Preparation method of polyolefin-polystyrene multi-block copolymer

Abstract

The present invention relates to a method for preparing a polyolefin-polystyrene multi-block copolymer having a uniform structure and exhibiting excellent physical properties by continuous coordination polymerization and batch anionic polymerization.

Description

Technical Field

[0001] This application claims priority based on Korean Patent Application No. 10-2020-0109159, filed on August 28, 2020, and Korean Patent Application No. 10-2021-0111575, filed on August 24, 2021, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a method for preparing a polyolefin-polystyrene multi-block copolymer having a uniform structure and exhibiting excellent physical properties through continuous coordination polymerization and batch anionic polymerization. Background Art

[0003] Block copolymers are materials widely used in high-tech devices and common plastics, and their research and development are being actively carried out. In particular, styrene-olefin copolymer resins containing polyolefin (PO) blocks and polystyrene (PS) blocks have excellent properties such as heat resistance, light resistance, and elasticity, and can be used in a variety of technical fields.

[0004] Polyolefin-polystyrene block copolymers, such as styrene-ethylene-butylene-styrene (SEBS) or styrene-ethylene-propylene-styrene (SEPS), currently have a market scale of hundreds of thousands of tons in the world. Generally, polystyrene-block-poly(ethylene-co-1-butene)-block-polystyrene (SEBS) triblock copolymer can be cited as a styrene-olefin copolymer resin. In the structure of the SEBS triblock copolymer, the hard polystyrene domains are separated from the soft poly(ethylene-co-1-butene) matrix and act as physical crosslinking sites, showing the properties of a thermoplastic elastomer. According to these properties, SEBS is more widely used in product categories that require rubber and plastics, and as the scope of use expands, the demand has increased significantly.

[0005] Conventional SEBS is prepared by a two-step reaction including anionic polymerization of styrene and butadiene and hydrogenation of the resulting SBS. Conventional SEPS is also prepared by a two-step reaction including anionic polymerization of styrene and isoprene and hydrogenation of the resulting SIS. The process of saturating all double bonds contained in the polymer main chain through the hydrogenation reaction as described above is very costly, and the unit cost of SEBS and SEPS is significantly increased compared to SBS and SIS before the hydrogenation reaction. Therefore, these aspects may limit market expansion. In addition, through the hydrogenation reaction, it is almost impossible to saturate all double bonds in the polymer chain, and commercial SEB and SEP include some residual double bonds, and their presence usually causes problems.

[0006] Therefore, in order to prepare a block copolymer that exhibits thermoplastic elastomer properties through a multi-block structure having three or more blocks and is industrially useful, a technique has been developed for preparing a polyolefin-polystyrene diblock copolymer from olefin monomers and styrene monomers by a one-pot method by carrying out coordination polymerization of olefin monomers to form a polyolefin block and then carrying out anionic polymerization with styrene monomers to form a polyolefin-polystyrene multi-block.

[0007] However, if the coordination polymerization and anionic polymerization are carried out batchwise, it is difficult to remove heat from the batch reactor, and it is difficult to recycle and reuse the reactants (e.g., unreacted monomers), and the operating cost may increase uneconomically. In addition, the uniform control of the reactant concentration in the reactor is limited, and there is a problem that the physical properties of the polyolefin-polystyrene multi-block copolymer deteriorate and become non-uniform, which are manifested as other tasks.

[0008] [Prior Art Documents]

[0009] [Patent Documents]

[0010] Korean Registered Patent No. 10-1657925 Summary of the Invention

[0011] Technical Problem

[0012] An object of the present invention is to provide a method for preparing a polyolefin-polystyrene multi-block copolymer having a uniform structure and exhibiting excellent physical properties by sequentially carrying out continuous coordination polymerization of olefin monomers and batch anionic polymerization of styrene monomers.

[0013] Technical Solution

[0014] To solve the above tasks, the present invention provides a method for preparing a polyolefin-polystyrene multi-block copolymer, the method comprising: (S1) preparing a polyolefin by carrying out coordination polymerization of ethylene and α-olefin monomers while continuously injecting a hafnium compound, an organozinc compound, an organic solvent, ethylene gas, and an α-olefin monomer into a continuous reactor, and transporting the polyolefin to a batch reactor; and (S2) carrying out anionic polymerization of the polyolefin and styrene monomers in the batch reactor in the presence of an alkyllithium compound.

[0015] Advantageous Effects

[0016] The polyolefin-polystyrene multi-block copolymer of the present invention can be prepared in large quantities with excellent productivity by continuously polymerizing ethylene and α-olefin monomers to expand the polyolefin chain and then carrying out batch polymerization with styrene monomers. In addition, the manufacturing cost can be reduced compared with the conventional technology, thereby improving the economic feasibility and commercial practicability. Moreover, the polyolefin-polystyrene multi-block copolymer prepared thereby exhibits improved physical properties and can be usefully used in various industrial fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The stress-strain curves of the polyolefin-polystyrene multi-block copolymers according to Example 2-1 and Comparative Example 2-1 of the present invention are shown.

[0018] Figure 2 The stress-strain curves of the polyolefin-polystyrene multi-block copolymers according to Example 2-2 and Comparative Example 2-2 of the present invention are shown.

[0019] Figure 3 The stress-strain curves of the polyolefin-polystyrene multi-block copolymers according to Example 2-3 and Comparative Example 2-3 of the present invention are shown. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, the present invention will be described in more detail to help understand the present invention.

[0021] It should be understood that the words or terms used in the specification and claims of the present invention should not be construed as having the meanings defined in a common dictionary. It should be understood that the words or terms should be construed as having meanings consistent with their meanings in the technical concept of the present invention based on the principle that the inventor can appropriately define the meanings of the words to best explain the invention.

[0022] In the present invention, in the case of preparing a polyolefin-polystyrene multi-block copolymer by coordination polymerization of ethylene and α-olefin monomers and anionic polymerization with styrene monomers, in order to solve the problems of reduced productivity of the polyolefin block and deterioration of the physical properties of the polyolefin-polystyrene multi-block copolymer when carrying out coordination polymerization in a batch manner, the coordination polymerization of olefin monomers is carried out by continuous polymerization. In particular, olefin monomers are coordinatively polymerized in a continuous reactor to form a polyolefin block, and then the polyolefin block is transported to a batch reactor and anionic polymerization is carried out therein with styrene monomers.

