of baffles intermittently blocks the flow of coolant, increasing the contact time between the tubes and the coolant, thereby enhancing heat exchange efficiency.

[0099] The above heat exchanger has a cooling water flow rate of 1 m / s or more, preferably 3 m / s or more, and a heat transfer efficiency of 0.3 Mcal / m 2 ×hr×K or more, preferably 0.6Mcal / m 2 It can be more than ×hr×K, where hr represents time and K represents absolute temperature.

[0100] The slurry polymerization reactor of the present invention comprises at least one circulation pump for recovering the reactor contents and circulating the reactor contents through a heat exchanger. The circulation pump may be preferably positioned upstream of the heat exchanger, i.e., between the outlet of the polymerization reactor and the heat exchanger, but is not limited thereto.

[0101] The polymerization system may additionally include one or more vapor phase polymerization reactors that receive the slurry reaction product, or the slurry reaction product and a feed stream, and subject them to vapor phase polymerization to produce a vapor phase reaction product comprising a final polymer.

[0102] A core portion can be formed through the above-mentioned gas phase polymerization reactor.

[0103] The final polymer has two or more density distributions, including a core portion and a shell portion having a higher density than the core portion, and the operating temperature of the slurry polymerization reactor is 20° C. to 70° C., and may be higher than the operating temperature of the gas phase polymerization reactor.

[0104] The above polyolefin polymerization system may be a system for producing a final polymer, i.e., the above-described polyolefin polymer.

[0105] In one embodiment, each of the one or more slurry polymerization reactors and the one or more gas phase polymerization reactors may be connected in series.

[0106] In one embodiment, the catalyst may use a metallocene single catalyst. The metallocene may be represented by the chemical formula LnMQp, where M is a metal of Group IIIB, Group IVB, Group VB, or Group VIB; Q is a hydrocarbyl group or halogen having 1 to 20 carbon atoms; p is the valence of M -2, and L is a ligand bonded to the metal M.

[0107] These metallocene catalysts are known as catalyst systems that produce polyolefins with superior physical properties due to their high activity and high copolymerization reactivity compared to existing Ziegler-Natta catalysts. The metallocene catalysts can be used as homogeneous catalysts by being supported on a suitable support. For example, the support may be silicon and / or aluminum oxide, and as a specific example, it may be silica having OH groups or other functional groups containing active hydrogen atoms, and may be in the form of porous spherical particles.

[0108] The metallocene catalyst may be supported on a support together with a cocatalyst, and the cocatalyst may be an alkylaluminoxane. The alkylaluminoxane includes a linear and / or cyclic alkylaluminoxane oligomer, and when the alkylaluminoxane is a linear alkylaluminoxane oligomer, the chemical formula is R-(Al(R)-O). n -AlR2 is indicated, and in the case of cyclic alkylaluminoxane oligomer, the chemical formula is (-Al(R)-O-) m , where R is a C1~C8 alkyl group, preferably methyl, n is 1~40, preferably 10~20, and m is 3~40, preferably 3~20. The alkylaluminoxane is a mixture of oligomers having a very wide molecular weight distribution, and typically the average molecular weight may be 800 to 1200.

[0109] In one embodiment, the feed stream may comprise monomers and comonomers.

[0110] The above monomer may be ethylene.

[0111] The above comonomer may be at least one selected from the group consisting of 1-butene, 1-hexene, 1-pentene, 4-methyl-1-pentene, and 1-octene. As a specific example, the comonomer may be at least one of 1-butene and 1-hexene.

[0112] The above feed stream may further comprise a diluent. The diluent may be at least one of an inert gas and an alkane. Here, the inert gas may include nitrogen, helium, neon, etc., and the alkane may include butane, propane, isobutane, isopentane, hexane, and isomers thereof. The method may further include a step of contacting a catalyst with monomers and comonomers in a slurry polymerization reactor and a gas phase polymerization reactor using the diluent to produce a polyolefin polymer.

[0113] In the presence of the above catalyst, a feed stream containing ethylene and a comonomer can be polymerized using a system in which one or more slurry polymerization reactors and one or more gas phase polymerization reactors are sequentially arranged to produce a polyolefin polymer, specifically a polyolefin elastomer, and more specifically a low density polyethylene.

[0114] In one embodiment, the operating temperature of the slurry polymerization reactor may be 20° C. to 70° C. or 40° C. to 60° C. In addition, the operating temperature of the gas phase polymerization reactor may be lower than the operating temperature of the slurry polymerization reactor, for example, 30° C. to 50° C. or 35° C. to 48° C. By lowering the operating temperature of each reactor to produce the final polymer as described above, the portion where the sticky and wet resin interferes with the fluidization of the reactor can be minimized, thereby further improving process stability.

[0115] In one embodiment, the operating pressure of the slurry polymerization reactor may be 5 K / G to 30 K / G, to 10 K / G or 25 K / G or 20 K / G to 25 K / G. In addition, the operating pressure of the gas phase polymerization reactor may be controlled to be lower than the operating pressure of the slurry polymerization reactor, for example, the pressure of the gas phase polymerization reactor may be operated at 10 K / G to 20 K / G or 10 K / G to 15 K / G depending on the temperature of the slurry reactor. In this way, by lowering the operating pressure of each reactor to manufacture the final polymer as described above, the sticky and wet resin that interferes with the fluidization of the reactor can be minimized, thereby further improving the process stability. Here, the pressure unit K / G is kg / cm 2 It means.

[0116] In one embodiment, through multi-stage polymerization of one or more slurry polymerization reactors and one or more gas phase polymerization reactors, a prepolymer having a relatively high density and forming a hollow shell structure was manufactured in the slurry polymerization reaction, and in the gas phase polymerization reactor, a polyolefin polymer, i.e., a polyolefin elastomer (POE), was filled into the hollow interior of the prepolymer particles to manufacture a final polymer, wherein the final polymer can have the properties of a polyolefin elastomer.

[0117] In one embodiment, the molar ratio of ethylene and comonomer alpha-olefin in each reactor can be controlled from 0.01 to 0.3 depending on the type of comonomer. For example, in the slurry polymerization reactor, the molar ratio of the comonomer to the total amount of the monomers and comonomers can be from 0.01 to 0.3, from 0.05 to 0.3, or from 0.07 to 0.27, and in the gas phase polymerization reactor, the molar ratio of the comonomer to the total amount of the monomers and comonomers can be from 0.01 to 0.2, or from 0.05 to 0.18. By varying the comonomer ratio in each reactor, a polymer having two or more properties such as dissolution temperatures or two or more crystallization temperatures can be produced, and a polymer having a high dissolution temperature and a low glass transition temperature (Tg) can exhibit great advantages in both processing and properties.

[0118] The prepolymer produced in the above slurry polymerization reactor may account for 10 wt% to 60 wt% of the total amount of the final polymer produced. For example, the prepolymer may account for 20 wt% to 50 wt% or 30 wt% to 50 wt% of the total amount of the final polymer. By adjusting the weight ratio of the prepolymer to the total amount of the final polymer within the above range, the overall density is increased, so that a relatively high-density shell portion is firmly formed without deteriorating the physical properties of the final polymer, and the polymer produced in the gas phase polymerization reactor is hardly present on the outside, so that the process stability can be improved.