[0023] In addition, in order to improve the efficiency of the continuous coordination polymerization reaction and further improve the physical properties of the finally prepared copolymer, the injection flow rates and the coordination polymerization time of the hafnium compound, the organic solvent, the ethylene gas and the α-olefin monomer entering the continuous reactor are controlled.

[0024] In particular, the method of the present invention includes: (S1) preparing a polyolefin by carrying out coordination polymerization of ethylene and an α-olefin monomer while continuously injecting a hafnium compound, an organozinc compound, an organic solvent, ethylene gas, and an α-olefin monomer into a continuous reactor, and transporting the polyolefin to a batch reactor; and (S2) carrying out anionic polymerization of the polyolefin and a styrene monomer in the batch reactor in the presence of an alkyllithium compound.

[0025] Through this preparation method, a target polyolefin chain can be formed from an olefin monomer by using an organozinc compound (chain transfer agent), and then, a polystyrene block can be formed at the end of the polyolefin chain by carrying out anionic polymerization with a styrene monomer, thereby preparing a polyolefin-polystyrene multi-block copolymer. In particular, by applying continuous polymerization and batch polymerization together, the realization of the thermoplastic elastomer properties of the copolymer can be further improved, and a copolymer having excellent physical properties (such as tensile properties) can be obtained.

[0026] Step (S1)

[0027] This is a step of preparing a polyolefin by carrying out coordination polymerization of ethylene and an α-olefin monomer while continuously injecting a hafnium compound, an organozinc compound, an organic solvent, ethylene gas, and an α-olefin monomer into a continuous reactor, and transporting the polyolefin to a batch reactor.

[0028] In this case, with respect to each 1 liter of the continuous reactor volume, the injection flow rate of the hafnium compound can be 0.16 μmol / min to 1.5 μmol / min, the injection flow rate of the organic solvent is 6 mL / min to 48 mL / min, the injection flow rate of ethylene gas under the conditions of 20 °C and 1 bar is 60 cc / min to 50000 cc / min, and the injection flow rate of the α-olefin monomer is 5 mL / min to 15 mL / min.

[0029] A continuous reactor refers to a reactor for continuously injecting raw materials for reaction, carrying out the reaction, and continuously discharging the product produced by polymerization. The continuous reactor can be, for example, a continuous stirred tank reactor (CSTR) (solution and slurry).

[0030] In the preparation method of the present invention, the coordination polymerization of olefin monomers is carried out in a continuous reactor (as a pre-step in the process of preparing polyolefin-polystyrene multi-block copolymers). Compared with the traditional method of carrying out the coordination polymerization of olefin monomers in a batchwise manner, excellent effects can be achieved in terms of the physical properties of the copolymer. In particular, in the case of first preparing polyolefin by polymerizing olefin monomers in a batchwise manner to prepare a multi-block copolymer, a semi-batch process can be carried out, which is a single-injection type in which all α-olefin monomers are injected at the starting point of the polymerization reaction. As the polymerization proceeds, the concentration of olefin monomers in the reactor may gradually decrease. Therefore, in the same polymer chain, the content of olefin monomers may gradually decrease over time, and there are problems that the chain arrangement may become non-uniform and the physical properties of the polymer may not be controllable. In addition, if the coordination polymerization of olefin monomers is carried out in a batchwise manner, it will be greatly affected by parameters including the injection point of the catalyst, the injection rate of olefin monomers, etc. The polymerization rate is fast and the calorific value is high. There are problems that the physical properties of polyolefin may be difficult to control, the reproducibility may be reduced, and large-scale production and commercial applications may be difficult.

[0031] On the contrary, in the preparation method of the present invention, the coordination polymerization is carried out in a continuous reactor. Thus, during the coordination polymerization reaction, the reaction mixture can be uniformly mixed, and the concentration of the monomer can be maintained at a constant level. Therefore, problems of changes in the physical properties of the polymer (including changes in the content of α-olefin monomers in the polyolefin chain) can be prevented. The arrangement of α-olefin monomers can become random to increase the attraction between polymer chains, and an improvement in the mechanical properties of the finally prepared copolymer can be expected.

[0032] In addition, regarding productivity, the preparation method of the present invention has advantages in large-scale production and commercial applications by carrying out the coordination polymerization in a continuous manner. In particular, in the case of batchwise polymerization, as the polymerization proceeds and with the repeated use of the initially injected catalyst, the activity may gradually decrease, and the efficiency of the polymerization reaction may decrease. On the contrary, in the case of continuous polymerization, new catalyst is continuously supplied as a reactant, showing a higher total catalyst activity for the coordination polymerization, and ethylene and α-olefin monomers can be polymerized efficiently.

[0033] In addition, during the polymerization of polyolefin-polystyrene multi-block copolymers through CCTP, the polymerization of ethylene and α-olefin monomers is initiated by a hafnium compound without a polymer chain and an organozinc compound itself. At the start of the reaction, the reaction is carried out in such a way that a polymer chain growing on the hafnium compound is unidirectionally provided to the organozinc compound, and after a certain time, effective CCTP can be carried out in a state where both the hafnium compound and the organozinc compound contain polymer chains. Therefore, there is a problem that an additional certain time is required before full CCTP. In addition, regarding the operation of the actual process, batch polymerization necessarily requires a cleaning time after one batch. As described above, in batch polymerization, due to various factors, the total time required for the process is increased compared to the time required for actual polymerization, which is a factor reducing productivity.

[0034] On the contrary, in the case of continuous polymerization, both the hafnium compound and the organozinc compound contain polymer chains after reaching a steady state, can carry out effective CCTP and show excellent productivity, and can operate the polymerization process without stopping and show high productivity.

[0035] In the present invention, the continuous reactor can be a single reactor or can refer to two or more continuous reactors arranged in series. In this case, the reactants can be injected into the first reactor of the reactors arranged in series and transported to the final reactor. After the polymerization is completed, the polyolefin can be discharged and transported to the batch reactor described later.

[0036] In the present invention, a hafnium compound can be used as long as the hafnium compound can form a polyolefin block through coordination polymerization with an olefin monomer, without limitation. Preferably, a homogeneous (metallocene) catalyst containing hafnium can be used, and more preferably, a hafnium pyridine amide catalyst can be used, without limitation.