[0119] In one embodiment, the gas phase polymerization reactor has an MIT measured according to ASTM 3417-83. 15 (15 wt% melting initiation temperature) can be operated at a temperature below. Specifically, the MIT 15 The temperature below is to set the process operation temperature while operating the temperature of each reactor low to ensure process stability, and the above MIT15 The temperature below was measured using a DSC device according to the ASTM 3417-83 method, and was measured based on the part where 15 wt% melt area percent appears in the 1st scan from 25 ℃ to 200 ℃ under the condition of 10 ℃ / min.

[0120] For example, in the above gas phase polymerization reactor, MIT 15 The temperature below may be 40°C to 80°C, 40°C to 70°C or 40°C to 65°C. The MIT 15 Controlling a gas phase polymerization reactor at the same temperature as the temperature can cause polymer agglomeration and reduce process stability. On the other hand, operating the reactor temperature too low to ensure process stability has the disadvantage of very low production volume. In addition, in the process of manufacturing polyolefin polymers with high comonomer content, a situation occurs where the comonomer ratio is locally high when production volume increases, which increases the adhesiveness of the polymer and creates a heterogeneous polymer, which can be a factor in process trouble. MIT within the above range 15 This problem can be prevented by controlling the temperature of the gas phase polymerization reactor.

[0121] In one embodiment, when the slurry polymerization reactor is placed before a gas phase polymerization reactor, not only can the metallocene catalyst be prevented from being directly exposed to the gas phase polymerization reactor conditions, but the slurry polymerization reaction can also increase the size of the polymer, which is helpful for process stability. In addition, when a low-density prepolymer is produced in a slurry polymerization reactor, the polymer having the properties of a polyolefin elastomer increases on the outside, and the polymer as a whole has a sticky characteristic, which can cause a problem of lowering process stability.

[0122] The final polymer according to one embodiment may be the polyolefin polymer described above. Specifically, the final polymer includes a core portion and a shell portion, and the density of the core portion is 0.857 g / cm. 3 0.910 g / cm 3 And the density of the shell part is 0.890 g / cm 3 0.940 g / cm 3 , and the density of the shell portion may be higher than the density of the core portion.

[0123] The final polymer may have one or more of the following properties (a) to (h). For example, the polyolefin polymer may have two or more or all of the following properties (a) to (h).

[0124] (a) Melt flow index (MIE (2.16 kg load, 190°C)) of 0.1 g / 10 min to 5.0 g / 10 min;

[0125] (b) 0.870 g / cm 3 0.900 g / cm 3 density of

[0126] (c) Two or more melting temperatures (T m )

[0127] (d) First melting temperature (T m1 ) and the second melting temperature (T m2 ), and the difference between the first melting temperature and the second melting temperature is 30 ℃ to 70 ℃.

[0128] (e) First melting temperature (T m1 ) and the second melting temperature (T m2 ), the first melting temperature is 45°C to 85°C, and the second melting temperature is 80°C to 125°C.

[0129] (f) Two or more crystallization temperatures (T c )

[0130] (g) First crystallization temperature (T c1 ) and the second crystallization temperature (Tc2 ), the first crystallization temperature is 40 ℃ to 100 ℃, and the second crystallization temperature is 70 ℃ to 110 ℃.

[0131] (h) In a temperature rising elution fractionation (TREF) chromatogram, two or more peaks are shown at a temperature of 35°C or higher, and the percentage value of the graph area above 60°C divided by the total graph area is 5% or more.

[0132] In one embodiment, the shell portion, i.e. the prepolymer prepared in the slurry polymerization reactor, has a density of, for example, 0.890 g / cm 3 0.940 g / cm 3 , 0.895 g / cm 3 0.930 g / cm 3 or 0.900 g / cm 3 0.922 g / cm 3 It could be.

[0133] The melt flow index (MIE (2.16 kg load, 190°C)) of the above shell portion may be, for example, 0.01 g / 10 min to 5.0 g / 10 min, 0.05 g / 10 min to 3.5 g / 10 min, or 0.05 g / 10 min to 2.0 g / 10 min.

[0134] The melting temperature of the shell portion may be, for example, 80°C to 125°C, 90°C to 120°C or 95°C to 110°C.

[0135] The temperature rising elution fractionation (TREF) chromatogram of the above shell portion may have one peak at a temperature of 60°C or higher.

[0136] In one embodiment, the density of the core formed inside the hollow interior of the prepolymer through the above-described gas phase polymerization reaction is, for example, 0.857 g / cm 3 0.910 g / cm 3 , 0.857 g / cm 3 0.900 g / cm 3or 0.857 g / cm 3 0.898 g / cm 3 It could be.

[0137] The melting temperature of the core portion may be, for example, 45°C to 85°C, 50°C to 85°C, or 60°C to 70°C.

[0138] The melt flow index (MIE (2.16 kg load, 190°C)) of the final polymer may be, for example, 0.1 g / 10 min to 5.0 g / 10 min, 0.5 g / 10 min to 4 g / 10 min, or 0.6 g / 10 min to 3.2 g / 10 min.

[0139] In the final polymer, the weight ratio of the core and shell portions may be 40:60 to 90:10, 50:50 to 80:20, or 50:50 to 70:30. By forming the core and shell portions at a weight ratio within the above range, a final polymer having the characteristics of a polyolefin elastomer with a low density while at the same time preventing process stability from being impaired due to sticky or wet properties that hinder fluidization can be provided.

[0140] As described above, the shell and core have different properties, so that two or more characteristics, such as melting temperature and crystallization temperature, appear in one polyolefin polymer.

[0141] As an example, the polymerization system for the polyolefin may include one slurry polymerization reactor and one gas phase polymerization reactor. In this case, the polymerization system for the polyolefin may include a first slurry polymerization reactor (100) that performs a slurry polymerization reaction on a feed stream supplied in the presence of a catalyst to produce a slurry reaction product including a prepolymer; and a first gas phase polymerization reactor (300) that receives the slurry reaction product, or the slurry reaction product and the feed stream, and performs a gas phase polymerization reaction on the slurry reaction product to produce a gas phase reaction product including a final polymer.

[0142] As another example, the polyolefin polymerization system may include one slurry polymerization reactor and two gas phase polymerization reactors. In this case, the polyolefin polymerization system may include a first slurry polymerization reactor (100) that subjected a feed stream supplied in the presence of a catalyst to a slurry polymerization reaction to produce a slurry reaction product including a prepolymer; a first gas phase polymerization reactor (300) that received the slurry reaction product, or the slurry reaction product and a feed stream from the first slurry polymerization reactor (100), subjected the slurry reaction product, or the slurry reaction product and a feed stream, to a gas phase polymerization reaction to produce a first gas phase reaction product including a final polymer; and a second gas phase polymerization reactor (400) that received the first gas phase reaction product, or the first gas phase reaction product and a feed stream from the first gas phase polymerization reactor (300), subjected the slurry polymerization product, or the first gas phase reaction product and a feed stream, to a gas phase polymerization reaction to produce a second gas phase reaction product including a final polymer.

[0143] As another example, the polyolefin polymerization system may include two slurry polymerization reactors and two gas phase polymerization reactors. In this case, the polyolefin polymerization system may include: a first slurry polymerization reactor (100) which performs a slurry polymerization reaction on a feed stream supplied in the presence of a catalyst to produce a first slurry reaction product including a prepolymer; a second slurry polymerization reactor (200) which receives the first slurry reaction product, or the first slurry reaction product and a feed stream from the first slurry polymerization reactor (100), and performs a slurry polymerization reaction on the first slurry reaction product to produce a second slurry reaction product including a prepolymer; a first gas phase polymerization reactor (300) which receives the second slurry reaction product, or the second slurry reaction product and a feed stream from the second slurry polymerization reactor (200), and performs a gas phase polymerization reaction on the second slurry reaction product to produce a first gas phase reaction product including a final polymer; And it may include a second gas phase polymerization reactor (400) that receives the first gas phase reaction product, or the first gas phase reaction product and a feed stream from the first gas phase polymerization reactor (300), and performs a gas phase polymerization reaction to produce a second gas phase reaction product including a final polymer.

[0144] In one embodiment, the first gas phase reaction product generated in the first gas phase polymerization reactor (300) may be separated from unreacted gas and polymer in a filter, the separated polymer may be supplied to the second gas phase polymerization reactor (400), and the unreacted gas may be refluxed to the first slurry polymerization reactor (100) and / or the second slurry polymerization reactor (200) through a purification tower.

[0145] Operating the above-described gas-phase polymerization reactor at too low a temperature has the disadvantage of significantly lowering production yields. Furthermore, during the production process of polyolefin polymers with high comonomer content, localized high comonomer ratios may occur as production increases. This can increase polymer viscosity, leading to the formation of heterogeneous polymers and potentially causing process problems. The present invention utilizes a high-sorption mode to reduce polymer viscosity under high comonomer concentration conditions.

[0146] As a specific example, the first gas phase polymerization reactor (300) may not be operated in a high sorption mode, and the second gas phase polymerization reactor (400) may be operated in a high sorption mode. The second gas phase polymerization reactor (400) may be operated under temperature and pressure conditions where the injected gas is condensed, while the gas discharged from the reactor is not condensed.

[0147] For reference, the polyolefin polymerization system may include a circulation line extending from the upper part of the gas phase polymerization reactor and connected to the lower part of the gas phase polymerization reactor to circulate a circulation gas stream, a compressor provided in the circulation line, and a heat exchanger provided at a later stage than the compressor based on the flow direction of the circulation gas stream in the circulation line, wherein in the high sorption mode, the sorbent may be used in an amount of 0.1 to 30 parts by weight, 2 to 20 parts by weight, or 3 to 15 parts by weight, based on 100 parts by weight of the total circulation gas stream.

[0148] The sorption agent used when the above second gas phase polymerization reactor (400) is operated in high sorption mode may include propane, isobutane, isopentane, hexane, etc.

[0149]

[0150] According to one embodiment, a method for polymerizing a polyolefin includes a slurry polymerization step of subjecting a feed composition containing a monomer and a comonomer to a slurry polymerization reaction at least once in the presence of a catalyst to produce a slurry reaction product containing a prepolymer; and a vapor phase polymerization step of subjecting the slurry reaction product obtained above, or the slurry reaction product and the feed composition to a vapor phase polymerization reaction at least once to produce a vapor phase reaction product containing a final polymer; wherein the reaction temperature of the slurry polymerization step is 20° C. to 70° C. and is performed at a temperature higher than the reaction temperature of the vapor phase polymerization step, and the final polymer may have two or more density distributions including a core portion and a shell portion having a higher density than the core portion.

[0151] The above-described method for polymerizing polyolefin may be a method for producing a final polymer, i.e., the above-described polyolefin polymer, using the above-described polyolefin polymerization system.

[0152] In one embodiment, the catalyst may use a metallocene single catalyst. The metallocene may be represented by the chemical formula LnMQp, where M is a metal of Group IIIB, Group IVB, Group VB, or Group VIB; Q is a hydrocarbyl group or halogen having 1 to 20 carbon atoms; p is the valence of M -2, and L is a ligand bonded to the metal M.

[0153] These metallocene catalysts are known as catalyst systems that produce polyolefins with superior physical properties due to their high activity and high copolymerization reactivity compared to existing Ziegler-Natta catalysts. The metallocene catalysts can be used as homogeneous catalysts by being supported on a suitable support. For example, the support may be silicon and / or aluminum oxide, and as a specific example, it may be silica having OH groups or other functional groups containing active hydrogen atoms, and may be in the form of porous spherical particles.

[0154] The metallocene catalyst may be supported on a support together with a cocatalyst, and the cocatalyst may be an alkylaluminoxane. The alkylaluminoxane includes a linear and / or cyclic alkylaluminoxane oligomer, and when the alkylaluminoxane is a linear alkylaluminoxane oligomer, the chemical formula is R-(Al(R)-O). n -AlR2 is indicated, and in the case of cyclic alkylaluminoxane oligomer, the chemical formula is (-Al(R)-O-) m , where R is a C1~C8 alkyl group, preferably methyl, n is 1~40, preferably 10~20, and m is 3~40, preferably 3~20. The alkylaluminoxane is a mixture of oligomers having a very wide molecular weight distribution, and typically the average molecular weight may be 800 to 1200.

[0155] In one embodiment, the feed stream may comprise monomers and comonomers.

[0156] The above monomer may be ethylene.

[0157] The above comonomer may be at least one selected from the group consisting of 1-butene, 1-hexene, 1-pentene, 4-methyl-1-pentene, and 1-octene. As a specific example, the comonomer may be at least one of 1-butene and 1-hexene.

[0158] The above feed stream may further comprise a diluent. The diluent may be at least one of an inert gas and an alkane. Here, the inert gas may include nitrogen, helium, neon, etc., and the alkane may include butane, propane, isobutane, isopentane, hexane, and isomers thereof. The method may further include a step of producing a polyolefin polymer by contacting monomers and comonomers using the diluent in a slurry polymerization reactor and a gas phase polymerization reactor.

[0159] In the presence of the above catalyst, a feed stream containing ethylene and a comonomer can be polymerized using a system in which one or more slurry polymerization reactors and one or more gas phase polymerization reactors are sequentially arranged to produce a polyolefin polymer, specifically a polyolefin elastomer, and more specifically a low density polyethylene.

[0160] In one embodiment, the temperature of the slurry polymerization reaction may be 20° C. to 70° C. or 40° C. to 60° C. In addition, the temperature of the gas phase polymerization reaction may be lower than the temperature of the slurry polymerization reaction, for example, 30° C. to 50° C. or 35° C. to 48° C. By lowering the operating temperature of each reaction in this way to produce the final polymer as described above, the portion where the sticky and wet resin interferes with the fluidization of the reactor can be minimized, thereby further improving process stability.

[0161] In one embodiment, the pressure of the slurry polymerization reaction may be 5 K / G to 30 K / G, to 10 K / G, or 25 K / G, or 20 K / G to 25 K / G. In addition, the pressure of the gas phase polymerization reaction may be controlled at a temperature lower than the operating pressure of the slurry polymerization reaction, and may be operated at, for example, 10 K / G to 20 K / G, or 10 K / G to 15 K / G, depending on the temperature. By lowering the pressure of each reactor in this way to manufacture the final polymer as described above, the portion where the sticky and wet resin interferes with the fluidization of the reactor can be minimized, thereby further improving the process stability.

[0162] In one embodiment, through multi-stage polymerization of one or more slurry polymerization reactions and one or more gas phase polymerization reactions, a prepolymer having a relatively high density and forming a hollow shell structure was prepared in the slurry polymerization reaction, and a final polymer was prepared by filling a polyolefin polymer, i.e., a polyolefin elastomer (POE), inside the hollow interior of the prepolymer particles in the gas phase polymerization reaction, wherein the final polymer can have the properties of a polyolefin elastomer.