[0037] By using the hafnium compound, an unnecessary β-elimination process can be prevented, a uniform polyolefin chain can be effectively extended by the organozinc compound to prepare high-molecular-weight polyolefins with various block compositions, and coordination chain transfer polymerization (CCTP) can be carried out.

[0038] The hafnium compound can be a compound activated by a cocatalyst compound. In this case, the cocatalyst compound can be a known compound in the art, for example, one or more selected from the following formulas 2 to 4.

[0039] [Formula 2]

[0040] –[Al(R a )-O] m -

[0041] [Formula 3]

[0042] D(Ra ) 3

[0043] [Formula 4]

[0044] [L-H] + [Z(A) 4 ) - or [L] + [Z(A) 4 ) -

[0045] In the above formulas,

[0046] each R a is independently: a halogen group; a hydrocarbon group having 1 to 20 carbon atoms; or a hydrocarbon group having 1 to 20 carbon atoms substituted with a halogen,

[0047] m is an integer of 2 or more,

[0048] D is aluminum or boron,

[0049] L is a neutral or cationic Lewis acid,

[0050] Z is an element of Group 13,

[0051] each A is independently: an aryl group having 6 to 20 carbon atoms in which one or more hydrogen atoms may be substituted by substituents; or an alkyl group having 1 to 20 carbon atoms,

[0052] The substituents of A are: halogen; a hydrocarbon group having 1 to 20 carbon atoms; an alkoxy group having 1 to 20 carbon atoms; or an aryloxy group having 6 to 20 carbon atoms.

[0053] The compound represented by Formula 2 is not particularly limited as long as it is an alkylaluminoxane. Preferred embodiments include methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, butylaluminoxane, etc., and a particularly preferred compound is methylaluminoxane.

[0054] The compound represented by Formula 3 is not particularly limited, but preferred embodiments include trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylchloroaluminum, triisopropylaluminum, di-sec-butylaluminum, tricyclopentylaluminum, tripentylaluminum, triisopentylaluminum, trihexylaluminum, trioctylaluminum, ethyldimethylaluminum, methyldiethylaluminum, triphenylaluminum, tri-p-tolylaluminum, dimethylmethanolaluminum, dimethylethanolaluminum, trimethylboron, triethylboron, triisobutylboron, tripropylboron, tributylboron, etc., and particularly preferred compounds are selected from trimethylaluminum, triethylaluminum, and triisobutylaluminum.

[0055] Examples of the compound represented by Formula 4 include bis(octadecyl)methylammonium tetrakis(pentafluorophenyl)borate [(C 18 H 37 )2 N(H)Me] + [B(C 6 F 5 ) 4 - , triethylammonium tetraphenylborate, tributylammonium tetraphenylborate, trimethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, trimethylammonium tetrakis(p-tolyl)borate, trimethylammonium tetrakis(o,p-dimethylphenyl)borate, tributylammonium tetrakis(p-trifluoromethylphenyl)borate, trimethylammonium tetrakis(p-trifluoromethylphenyl)borate, tributylammonium tetrakis(pentafluorophenyl)borate, N,N-diethylaniline tetrapentylborate, N,N-diethylaniline tetraphenylborate, N,N-diethylaniline tetrakis(pentafluorophenyl)borate, diethylaniline tetrakis(pentafluorophenyl)borate, triphenylphosphonium tetraphenylborate, trimethylphosphonium tetraphenylborate, triethylammonium tetraphenylaluminate, tributylammonium tetraphenylaluminate, trimethylammonium tetraphenylaluminate, tripropylammonium tetraphenylaluminate, trimethylammonium tetrakis(p-tolyl)aluminate, tripropylammonium tetrakis(p-tolyl)aluminate, triethylammonium tetrakis(o,p-dimethylphenyl)aluminate, tributylammonium tetrakis(p-trifluoromethylphenyl)aluminate, trimethylammonium tetrakis(p-trifluoromethylphenyl)aluminate, tributylammonium tetrakis(pentafluorophenyl)aluminate, N,N-diethylaniline tetraphenylaluminate, N,N-diethylaniline tetraphenylaluminate, N,N-diethylaniline tetrakis(pentafluorophenyl)aluminate, diethylammonium tetrakis(pentafluorophenyl)aluminate, triphenylphosphonium tetraphenylaluminate, trimethylphosphonium tetraphenylaluminate, triethylammonium tetraphenylaluminate, tributylammonium tetraphenylaluminate, trimethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, trimethylammonium tetrakis(p-tolyl)borate, tripropylammonium tetrakis(p-tolyl)borate, triethylammonium tetrakis(o,p-dimethylphenyl)borate, trimethylammonium tetrakis(o,p-dimethylphenyl)borate, tributylammonium tetrakis(p-trifluoromethylphenyl)borate, trimethylammonium tetrakis(p-trifluoromethylphenyl)borate, tributylammonium tetrakis(pentafluorophenyl)borate, N,N-diethylaniline tetraphenylborate, N,N-diethylaniline tetraphenylborate, N,N-diethylaniline tetrakis(pentafluorophenyl)borate, diethylammonium tetrakis(pentafluorophenyl)borate, triphenylphosphonium tetraphenylborate, triphenylcarbenium tetrakis(p-trifluoromethylphenyl)borate, triphenylcarbenium tetrakis(pentafluorophenyl)borate, etc.

[0056] The hafnium compound can be injected into the continuous reactor at a rate of 0.16 μmol / min to 1.5 μmol / min per 1 L of the continuous reactor volume. If the hafnium compound is injected within this range, the reactivity of the coordination polymerization reaction and the control of the reaction heat can be properly coordinated. At the same time, the extension and uniformity of the copolymer chain can be ensured, a copolymer with a narrow molecular weight distribution can be obtained, and the reproducibility of the reaction can be achieved. In addition, the advantages of suppressing the generation of ultra-high molecular weight and preventing fouling in the reactor can be expected. ​

[0057] The organozinc compound is used as a chain transfer agent, and is a material for inducing the preparation of a copolymer by chain transfer during the preparation of a polymerization reaction. In particular, it may be a compound represented by the following formula 1.

[0058] [Formula 1]

[0059]

[0060] In formula 1,

[0061] A is: an alkylene group having 1 to 20 carbon atoms; an arylene group having 6 to 20 carbon atoms; or an arylene group having 6 to 20 carbon atoms substituted with a halogen, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and

[0062] B is an arylene group having 6 to 12 carbon atoms substituted with an alkenyl group having 2 to 12 carbon atoms.