[0163] In one embodiment, the molar ratio of ethylene and comonomer alpha-olefin in each reaction can be adjusted to 0.01 to 0.3 depending on the type of comonomer. For example, in the slurry polymerization reaction, the molar ratio of the comonomer to the total amount of the monomer and comonomer can be 0.01 to 0.3, 0.05 to 0.3, or 0.07 to 0.27, and in the gas phase polymerization reaction, the molar ratio of the comonomer to the total amount of the monomer and comonomer can be 0.01 to 0.2 or 0.05 to 0.18. By varying the comonomer ratio in each reaction, a polymer having two or more properties such as dissolution temperatures or two or more crystallization temperatures can be manufactured, and a polymer having a high dissolution temperature and a low glass transition temperature (Tg) can exhibit great advantages in processing and properties.

[0164] The prepolymer produced in the above slurry polymerization reaction may account for 10 wt% to 60 wt% of the total amount of the final polymer produced. For example, the prepolymer may be 20 wt% to 50 wt% or 30 wt% to 50 wt% of the total amount of the final polymer. By adjusting the weight ratio of the prepolymer to the total amount of the final polymer within the above range, the overall density is increased, and a relatively high-density shell portion is firmly formed without deteriorating the physical properties of the final polymer, so that the polymer produced in the gas phase polymerization reactor is hardly present on the outside, thereby improving process stability.

[0165] In one embodiment, the vapor phase polymerization reaction is performed according to ASTM 3417-83. 15 (15 wt% melting initiation temperature) can be performed at a temperature below. Specifically, the MIT 15 The temperature below is to control the temperature of each reaction low to secure process stability, but to set an appropriate temperature range, and the above MIT 15 The temperature below was measured using a DSC device according to the ASTM 3417-83 method, and was measured based on the part where 15 wt% melt area percent appears in the 1st scan from 25 ℃ to 200 ℃ under the condition of 10 ℃ / min.

[0166] For example, in the above gas phase polymerization reaction, MIT 15 The temperature below may be 40°C to 80°C, 40°C to 70°C or 40°C to 65°C. The MIT 15Controlling the gas phase polymerization reaction at the same temperature as the temperature can cause the polymer to clump and reduce the process stability. On the other hand, if the reactor temperature is operated too low to ensure the process stability, there is a disadvantage of very low production. In addition, in the process of manufacturing polyolefin polymers with high comonomer content, a situation where the comonomer ratio is locally high when the production volume increases occurs, which increases the adhesiveness of the polymer and creates a heterogeneous polymer, which can be a factor in process trouble. MIT within the above range 15 This problem can be prevented by controlling the temperature of the gas phase polymerization reaction.

[0167] In one embodiment, when the slurry polymerization reaction is placed in front of a gas phase polymerization reactor, not only can the metallocene catalyst be prevented from being directly exposed to gas phase polymerization conditions, but the slurry polymerization reaction can also increase the size of the polymer, which is helpful for process stability. On the other hand, when a low-density prepolymer is produced in a slurry polymerization reaction, the polymer having the properties of a polyolefin elastomer increases on the outside, and the polymer as a whole has a sticky characteristic, which can cause a problem of lowering process stability.

[0168] In one embodiment, the slurry polymerization reaction may produce a prepolymer having a hollow structure to form a shell portion of the final polymer, and the gas phase polymerization reaction may fill the hollow portion of the prepolymer with a product having a higher density than the prepolymer to form a core portion of the final polymer.

[0169] Here, the final polymer may be the polyolefin polymer described above. Specifically, through the slurry polymerization step, the density is 0.890 g / cm. 3 0.940 g / cm 3 The above shell is formed, and through the above gas phase polymerization step, the density is 0.857 g / cm 3 0.910 g / cm3 It can form a core part.

[0170] The final polymer may have one or more of the following properties (a) to (h). For example, the polyolefin polymer may have two or more or all of the following properties (a) to (h).

[0171] (a) Melt flow index (MIE (2.16 kg load, 190°C)) of 0.1 g / 10 min to 5.0 g / 10 min;

[0172] (b) 0.870 g / cm 3 0.900 g / cm 3 density of

[0173] (c) Two or more melting temperatures (T m )

[0174] (d) First melting temperature (T m1 ) and the second melting temperature (T m2 ), and the difference between the first melting temperature and the second melting temperature is 30 ℃ to 70 ℃.

[0175] (e) First melting temperature (T m1 ) and the second melting temperature (T m2 ), the first melting temperature is 45°C to 85°C, and the second melting temperature is 80°C to 125°C.

[0176] (f) Two or more crystallization temperatures (T c )

[0177] (g) First crystallization temperature (T c1 ) and the second crystallization temperature (T c2 ), the first crystallization temperature is 40 ℃ to 100 ℃, and the second crystallization temperature is 70 ℃ to 110 ℃.

[0178] (h) In a temperature rising elution fractionation (TREF) chromatogram, two or more peaks are shown at a temperature of 35°C or higher, and the percentage value of the graph area above 60°C divided by the total graph area is 5% or more.

[0179] In one embodiment, the shell portion, i.e. the prepolymer prepared in the slurry polymerization reactor, has a density of, for example, 0.890 g / cm 3 0.940 g / cm 3 , 0.895 g / cm 3 0.930 g / cm 3 or 0.900 g / cm 3 0.922 g / cm 3 It could be.

[0180] The melt flow index (MIE (2.16 kg load, 190°C)) of the above shell portion may be, for example, 0.01 g / 10 min to 5.0 g / 10 min, 0.05 g / 10 min to 3.5 g / 10 min, or 0.05 g / 10 min to 2.0 g / 10 min.

[0181] The melting temperature of the shell portion may be, for example, 80°C to 125°C, 90°C to 120°C or 95°C to 110°C.

[0182] The temperature rising elution fractionation (TREF) chromatogram of the above shell portion may have one peak at a temperature of 60°C or higher.

[0183] In one embodiment, the density of the core formed inside the hollow interior of the prepolymer through the above-described gas phase polymerization reaction is, for example, 0.857 g / cm 3 0.910 g / cm 3 , 0.855 g / cm 3 0.900 g / cm 3 or 0.857 g / cm 3 0.898 g / cm 3 It could be.

[0184] The melting temperature of the core portion may be, for example, 45°C to 85°C, 50°C to 85°C, or 60°C to 70°C.

[0185] The melt flow index (MIE (2.16 kg load, 190°C)) of the final polymer may be, for example, 0.1 g / 10 min to 5.0 g / 10 min, 0.5 g / 10 min to 4 g / 10 min, or 0.6 g / 10 min to 3.2 g / 10 min. In the final polymer, the weight ratio of the core portion and the shell portion may be 40:60 to 90:10, 50:50 to 80:20, or 50:50 to 70:30. By forming the core portion and the shell portion at a weight ratio within the above range, it is possible to provide a final polymer having the characteristics of a polyolefin elastomer with a low density, while at the same time preventing the process stability from being deteriorated due to the sticky or wet properties that hinder fluidization.

[0186] As described above, the shell and core have different properties, so that two or more characteristics, such as melting temperature and crystallization temperature, appear in one polyolefin polymer.

[0187] As an example, the polymerization method of the polyolefin may include a slurry polymerization step of subjecting a feed composition including a monomer and a comonomer to a slurry polymerization reaction in the presence of the catalyst to produce a slurry reaction product including a prepolymer; and a gas phase polymerization step of subjecting the slurry reaction product obtained above, or the slurry reaction product and the feed composition to a gas phase polymerization reaction to produce a final polymer.

[0188] The following Figure 2a is a diagram illustrating a polyolefin polymerization method according to one embodiment. Specifically, referring to the following Figure 2a, the polyolefin polymerization method may be performed sequentially through a slurry polymerization reaction and a gas phase polymerization reaction.

[0189] As another example, the polymerization method of the polyolefin may include a first slurry polymerization step of subjecting a feed composition including a monomer and a comonomer to a slurry polymerization reaction in the presence of a catalyst to produce a slurry reaction product including a prepolymer; a first gas phase polymerization step of subjecting the slurry reaction product obtained above, or the slurry reaction product obtained above and the feed composition to a first gas phase polymerization reaction to produce a first gas phase reaction product including a final polymer; and a second gas phase polymerization step of subjecting the first gas phase reaction product obtained above, or the first gas phase reaction product obtained above and the feed composition to a second gas phase polymerization reaction to produce a second gas phase reaction product including the final polymer.

[0190] As another example, the method for polymerizing the polyolefin may include a first slurry polymerization step of subjecting a feed composition comprising a monomer and a comonomer to a first slurry polymerization reaction in the presence of a catalyst to produce a first slurry reaction product comprising a prepolymer; a second slurry polymerization step of subjecting the first slurry reaction product obtained above, or the first slurry reaction product and the feed composition to a second slurry polymerization reaction to produce a second slurry reaction product comprising a prepolymer; a first gas phase polymerization step of subjecting the second slurry reaction product obtained above, or the second slurry reaction product obtained above, and the feed composition to a first gas phase polymerization reaction to produce a first gas phase reaction product comprising a final polymer; and a second gas phase polymerization step of subjecting the first gas phase reaction product obtained above, or the first gas phase reaction product and the feed composition to a second gas phase polymerization reaction to produce a second gas phase reaction product comprising a final polymer.

[0191] The following Figure 2d is a diagram illustrating a polyolefin polymerization method according to one embodiment. Specifically, referring to the following Figure 2d, the polyolefin polymerization method may sequentially perform a first slurry polymerization reaction, a second slurry polymerization reaction, a first gas phase polymerization reaction, and a second gas phase polymerization reaction.

[0192] In one embodiment, the first gas phase reaction product generated in the first gas phase polymerization reaction is filtered through a filter to separate unreacted gas and polymer, and the separated polymer is used to perform a second gas phase polymerization reaction, and the unreacted gas can be reused in the first slurry polymerization reaction and / or the second slurry polymerization reaction.

[0193] Operating the above-described gas-phase polymerization reaction at too low a temperature has the disadvantage of significantly lowering production yields. Furthermore, during the manufacturing process of polyolefin polymers with high comonomer content, increased production can result in locally high comonomer ratios. This can increase polymer viscosity, leading to the formation of heterogeneous polymers and potentially causing process issues. The present invention utilizes a high-sorption mode to reduce polymer viscosity under high comonomer concentration conditions.

[0194] As a specific example, the first gas phase polymerization reaction may not be operated in a high sorption mode, and the second gas phase polymerization reaction may be operated in a high sorption mode. The second gas phase polymerization reaction may be operated under conditions of temperature and pressure at which the injected gas is condensed, while the gas discharged from the reactor is not condensed.

[0195] For reference, the above-described gas phase polymerization reaction can be performed using a circulation line extending from the upper part of the gas phase polymerization reactor and connected to the lower part of the gas phase polymerization reactor to circulate a circulation gas stream, a compressor provided in the circulation line, and a heat exchanger provided at a later stage than the compressor based on the flow direction of the circulation gas stream in the circulation line. In the high-sorption mode, the sorbent can be used in an amount of 0.1 to 30 parts by weight, 2 to 20 parts by weight, or 3 to 15 parts by weight, based on 100 parts by weight of the total circulation gas stream.

[0196] The sorption agent used when the above second gas phase polymerization reaction is operated in a high sorption mode may include propane, isobutane, isopentane, hexane, and the like.

[0197] When polymerizing polyolefin including the above two slurry polymerization steps and two gas phase polymerization steps, the density is 0.890 g / cm through the above two slurry polymerization steps. 3 0.940 g / cm 3 The above shell portion is formed, and through the first gas phase polymerization step, the density is 0.887 g / cm 3 0.898 g / cm 3 The core part is formed, and the density is 0.857 g / cm through the second gas phase polymerization step. 3 0.886 g / cm 3 The core part can be formed.

[0198] Through the above two slurry polymerization steps, the density is, for example, 0.890 g / cm 3 0.940 g / cm 3 , 0.895 g / cm 3 0.930 g / cm 3 or 0.900 g / cm 3 0.922 g / cm 3 A one-person shell can be formed.

[0199] Through the above first phase polymerization step, the density is 0.887 g / cm 3 0.898 g / cm 3 or 0.888 g / cm 3 0.897 g / cm 3 It can form a core part.

[0200] Through the above second phase polymerization step, the density is 0.857 g / cm 3 0.886 g / cm 3 or 0.857 g / cm 3 0.884 g / cm 3 It can form a core part.

[0201] In this way, a polyolefin polymer can be manufactured by forming a shell portion with a relatively high density through a slurry polymerization reaction, forming a core portion with a lower density than the slurry polymerization reaction through a first gas phase polymerization reaction, and forming a core portion with an even lower density than the first gas phase polymerization reaction through a second gas phase polymerization reaction. This difference in density gradient can improve process stability when the first and second gas phase polymerization reactions are performed in the future by forming a prepolymer with a relatively high density in the slurry polymerization reaction compared to the gas phase polymerization reaction. The manufactured polyolefin polymer can have a high melting temperature and a low melting temperature, that is, two or more melting temperatures due to the density gradient, and can have a low glass transition temperature. Due to these characteristics of the polyolefin polymer, the rotation rate increases during molding, thereby increasing processing productivity, and the low glass transition temperature can improve physical properties such as rebound resilience.

[0202]

[0203] Below, specific embodiments of the present invention are presented. However, the following examples are intended solely to illustrate or explain the present invention and should not be construed as limiting it. Furthermore, any details not described herein are technically feasible to those skilled in the art, and therefore, their description is omitted.

[0204] (Manufacture of polyolefin polymers)

[0205] Examples 1 to 4 and Comparative Examples 1 to 2

[0206] A polyolefin polymer, specifically linear low-density polyethylene, was produced using one slurry polymerization reactor and one gas phase polymerization reactor. The operating conditions of each reactor are as shown in Table 1 below.

[0207] A polymerization reaction was performed in a batch polymerization reactor by simulating slurry polymerization and gas phase polymerization conditions using a catalyst composition prepared as a basic combination of a metallocene catalyst, methylaluminoxane (MAO), and a porous support.

[0208] To control the polymerization temperature, a 2L stainless steel autoclave reactor equipped with a jacket capable of supplying external cooling water was heated from room temperature to 110°C, purged with nitrogen, and then purged with 400 ml of isobutane.

[0209] After temperature control, 1.5 ml of 0.2 M triethylaluminum (TEAL), 2.5 ml (1.1 mmol in hexane) of antistatic agent (Statsafe® 6000, Innospec), and 1 L of isobutane were added to the reactor.