[0063] In addition, A may be: an alkylene group having 1 to 12 carbon atoms; an arylene group having 6 to 12 carbon atoms; or an arylene group having 6 to 12 carbon atoms substituted with a halogen, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and

[0064] B may be an arylene group having 6 to 12 carbon atoms substituted with an alkenyl group having 2 to 8 carbon atoms.

[0065] Formula 1 may have a structure in which both ends of the formula have double bonds. For example, if B is an aryl group substituted with an alkenyl group, the aryl group may be connected to A, and the double bond of the alkenyl group substituted on the aryl group may be located in the outermost layer in formula 4.

[0066] When the organozinc compound reacts with one or more olefin monomers in the presence of a catalyst composition, polymerization can occur while the olefin monomer is inserted between the zinc (Zn) and the organic group (A) of the organozinc compound.

[0067] Based on 1 equivalent of the hafnium compound, the amount of the organozinc compound used may be 1 to 200 equivalents. In particular, based on 1 equivalent of the hafnium compound, its amount used may be 10 to 100 equivalents.

[0068] The organozinc compound does not contain impurities such as THF and a large amount of magnesium salts and can be provided in high purity. Therefore, it can be used as a chain transfer agent and is advantageously used in olefin polymerization.

[0069] In addition, the Zn / Hf value, which is the molar ratio of hafnium element in the hafnium compound to zinc element in the organozinc compound, can be 1 or more, particularly 100 or more, and 200 or less, or 150 or less. If the Zn / Hf value is 1 or more and 200 or less, the amount of the chain transfer agent is appropriate compared to the hafnium compound, overuse of Zn can be prevented to improve economic feasibility, CCTP can be effectively carried out, and a reduction in the molecular weight distribution of the copolymer can be expected.

[0070] An organic solvent is injected to carry out the coordination polymerization of ethylene and α-olefin monomers in a homogeneous solution state, and a hydrocarbon solvent can be used. As the hydrocarbon solvent, an aliphatic hydrocarbon solvent having 4 to 20 carbon atoms can be used, for example, isobutane, hexane, cyclohexane, methylcyclohexane, or a mixture thereof, but is not limited thereto.

[0071] The organic solvent can be injected into the continuous reactor at a rate of 6 mL / min to 48 mL / min per 1 L of the continuous reactor volume. If the injection flow rate is 6 mL / min or more and 48 mL / min or less, the resulting copolymer can be sufficiently dissolved, the heat removal effect can be very good, and the residence time can be ensured to ensure sufficient growth of the copolymer.

[0072] In the present invention, ethylene and α-olefin monomers can be included as reactants for the coordination polymerization. In this case, ethylene can be injected as a gas.

[0073] The α-olefin monomers can specifically be aliphatic olefins having 3 to 20 carbon atoms, more specifically aliphatic olefins having 4 to 12 carbon atoms, and more specifically aliphatic olefins having 5 to 12 carbon atoms. As the aliphatic olefins, for example, propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-eicosene, 4,4-dimethyl-1-pentene, 4,4-diethyl-1-hexene, 3,4-dimethyl-1-hexene, etc. can be used, and any one of them or a mixture of two or more thereof can be used.

[0074] Ethylene gas can be injected at a rate of 60 cc / min to 50,000 cc / min per 1 L of the continuous reactor volume under the conditions of 20 °C and 1 bar.

[0075] In addition, the α-olefin monomers can be injected at a rate of 5 mL / min to 15 mL / min per 1 L of the continuous reactor volume.

[0076] If the injection flow rate of the α-olefin monomer is controlled within the above range, the concentration of the α-olefin monomer in the reactor is sufficient, the amount of insertion in the polymer chain can be very good, and the problem of inhibiting polymer expansion due to the reduction of the residence time can be prevented. In addition, if the flow rate of the α-olefin monomer and the flow rate of the organic solvent are controlled simultaneously, the concentration of the α-olefin monomer in the reactor can be maintained at an appropriate level, polyolefins having a preferred composition can be obtained, the removal of the reaction heat can be effectively achieved, and the polymerization can be carried out stably.

[0077] In coordination polymerization, the residence time of ethylene and the α-olefin monomer can be within 5 minutes to 2 hours. In particular, it is more than 18 minutes, more than 20 minutes, and less than 24 minutes, less than 22 minutes. By adopting an appropriate residence time within the above range, the time for sufficiently dissolving the olefin monomer can be ensured, and the reactants can be increased to an ultra-high viscosity, thereby playing a role in improving the productivity and producing polyolefins having excellent physical properties.

[0078] The temperature of the coordination polymerization can be changed according to the reaction substances and reaction conditions, but it can be 70 °C or higher, 90 °C or higher, 110 °C or higher, and 170 °C or lower, 130 °C or lower, 120 °C or lower. Within the above range, the catalyst can be thermally stable while increasing the solubility of the polymer.

[0079] After the polyolefin thus prepared is fed into the batch reactor, the polyolefin can act as a precursor for preparing polyolefin-polystyrene multi-block copolymers by the anionic polymerization reaction described below.

[0080] Step (S2)

[0081] This step is used to carry out the anionic polymerization of the polyolefin and the styrene monomer in the batch reactor in the presence of an alkyllithium compound, and the polyolefin-polystyrene multi-block can be formed by the anionic polymerization of the polyolefin chain formed in step (S1) and the styrene monomer carried out intermittently.

[0082] In particular, the styrene monomer can be continuously inserted between the zinc-carbon bonds of (polyolefin-based) contained in the compound formed in step (S1). 2 At the same time, the styrene group present at the end of the compound formed in step (S1) can participate as a copolymerization part with the styrene monomer, and thus be connected to the polystyrene chain. In addition, the multi-block copolymer formed by this method can be easily quenched by the reaction of the end group with water, oxygen or organic acid, and thus be converted into an industrially useful polyolefin-polystyrene multi-block copolymer.

[0083] Different from the continuous step (S1), step (S2) is carried out intermittently. In the case of anionic polymerization, controlling the block size is a key point in the process of synthesizing multi-block copolymers. Anionic polymerization proceeds through living polymerization. Therefore, the polymerization is carried out until all styrenic monomers are consumed. Thus, the decrease in the reactant concentration generated during intermittent polymerization may not affect the control of the block size. The polymerization can be carried out until the polymerization conversion rate reaches a maximum of 100%, and by controlling the injection amount of styrenic monomers, the block size can be controlled.

[0084] On the contrary, if the anionic polymerization in step (S2) is carried out continuously, the polymerization conversion rate may not increase to a maximum of 100% as in the anionic polymerization of intermittent polymerization. There is a residence time distribution, and it is difficult to control the block size by the injection amount of monomers. Therefore, there is a defect that it is difficult to control the copolymer block size. In addition, since an additional initiation time for using an anionic polymerization initiator is consumed in anionic polymerization, and if it is operated continuously, an additional residence time needs to be ensured to initiate the polymerization reaction uniformly at all reaction sites.

[0085] An important feature of anionic polymerization is to control the polymer molecular weight distribution to be narrow, which can be achieved by an intermittent reactor without residence time distribution. On the contrary, if a continuous reactor is used, the product has an inherent residence time distribution, which will increase the polymer molecular weight distribution, thus having an adverse effect on the physical properties of the polymer. At the same time, in order to improve the polymer productivity in a commercial reactor, anionic polymerization is sometimes carried out in a continuous reactor, but if the residence time is not long, the application is extremely limited. In the method for preparing a polyolefin-polystyrene multi-block copolymer of the present invention, anionic polymerization may require a long polymerization time. If a continuous reactor is used, there may be defects such as significantly increasing the reactor volume or increasing the number of reactors to meet the long residence time.

[0086] Considering these key points, in the present invention, in the case of preparing a polyolefin-polystyrene multi-block copolymer by carrying out coordination polymerization of ethylene and α-olefin monomers and then carrying out anionic polymerization of styrenic monomers using CCTP, the coordination polymerization is carried out continuously and the anionic polymerization is carried out intermittently, so as to achieve both the control of the physical properties of the copolymer and the improvement of the productivity.

[0087] In the present invention, the batch reactor in step (S2) can be connected in parallel with one of the continuous reactors in step (S1). After continuous polymerization by continuously injecting reactants for continuous coordination polymerization, in order to transfer the resulting product to the batch reactor and proceed to the next step, the injection port of the batch reactor is blocked to prevent the continuous transfer of polyolefin from the continuous reactor. In this case, since polyolefin is continuously produced in the continuous reactor, the waste of polyolefin can be prevented by transferring the polyolefin to another batch reactor.

[0088] Alkyllithium compounds are materials widely used as initiators for anionic polymerization. Triamine compounds have excellent coordination ability with lithium and can be used to improve the reactivity in the case of the reaction of alkyllithium compounds as bases or nucleophiles.

[0089] That is, in the present invention, alkyllithium compounds can be used as initiators through complexation with triamine compounds. In this way, the production of polyolefin-polystyrene multi-block copolymers, which is the target of the present invention, can be maximized, while suppressing the production amounts of polystyrene homopolymers, polyolefin homopolymers, and polyolefin-polystyrene diblock copolymers that may be produced using conventional initiators.

[0090] The alkyllithium compound can be represented by the following formula 5.

[0091] [Formula 5]

[0092]

[0093] In formula 5,

[0094] R 1 is a hydrocarbon group having 1 to 20 carbon atoms,

[0095] A is represented by the following formula 6.

[0096] [Formula 6]

[0097]

[0098] In formula 6,

[0099] R 2 to R 6 each independently is a hydrocarbon group having 1 to 20 carbon atoms,

[0100] a and b each independently are integers from 0 to 3.

[0101] R 1 can be hydrogen, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms with or without substituents;

[0102] R2 to R 6 may each independently be an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms with or without substituents, or an aralkyl group having 7 to 20 carbon atoms with or without substituents;

[0103] a and b are each independently an integer from 0 to 2.

[0104] R 1 to R 6 may each independently be: hydrogen or an alkyl group having 1 to 20 carbon atoms; a may be 1 or 2, and b may be 0 or 1.

[0105] a and b cannot be 0 at the same time. In particular, a may be an integer from 1 to 3, b may be an integer from 0 to 3. More particularly, a may be 1 or 2, b may be an integer from 0 to 2. More particularly, a may be 1 or 2, and b may be 0 or 1.

[0106] In Formula 5, A may specifically be represented by Formula 6a or Formula 6b below.

[0107] [Formula 6a]

[0108]

[0109] [Formula 6b]

[0110]

[0111] In the above formula,

[0112] R 2 、R 3 and R 6 are each independently hydrogen or an alkyl group having 1 to 20 carbon atoms.

[0113] In addition, in an embodiment of the present invention, A in Formula 1 may specifically be represented by Formula 6a-1 or 6b-1 below.

[0114] [Formula 6a-1]

[0115]

[0116] [Formula 6b-1]

[0117]

[0118] The anionic polymerization initiator according to an embodiment of the present invention is an anionic polymerization agent for polymerizing the polystyrene block of a polyolefin-polystyrene block copolymer, and can be used by reacting with a polyolefin zinc compound (e.g., (polyolefin group) 2An anionic polymerization initiator for forming a polyolefin-polystyrene block copolymer by reacting with Zn).

[0119] (Polyolefin-based) 2 Zn is prepared by coordination chain transfer polymerization (CCTP), and the additional extension of the polymer chain starting from (polyolefin-based) 2 Zn can be effectively used for synthesizing polyolefin (PO) block copolymers. For example, PO functionalized with -OH end groups was used to attempt to synthesize polyethylene-block-polyester and polyethylene-block-polyether, which can be achieved by treating the CCTP product (polyolefin-based) 2 with Zn to generate. In the same way, a polystyrene (PS) block can be synthesized from (polyolefin-based) 2 Zn by a one-pot method, polyethylene-block-polystyrene block copolymer can be prepared, and by polymerizing styrene monomers in the presence of (polyolefin-based) 2 Zn using the anionic polymerization initiator of the present invention, the PS chain can be effectively extended from (polyolefin-based) 2 Zn. 2

[0120] In addition, the present invention provides an anionic polymerization initiator composition comprising a compound represented by Formula 6 and a compound represented by Formula 7.