[0210] Then, ethylene, 1-hexene (wt%, amount of 1-hexene input relative to ethylene input), and hydrogen (mg / kgC2, amount of hydrogen input (mg) relative to 1 kg of ethylene input) were introduced, and a supported catalyst was introduced into the reactor. The slurry polymerization reaction was carried out according to the polymerization conditions shown in Table 1 below. During the polymerization, the ethylene partial pressure was maintained constant, and 1-hexene and hydrogen were continuously introduced in conjunction with ethylene. After the slurry polymerization was completed, unreacted 1-hexene and isobutane were discharged.

[0211] For the gas phase polymerization reaction, nitrogen was injected into the gas phase polymerization reactor as a diluent at 100 psi, 250 ppm of an antistatic agent was injected, and the temperature was controlled at 48 ℃.

[0212] After temperature control, a gas phase polymerization reaction was carried out according to the polymerization conditions shown in Table 1 below, and after completion of the reaction, unreacted gas was discharged, the reactor was opened, and a linear low density polyethylene (LLDPE) resin with free flow was obtained as the final polymer, and its physical properties were measured and presented.

[0213] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Slurry polymerization reactor Catalyst injection amount (g) 0.18 0.18 0.18 0.18 0.18 0.12 Reactor temperature (℃) 60 60 60 60 60 47 Reactor pressure (K / G) 13.1 13.1 113.1 113.1 113.1 110.8 0.2 M TEAL (ml) 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Ethylene partial pressure (K / G) 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 Hydrogen injection amount (ppm) 40 40 30 30 40 10 1-hexene Injection amount (wt%) 101010101035MIE (g / 10min) 1.411.301.301.301.302.15Density (D) (g / ㎤) 0.92060.91550.91550.91550.91550.8975T m (℃)113.1115.4115.4115.4115.4N / AT c(℃)99.8101.8101.8101.8101.8N / AGas-phase polymerization reactorReactor temperature(℃)484848486055Reactor pressure(K / G)11.711.711.711.711.713Ethylene partial pressure(K / G)4.84.84.84.84.86.2Hydrogen injection amount(ppm)0000001-Hexene injection amount(wt%)355560705550MIE(g / 10min) 1) 1.680.680.630.89N / A1.00SR(F / E)19.822.523.924.7N / A19.7Density(D)(g / cm3)0.89660.88230.87860.8739N / A0.8816T m (℃)82.2 / 113.557.9 / 115.957.6 / 116.551.3 / 118.9N / A56.4T c (℃)96.2 / 108.386.5 / 108.484.9 / 107.484.6 / 106.2N / A40.6 / 96.7T g (℃)-45-52.7-54.0-58.2N / A-53.0MIT 15 (℃)68.660.161.859.6N / AN / AIndividual density (D)(g / ㎤)0.87380.86880.86370.8572N / A0.8750Fraction (weight%)507070707070B.D0.390.400.390.36N / A0.3260℃ or more TREF Fraction (%)50252523N / AN / A

[0214] 1) MIE in a gas phase polymerization reactor is a measurement value for the final polymer.

[0215]

[0216] In Table 1 above and Table 2 below, the measurement method for each characteristic is shown below.

[0217] Melt flow index (MIE, MI2.16): Measured according to ASTM D1238 at 190℃ and 2.16 kg load.

[0218] High load melt flow index (MIF, MI21.6): Measured according to ASTM D1238 at 190℃ and 21.6 kg load.

[0219] Melt flow rate ratio (SR, MFRR): calculated as MIF / MIE (F / E).

[0220] Density: Measured by the density gradient method according to ASTM D1505.

[0221] BD: Bulk density (apparent density) was measured according to ASTM D1895.

[0222] Molecular weight and molecular weight distribution: The following measurements were performed using a gel permeation chromatography-RI (GPC-RI; Polymer Laboratory Inc. 220 System) equipped with a refractive index detector (RI Detector). Two Olexis columns and one Guard column were used, and the column temperature was maintained at 160°C. Calibration was performed using a standard polystyrene set from Polymer Laboratory Inc. Trichlorobenzene containing 0.0125 wt% antioxidant (BHT) was used as the eluent, and the sample concentration was 1.0 mg / mL. The measurement was performed for 27 minutes under the conditions of an injection amount of 0.2 mL and a pump flow rate of 1.0 mL / min. The number average molecular weight (Mn), weight average molecular weight (Mw), and Z-average molecular weight (Mz) were calculated by converting them to polyethylene after universal calibration using polystyrene standard materials Easical A and Easical B (Agilent).

[0223] Melting temperature (T m ), crystallization temperature (T c ) : It was measured using a DSC device according to the ASTM 3417-83 method, and the value appearing in the 2nd scan was used in the temperature range of 25 to 200℃ at 10℃ / min.

[0224] Glass transition temperature (T g) : It was measured using a DSC device according to the ASTM 3417-83 method, and the value appearing in the 2nd scan was used in the temperature range of -80 to 200℃ under the condition of 40℃ / min.

[0225] MIT 15 : It was measured using a DSC device according to the ASTM 3417-83 method, and the part where 15 wt% melt area percent appears in the 1st scan from 25 to 200℃ under the condition of 10℃ / min was used as the standard.

[0226] Comonomer (wt%): Analyzed and calculated using 13C NMR according to ASTM D5017.

[0227] Temperature Rising Elution Fractionation (TREF): The analysis was performed using Cross-Fractionation Chromatography (CFC; PolymerChar CFC-2) equipment as follows. Two Olexis columns and one Guard were used as separation columns, the column temperature was maintained at 150 ℃, and calibration was performed using a standard polystyrene set from Polymer Laboratory Inc. Trichlorobenzene containing 0.0125 wt% antioxidant (BHT) was used as the eluent, the sample concentration was 75 mg / mL, and the pump flow rate was 1.0 mL / min. After sample injection, the oven and sample temperatures were increased to 150 ℃ at a heating rate of 40 ℃ / min, maintained at 150 ℃ for 60 minutes, and then the sample temperature was decreased to 95 ℃ at a cooling rate of 40 ℃ / min. After maintaining at 95 ℃ for 45 minutes, it was cooled again to 30 ℃ at a cooling rate of 0.5 ℃ / min and maintained for 30 minutes. Thereafter, while increasing the temperature of the sample from 35 ℃ to 120 ℃, it was divided into 22 temperature-specific fractions at 4 ℃ intervals, 0.5 mL of sample was injected into each fraction, and the eluted fractions were passed through a TREF column and an Olexis column to obtain the TREF value and molecular weight simultaneously. The molecular weight was calculated by converting it to polyethylene after universal calibration using polystyrene standards Easical A and Easical B (Agilent). Data processing was performed using the analysis program "CFC Calibration" attached to the device, and the analysis took approximately 600 minutes, and an infrared spectrometer was used as a detector.

[0228] Sole density: Calculated using Equation 1 below.

[0229] [Formula 1]

[0230]

[0231] In the above equation 1, d is the density of the final polymer, d1 and m1 are the sole density and fraction (weight %) of the polymer produced in the first slurry polymerization reactor, respectively, d2 and m2 are the sole density and fraction (weight %) of the polymer produced in the second slurry polymerization reactor, respectively, d3 and m3 are the sole density and fraction (weight %) of the polymer produced in the first gas phase polymerization reactor, respectively, d4 and m4 are the sole density and fraction (weight %) of the polymer produced in the second gas phase polymerization reactor, respectively, and m1+m2+m3+m4 = 1.

[0232] In Examples 1 to 4 and Comparative Examples 1 to 2, which used one slurry polymerization reactor and one gas phase polymerization reactor, it was assumed that a first slurry polymerization reactor and a second gas phase polymerization reactor were used, and factors related to the second slurry polymerization reactor and the first gas phase polymerization reactor were excluded from the formula and calculated.

[0233] Examples 5 to 7 and Comparative Example 3

[0234] A polyolefin polymer, specifically, linear low-density polyethylene, was produced using a catalyst composition (M-Cat') prepared by combining a metallocene catalyst, methylaluminoxane (MAO), and a porous support, using two slurry polymerization reactors and two gas phase polymerization reactors. The operating conditions of each reactor are as shown in Table 2 below.

[0235] The fluidized beds of the first and second slurry polymerization reactors are composed of polymer particle granules. 1-Butene, ethylene, and hydrogen are mixed together in a pipe and injected into a circulation line. The injected composition and the properties of the produced prepolymer are shown in Table 2 below.

[0236] The injection concentrations of ethylene, hydrogen, and 1-butene in the first and second gas phase polymerization reactors were controlled to maintain the compositions shown in Table 2 below. In addition, the prepolymer was supplied in an amount of 5 to 10 wt% of the total weight of the polymerization composition (prepolymer + ethylene + 1-butene), and the remaining molar percentage of ethylene, hydrogen, and 1-butene in the component concentrations of the first and second gas phase polymerization reactors in Table 2 below is propane, which is a diluent.

[0237] The concentrations of all gases were measured using online gas chromatography of the gases in the circulating gas stream. The reaction products discharged from the first gas phase polymerization reactor passed through a filter to separate the unreacted gas and polymer, and the polymer was transferred to the second gas polymerization reactor, and the separated unreacted gas was injected into the first slurry polymerization reactor through a purification tower. The slurry polymerization reactor and the gas phase polymerization reactor used propane as a diluent, and the copolymer of ethylene and 1-butene produced by the catalytic reaction was continuously discharged and operated so that the fluidized bed height of the gas phase polymerization reactor was maintained constant. To maintain a constant operating temperature, the heat generated by the polymerization reaction was removed by controlling the temperature of the circulating gas using a heat exchanger.

[0238] Afterwards, the reaction product was discharged from the second gas phase polymerization reactor, and the reaction product was subjected to processes such as degassing and drying to obtain linear low-density polyethylene (LLDPE) resin as the final polymer, and its physical properties were measured and shown in Table 2.

[0239] ClassificationExample 5Example 6Example 7Comparative Example 3First slurry polymerization reactorCatalyst injection amount (kg / h)3.53.13.1-Reactor temperature (℃)504747-Reactor pressure (K / G)25.425.425.4-Ethylene injection amount (kg / h)600600550-Hydrogen injection amount (g / h)0020-Comonomer molar ratio0.1580.2680.192-MIE (g / 10min)0.520.071.93-Density (D)(g / cm3)0.91800.90680.9098-Second slurry polymerization reactorReactor temperature (℃)504646-Reactor pressure (K / G)242424-Ethylene Injection amount (kg / h) 300 300 250 - Hydrogen injection amount (g / h) 000 - Comonomer molar ratio 0.07 3 0.15 0.125 - MIE (g / 10 min) 0.7 2 0.4 2 1.53 - Density (D) (g / cm3) 0.9 1 7 5 0.9 7 0 0.9 0 8 4 - First gas phase polymerization reactor Reactor temperature (℃) 4 3 4 1 4 1 - Reactor pressure (K / G) 1 4 1 2.8 1 2.6 - Ethylene injection amount (kg / h) 1 5 0 1 5 5 0 1 5 1 - Ethylene concentration (mol%) 4.6 3.7 4.4 - Hydrogen concentration (mol ppm) 1 7 3 3 9 - Comonomer Molar ratio 0.074 0.102 0.096 - MIE (g / 10 min) 0.95 1.143.11 - SR (F / E) 17.4 17.7 16.9 - Density (D) (g / cm3) 0.90 46 0.895 20.897 3 - Sole density (D) (g / cm3) 0.89 70 0.88 8 30.89 14 - Second gas phase polymerization reactor Reactor temperature (℃) 434 141 - Reactor pressure (K / G) 1413.7 13.1 - Ethylene injection amount (Kg / h) 522 5500 1572 8 - Ethylene concentration (mol%) 7.6 8.4 7.4 - Hydrogen concentration (mol ppm) 567 9 110 - Comonomer molar ratio 0.148 0.150 0.150 - MIE (g / 10 min) 1) 0.951.073.041.01SR(F / E)15.916.816.940.4Density(D)(g / cm3)0.89000.88510.88560.8873Individual density(D)(g / cm3)0.88340.88050.8809-Mw133,985123,98491,888N / AT m (℃)68.9 / 105.662.2 / 95.363.6 / 98.773.6T c(℃)49.3 / 87.044.7 / 74.944.3 / 77.660.1 / 72.7T g (℃)-42.7-44.1-44.5-40.9MIT 15 (℃)52.648.546.1N / AComonomer (wt%)17.919.620.2N / AFraction (wt%)686871-60℃ or higherTREFFraction (%)181083

[0240] 1) MIE in the second phase polymerization reactor is a measurement value for the final polymer.

[0241]

[0242] In Table 2 above, the comonomer refers to 1-butene, and the comonomer molar ratio refers to the molar ratio of 1-butene to the total amount of ethylene and 1-butene.

[0243]

[0244] (Experimental example)

[0245] Experimental Example 1: Structural confirmation of polyolefin polymers

[0246] 1. Cross-section of the prepolymer

[0247] A cross-section of the prepolymer included in the reaction product generated in the slurry polymerization reactor in Example 2 was photographed using a scanning electron microscope (SEM), and the photographed image is shown in Figure 4a below.

[0248] As shown in Fig. 4a, it can be seen that a prepolymer having a hollow structure was created through the slurry polymerization reaction, thereby forming the shell portion of the final polymer.

[0249] 2. Cross-section of the final polymer

[0250] A cross-section of the final polymer contained in the reaction product generated in the gas phase polymerization reactor in Example 2 was photographed using a scanning electron microscope (SEM), and the photographed image is shown in Fig. 4b below. The densities of the shell and core portions are shown in the image.

[0251] Looking at Figure 4b, it was confirmed that a relatively low-density core portion was formed in the hollow space of the prepolymer through the above-mentioned gas phase polymerization reaction.

[0252] 3. Cross-section of the final polymer before and after dissolution in xylene

[0253] Using a scanning electron microscope (SEM), a cross-section of the final polymer included in the reaction product generated in the gas phase polymerization reactor in Example 2 and a cross-section after dissolving the final polymer in a xylene solution were photographed, and the photographed images are shown in Fig. 4c below. Specifically, the left image of Fig. 4c is an image taken before dissolving the final polymer in a xylene solution, and the right image is an image after dissolving the final polymer in a xylene solution.

[0254] The above xylene dissolution experiment is an experiment that can confirm that the low-density, high-MI part is dissolved and eluted in xylene, and as shown in Fig. 4c, when the final polymer is dissolved in xylene, it can be confirmed that only the core part with a relatively low density is dissolved, and the shell part with a high density of about 0.916 is maintained without being dissolved. Through this, it can be confirmed that the final polymer according to the present invention has a core-shell structure in which a core part with a low density is formed on the inside and a shell part with a high density is formed on the outside surrounding the core part.