[0121] [Formula 6]

[0122]

[0123] [Formula 7]

[0124] B-Li

[0125] In Formula 6,

[0126] R 2 to R 6 are each independently a hydrocarbon group having 1 to 20 carbon atoms,

[0127] a and b are each independently an integer from 0 to 3,

[0128] In Formula 7,

[0129] B is an alkyl group having 1 to 20 carbon atoms.

[0130] In an embodiment of the present invention, R 2 to R 6 can each independently be an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms with or without substituents, or an aralkyl group having 7 to 20 carbon atoms with or without substituents; ​

[0131] B can be an alkyl group having 1 to 12 carbon atoms;

[0132] a and b can each independently be an integer from 0 to 2.

[0133] In addition, in an embodiment of the present invention, R 2 to R 6 can each independently be hydrogen or an alkyl group having 1 to 20 carbon atoms; B can be an alkyl group having 1 to 8 carbon atoms; a can be an integer of 1 or 2, and b can be an integer of 0 or 1.

[0134] a and b cannot be 0 at the same time. In particular, a can be an integer from 1 to 3, b can be an integer from 0 to 3. More particularly, a can be 1 or 2, b can be an integer from 0 to 2. More particularly, a can be 1 or 2, b can be 0 or 1.

[0135] In an embodiment of the present invention, the anionic polymerization initiator composition may further contain a compound represented by the following formula 8.

[0136] [Formula 8]

[0137]

[0138] R 1 is a hydrocarbon group having 1 to 20 carbon atoms.

[0139] The anionic polymerization initiator composition may not contain additional compounds that can be used as solvents other than the compounds represented by formula 6, the compounds represented by formula 7, and other compounds represented by formula 8, or may contain a small amount, and significant reaction with the compound of formula 7 is not allowed.

[0140] If the anionic polymerization initiator composition containing the compound represented by formula 6 and the compound represented by formula 7 is injected as an anionic polymerization initiator, a structure similar to formula 5 can be formed, which can be used as an anionic polymerization initiator.

[0141] In addition, the anionic polymerization initiator of the present invention includes a reaction process of injecting the compound represented by the following formula 6 and the compound represented by the following formula 7 in the presence of the compound represented by the following formula 8.

[0142] [Formula 6]

[0143]

[0144] [Formula 7]

[0145] B-Li

[0146] [Formula 8]

[0147]

[0148] In the above formula,

[0149] R 1 to R 6 are each independently a hydrocarbon group having 1 to 20 carbon atoms;

[0150] a and b are each independently an integer from 0 to 3;

[0151] B is an alkyl group having 1 to 20 carbon atoms.

[0152] In an embodiment of the present invention, R 2 to R 6 may each independently be an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms with or without substituents, or an aralkyl group having 7 to 20 carbon atoms with or without substituents; a and b may each independently be an integer from 0 to 2; B may be an alkyl group having 1 to 12 carbon atoms.

[0153] Further, in an embodiment of the present invention, R 2 to R 6 may each independently be hydrogen or an alkyl group having 1 to 20 carbon atoms; a may be an integer of 1 or 2, b may be an integer of 0 or 1; B may be an alkyl group having 1 to 8 carbon atoms.

[0154] a and b cannot both be 0 at the same time. In particular, a may be an integer from 1 to 3, b may be an integer from 0 to 3. More particularly, a may be 1 or 2, b may be an integer from 0 to 2. More particularly, a may be 1 or 2, b may be 0 or 1.

[0155] The alkyllithium compound represented by Formula 7 may be, for example, n-BuLi, which is a material widely used as an anionic polymerization initiator, is easily obtainable, and has excellent unit price efficiency.

[0156] In the method for preparing an anionic polymerization initiator according to an embodiment of the present invention, the process of reacting the compound represented by Formula 8 and the compound represented by Formula 7 may be first carried out, and then, by reacting the compound represented by Formula 6, the compound represented by Formula 5 may be prepared. In particular, by reacting the compound represented by Formula 8 with the compound represented by Formula 7, allyllithium is generated as an intermediate, and allyllithium reacts with the compound represented by Formula 6 to finally form the anionic polymerization initiator of Formula 5.

[0157] In addition, in the method for preparing an anionic polymerization initiator according to an embodiment of the present invention, the process of injecting the compound represented by Formula 7 and the compound represented by Formula 6 to react in the presence of the compound represented by Formula 8 can be carried out under the condition of no additional solvent. The condition of no additional solvent means that in the presence of the compound represented by Formula 8, except for the compound represented by Formula 7 and the compound represented by Formula 6, there is no other compound that can be a solvent, or a small amount is present and does not allow a significant reaction with the compound of Formula 7.

[0158] If the reaction is carried out under the condition of no additional solvent, the reaction between the compound represented by Formula 8 and the compound represented by Formula 7 can proceed as the main reaction, and the anionic polymerization initiator of Formula 5 can be effectively prepared. If there is a separate solvent, the anionic polymerization initiator of Formula 5, the compound formed by the reaction of the compound represented by Formula 7 and the compound represented by Formula 6, and the decomposition compound of the compound formed by the reaction of the compound represented by Formula 7 and the compound represented by Formula 6 may exist in a mixed state, which is ineffective.

[0159] The anionic polymerization initiator or anionic polymerization initiator composition of the present invention can be used as an initiator for polymerizing styrene and can be effectively used as an initiator for extending a polystyrene chain from an organozinc compound, particularly (polyolefin-based) 2 Zn (extending a polyolefin chain with zinc (Zn) as the center) to extend a polystyrene chain.

[0160] The styrene monomer can be a styrene monomer having 6 to 20 carbon atoms, and more particularly, a styrene monomer including ethylene substituted with an aryl group having 6 to 20 carbon atoms or ethylene substituted with a phenyl group, such as styrene, α-methylstyrene, α-ethylstyrene, p-methylstyrene, or a mixture thereof.

[0161] In particular, an alkyllithium compound and a triamine compound can be mixed with an aliphatic hydrocarbon solvent and injected, or injected sequentially into a batch reactor.

[0162] The temperature of anionic polymerization can be changed according to the reactants, reaction conditions, etc., and can be particularly 40 °C or higher, 90 °C or higher, and 170 °C or lower, 120 °C or lower.

[0163] The time of anionic polymerization can be changed according to the reactants, reaction conditions, etc., and can be particularly 0.5 hour to 10 hours, 0.5 hour to 8 hours, 0.5 hour to 5 hours, or 0.5 hour to 2 hours. Within this range, it is advantageous to convert all the injected styrene monomers into a multi-block copolymer.

[0164] Through this reaction, polyolefin-polystyrene multi-block copolymers can be prepared, and they can be, for example, polystyrene-poly(ethylene-co-propylene)-polystyrene block copolymers, polystyrene-poly(ethylene-co-1-butene)-polystyrene block copolymers, polystyrene-poly(ethylene-co-1-pentene)-polystyrene block copolymers, polystyrene-poly(ethylene-co-1-hexene)-polystyrene block copolymers, polystyrene-poly(ethylene-co-1-heptene)-polystyrene block copolymers, polystyrene-poly(ethylene-co-1-octene)-polystyrene block copolymers, or mixtures thereof.

[0165] Example

[0166] Hereinafter, the present invention will be explained in more detail with reference to the embodiments. However, the embodiments are used to illustrate the present invention, and the scope of the present invention is not limited thereto.

[0167] 1. Preparation of polyolefin

[0168] Example 1-1

[0169] In a 0.3 L continuous stirred tank reactor, while injecting 0.17 mL / min (0.15 μmol / min) of a hafnium compound activated with [(C 18 H 37 ) 2 N(H)Me] + [B(C 6 F 5 ) 4 - (45.0 μmol), 0.17 mL / min (23 μmol / min) of an organozinc compound as a chain transfer agent, 6 mL / min of methylcyclohexane (MCH) as an organic solvent, 1500 cc / min of ethylene gas, and 2.7 mL / min of 1-hexene as an α-olefin monomer, the pressure and temperature in the reactor were set to 25 bar and 90 °C, and polymerization was carried out with a residence time of 24 minutes to prepare a polyolefin.

[0170] Examples 1-2 to 1-13

[0171] Preparation was carried out in the same manner as in Example 1-1, except that the polymerization conditions in the continuous reactor were changed as shown in Table 1 below.

[0172] [Table 1]

[0173]

[0174] Comparative Example 1-1

[0175] ​In a batch reactor, both coordination polymerization and anionic polymerization are carried out to prepare polyolefin-polystyrene copolymers. Specifically, a parr reactor (1 gallon) is dried under vacuum at 120 °C for 2 hours. Oc 3 A solution of Al (1466.4 mg, 1000 μmol - Al) in methylcyclohexane (1200 g) is added to the reactor. The mixture is stirred at 120 °C for 1 hour using a heating jacket, and then the solution is removed using a cannula.

[0176] A solution containing Oc 3 Al (1098.3 mg, 749 μmol - Al / 25 wt%, in hexane) in methylcyclohexane (1170 mL) is charged into the reactor as a scavenger, and 1 - hexene (639 mL) is charged as an α - olefin monomer, with the temperature set at 90 °C. A solution of an organozinc compound (1000 μmol) in methylcyclohexane (3.85 g) is charged as a chain transfer agent, and then a solution of an activated hafnium compound (10.0 μmol - Hf) (10.0 μmol) in methylcyclohexane (1.68 g) containing [[(C 18 H 37 ) 2 N(H)Me] + [B(C 6 F 5 ) 4 - is injected. The pressure in the reactor is maintained at 25 bar by opening the valve of the ethylene tank, and polymerization is carried out for 40 minutes to prepare polyolefin.

[0177] Comparative Examples 1 - 2 and 1 - 3

[0178] Preparation is carried out in the same manner as Comparative Example 1 - 1, except that the polymerization conditions in the batch reactor are changed as shown in Table 2 below.

[0179] [Table 2]

[0180]

[0181] In the table, the volume of ethylene is based on 20 °C and 1 atm.

[0182] 2. Preparation of polyolefin-polystyrene multi-block copolymer

[0183] Example 2 - 1

[0184] In a batch reactor, anionic polymerization is carried out on a styrene monomer and the polyolefin prepared in Example 1 - 8 as a reactant.

[0185] ​The resulting product comprising the polyolefin prepared in Examples 1 to 8 was transferred to a batch reactor, and a mixture prepared by mixing Me in methylcyclohexane (3.85 g) was injected thereinto. 3 SiC 2 Me 3 SiC 2 Li(PMDETA) solution. After maintaining the temperature at 90°C for 30 minutes with stirring, styrene (7.8 g) was injected. The temperature was controlled in the range of 90°C to 100°C using a heating mantle.

[0186] The viscosity gradually increases and becomes almost invisible within 5 hours. 1 H NMR analysis confirmed that styrene was completely converted. After styrene was completely converted, 2-ethylhexanoic acid and ethanol were continuously injected. The obtained polymer block (23 g) was dried in a vacuum oven at 80°C overnight.

[0187] Examples 2-2 and 2-3

[0188] A polyolefin-polystyrene-based multi-block copolymer was prepared in the same manner as in Example 2-1, except that Examples 1-11 and 1-12 were used, respectively, instead of the polyolefin of Example 1-8 in Example 2-1.

[0189] Comparative Example 2-1

[0190] In a batch reactor, anionic polymerization was carried out using a styrene-based monomer and the polyolefin prepared in Comparative Example 1-1 as reactants.

[0191] In the reactor containing the polyolefin prepared in Comparative Example 1-1, the temperature was controlled in the range of 90°C to 120°C, and the remaining ethylene gas was discharged. If the temperature reached 90°C, a mixture of Me and 1.5 g of ethylene was added. 3 SiC 2 Me 3 SiC 2 Li(PMDETA) solution. After maintaining the temperature at 90°C for 30 minutes with stirring, styrene (69.0 g) was injected. The temperature was controlled in the range of 90°C to 100°C using a heating mantle.

[0192] The viscosity gradually increases and becomes almost invisible within 5 hours. 11H NMR analysis was performed to confirm the complete conversion of styrene. After the complete conversion of styrene, 2-ethylhexanoic acid and ethanol were continuously injected. The obtained polymer block (132 g) was dried overnight in a vacuum oven at 80 °C.

[0193] Comparative Example 2-2 and 2-3

[0194] A polyolefin-polystyrene multi-block copolymer was prepared in the same manner as in Comparative Example 2-1, except that Comparative Example 2-2 and Comparative Example 2-3 were respectively applied instead of the polyolefin of Comparative Example 1-1 used in Comparative Example 2-1.