[0255] Experimental Example 2: TREF Verification of Polyolefin Polymers

[0256] The temperature-dependent TREF values ​​of the final polymers manufactured in Examples 1 to 7 and Comparative Example 3 were measured by the above-described method to derive a temperature-increasing elution fractionation (TREF) chromatogram, which can be confirmed through Tables 1 and 2 above. Meanwhile, the temperature-increasing elution fractionation (TREF) chromatogram derived for the final polymers manufactured in Example 5 and Comparative Example 3 can also be confirmed through Figure 5 below.

[0257] Looking at Table 1, Table 2, and Figure 5, it can be seen that the final polymers according to Examples 1 to 7 exhibit two peaks at a temperature of 35°C or higher, and the percentage value of the graph area at 60°C or higher divided by the total graph area is 5% or higher. On the other hand, the final polymer according to Comparative Example 3 exhibits one peak at a temperature of 35°C or higher, and the percentage value of the graph area at 60°C or higher divided by the total graph area is 3%.

[0258] [Explanation of symbols]

[0259] 100: First slurry polymerization reactor

[0260] 110: Catalyst injection

[0261] 120: Feedstream injection

[0262] 130: Circulation pump

[0263] 140: Heat exchanger

[0264] 150: Polymer discharge

[0265] 151: First prepolymer discharge

[0266] 200: Second slurry polymerization reactor

[0267] 210: Injection of first prepolymer

[0268] 220: Feedstream injection

[0269] 230: Circulation pump

[0270] 240: Heat exchanger

[0271] 250: Second prepolymer discharge

[0272] 300: First gas phase polymerization reactor

[0273] 310: Prepolymer injection

[0274] 320: Feedstream injection

[0275] 330: Compressor

[0276] 340: Heat exchanger

[0277] 350: Feedstream injection

[0278] 360: First final polymer discharge

[0279] 400: Second gas phase polymerization reactor

[0280] 410: First final polymer injection

[0281] 420: Feedstream injection

[0282] 430: Compressor

[0283] 440: Heat exchanger

[0284] 450: Feedstream injection

[0285] 460: Second final polymer discharge

Claims

1. A polyolefin polymerization system comprising one or more slurry polymerization reactors for subjecting a feed stream supplied in the presence of a catalyst to a slurry polymerization reaction to produce a slurry reaction product including a prepolymer, The above feed stream comprises monomers and comonomers, The above slurry polymerization reactor A loop comprising one or more reactors; One or more polymer discharge ports; One or more monomer inlets; one or more heat exchangers; and characterized by including one or more circulation pumps, Polymerization system of polyolefin.

2. In paragraph 1, A polyolefin polymerization system characterized in that a shell portion is formed through the above slurry polymerization reactor.

3. In paragraph 1, A polyolefin polymerization system characterized in that the above heat exchanger is of a shell and tube type.

4. In paragraph 3, The above heat exchanger has a cooling water flow rate of 1 m / s or more, preferably 3 m / s or more, and a heat transfer efficiency of 0.3 Mcal / m 2 ×hr×K or more, preferably 0.6Mcal / m 2 A polymerization system of polyolefin, characterized in that it is ×hr×K or more.

5. In paragraph 1, A polyolefin polymerization system characterized in that it additionally includes at least one gas phase polymerization reactor that receives the slurry reaction product, or the slurry reaction product and a feed stream, and performs a gas phase polymerization reaction to produce a gas phase reaction product including a final polymer.

6. In paragraph 5, A polyolefin polymerization system characterized in that a core portion is formed through the above-mentioned gaseous polymerization reactor.

7. In paragraph 5, The final polymer has two or more density distributions, including a core portion and a shell portion having a higher density than the core portion, A polyolefin polymerization system wherein the operating temperature of the slurry polymerization reactor is 20°C to 70°C and is higher than the operating temperature of the gas phase polymerization reactor.

8. In paragraph 7, The density of the core part is 0.857 g / cm 3 0.910 g / cm 3 And, The density of the above shell is 0.890 g / cm 3 0.940 g / cm 3 And, The density of the shell portion is higher than the density of the core portion. Polymerization system of polyolefin.

9. In paragraph 7, The above final polymer is a polymerization system of polyolefin having any one or more of the following properties (a) to (h); (a) Melt flow index (MIE (2.16 kg load, 190°C)) of 0.1 g / 10 min to 5.0 g / 10 min; (b) 0.870 g / cm 3 0.900 g / cm 3 density of (c) Two or more melting temperatures (T m ) (d) First melting temperature (T m1 ) and the second melting temperature (T m2 ), and the difference between the first melting temperature and the second melting temperature is 30 ℃ to 70 ℃. (e) First melting temperature (T m1 ) and the second melting temperature (T m2 ), the first melting temperature is 45°C to 85°C, and the second melting temperature is 80°C to 125°C. (f) Two or more crystallization temperatures (T c ) (g) First crystallization temperature (T c1 ) and the second crystallization temperature (T c2 ), the first crystallization temperature is 40°C to 100°C, and the second crystallization temperature is 70°C to 110°C. (h) In a temperature rising elution fractionation (TREF) chromatogram, two or more peaks are shown at a temperature of 35°C or higher, and the percentage value of the graph area above 60°C divided by the total graph area is 5% or more.

10. In paragraph 5, A first slurry polymerization reactor for subjecting a feed stream supplied in the presence of a catalyst to a slurry polymerization reaction to produce a slurry reaction product including a prepolymer; and A polyolefin polymerization system comprising a first gas phase polymerization reactor that receives the slurry reaction product, or the slurry reaction product and a feed stream, and performs a gas phase polymerization reaction to produce a gas phase reaction product including a final polymer.

11. In paragraph 5, A first slurry polymerization reactor for subjecting a feed stream supplied in the presence of a catalyst to a slurry polymerization reaction to produce a first slurry reaction product including a prepolymer; A second slurry polymerization reactor that receives the first slurry reaction product, or the first slurry reaction product and a feed stream, from the first slurry polymerization reactor and performs a slurry polymerization reaction to produce a second slurry reaction product including a prepolymer; A first gas phase polymerization reactor that receives a second slurry reaction product from the second slurry polymerization reactor, or the second slurry reaction product and a feed stream, and performs a gas phase polymerization reaction to produce a first gas phase reaction product including a final polymer; and A polyolefin polymerization system comprising a second gas phase polymerization reactor that receives a first gas phase reaction product, or the first gas phase reaction product and a feed stream, from the first gas phase polymerization reactor and performs a gas phase polymerization reaction to produce a second gas phase reaction product including a final polymer.

12. In paragraph 1, The above catalyst is a polymerization system of polyolefin which is a metallocene single catalyst.

13. In paragraph 1, The above monomer is a polymerization system of polyolefin which is ethylene.

14. In paragraph 1, A polymerization system of a polyolefin wherein the above monomer is at least one selected from the group consisting of 1-butene, 1-hexene, 1-pentene, 4-methyl-1-pentene and 1-octene.

15. In paragraph 7, The operating temperature of the above slurry polymerization reactor is 40°C to 60°C, A polyolefin polymerization system in which the operating temperature of the above-mentioned gaseous polymerization reactor is 30°C to 50°C.

16. In paragraph 7, The above gas phase polymerization reactor has an MIT measured according to ASTM 3417-83. 15 A polymerization system for polyolefins operated at a temperature below (15 wt% melting initiation temperature).

17. In paragraph 11, The above second gas phase polymerization reactor is operated in high sorption mode, A polymerization system for polyolefin in which the sorption agent is used in the above high-sorption mode in an amount of 0.1 to 30 parts by weight relative to 100 parts by weight of the total circulating gas stream.

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