[0195] Experimental Example 1: Analysis of polyolefin

[0196] (1) Measurement of the contents of ethylene and α-olefin

[0197] The measurement was carried out by NMR. Under the conditions of ns = 16, d1 = 3 s, solvent = TCE-d2 and 373 K, a Bruker 600 MHz AVANCE III HD NMR instrument was used for measurement. 1 1H NMR, the solvent peak of TCE-d2 was calibrated to 6.0 ppm. The CH of 1-propene 3 It was confirmed at 1 ppm that the CH of the butyl side chain was through 1-hexene. 3 The relevant peak (triplet) was confirmed at about 0.96 ppm and the content was calculated. In addition, the styrene content was calculated from the aromatic peaks around 6.5 ppm to 7.5 ppm.

[0198] (2) Weight-average molecular weight (Mw, g / mol) and molecular weight distribution (polydispersity index, PDI)

[0199] The weight-average molecular weight (Mw, g / mol) and number-average molecular weight (Mn, g / mol) were respectively measured using gel permeation chromatography (GPC), and the molecular weight distribution (polydispersity index, PDI) was calculated by dividing the weight-average molecular weight by the number-average molecular weight.

[0200] - Column: PL Olexis

[0201] - Solvent: trichlorobenzene (TCB)

[0202] - Flow rate: 1.0 mL / min

[0203] - Sample concentration: 1.0 mg / mL

[0204] - Injection volume: 200 μL

[0205] - Column temperature: 160 °C

[0206] - Detector: Agilent high-temperature RI detector

[0207] - Standard: polystyrene

[0208] - Calculate the molecular weight by universal calibration using the Mark Houwink equation (K = 40.8×10 -5 , α = 0.7057).

[0209] (3) Polyolefin yield (tons / m 3 hrmol)

[0210] In the case of Examples 1-1 to 1-13, the amount of polyolefin discharged from the continuous reactor through the total reaction was measured, and the mass relative to volume, time, and mole number was calculated. In the case of Comparative Examples 1-1 to 1-3, the degree of polyolefin yield was calculated by comparing the yield of the multiblock copolymer prepared in Comparative Examples 2-1 to 2-3 and the mass fractions of C2 and 1-C6 measured by 1 1H NMR.

[0211] [Table 3]

[0212]

[0213] In the case of Comparative Example 1-1, ethylene and α-olefin monomers were subjected to coordination polymerization in a batch reactor, and the polyolefin yield was 5,086 tons / m 3 ·hr·mol, which was significantly lower compared to the Examples and Comparative Examples of coordination polymerization by continuous reaction. At the same time, in the case of Example 1-13, by changing specific conditions including the solvent injection amount, etc. in the reaction conditions, results were obtained. It can be confirmed from the data that the polyolefin has a low molecular weight and a wide molecular weight distribution, but the production amount is significantly excellent compared to Comparative Examples 1-1 to 1-3.

[0214] Experimental Example 2: Analysis of polyolefin-polystyrene multi-block copolymer

[0215] For the polyolefin-polystyrene multiblock copolymers prepared in the Examples and Comparative Examples, the physical properties were measured according to the following conditions and methods, and the results are shown in Tables 4 to 6.

[0216] (1) Measurement of the contents of ethylene, α-olefin and styrene

[0217] Measurement was carried out in the same manner as in Experimental Example 1. The content of styrene was calculated using the aromatic peak around 6.5 ppm to 7.5 ppm.

[0218] (2) Weight-average molecular weight (Mw, g / mol) and molecular weight distribution (polydispersity index, PDI)

[0219] Measurement was carried out in the same manner as in Experimental Example 1.

[0220] (3) Tensile properties

[0221] Tensile test methods based on ASTM D412 were used to fabricate each specimen, and the tensile strength, elongation at break, and 300% modulus were measured. The stress-strain curves are as Figures 1 to 3 shown.

[0222] [Table 4]

[0223]

[0224] [Table 5]

[0225]

[0226] [Table 6]

[0227]

[0228] As shown in Tables 4 to 6, in the case of Comparative Examples 2-1 to 2-3 where all polymerization processes were carried out in a batch reactor, the tensile properties were lower than those of the corresponding Examples 2-1 to 2-3, respectively. The results may be negative evidence of the non-uniform arrangement of monomers in the polymer chain. Structurally, it is impossible to effectively induce the distribution of tensile properties in the polymer chain.

[0229] The differences in polymer physical properties with the polymerization process can be Figures 1 to 3 clearly confirmed. Referring to Figures 1 to 3 , it can be confirmed that compared with the polyolefin-polystyrene multi-block copolymers of Comparative Examples 2-1 to 2-3, the polyolefin-polystyrene multi-block copolymers of Examples 2-1 to 2-3 show very high tensile strength, and it can be confirmed that even when the styrene content is low as in Example 2-1, very high tensile strength is still shown. It is considered that this result is because even for polyolefins with similar molecular weights and compositions, if polymerization is carried out by continuous polymerization, the effect of monomer arrangement in the polymer chain can be maximized, and even better effects can be shown.

[0230] In addition, through Examples 2-1 to 2-3, it can be confirmed that the tensile strength and elongation at break can be controlled according to the control of the α-olefin and styrene contents.

Claims

1. A method for preparing a polyolefin-polystyrene multi-block copolymer, the method comprises: (S1) preparing a polyolefin by carrying out coordination polymerization of ethylene and an α-olefin monomer while continuously injecting a hafnium compound, an organozinc compound, an organic solvent, ethylene gas and an α-olefin monomer into a continuous reactor, and transporting the polyolefin to a batch reactor; and (S2) carrying out anionic polymerization of the polyolefin and a styrene monomer in the presence of an alkyllithium compound in the batch reactor, wherein, the injection flow rate of the organic solvent is 6 mL / min to 48 mL / min per 1 liter of the volume of the continuous reactor.

2. The method for preparing a polyolefin-polystyrene multi-block copolymer according to claim 1, wherein, the Zn / Hf value, which is the molar ratio of zinc element in the organozinc compound to hafnium element in the hafnium compound, is 1 or more.

3. The method for preparing a polyolefin-polystyrene multi-block copolymer according to claim 1, wherein, the organozinc compound is a compound represented by the following formula 1: [Formula 1] In formula 1, A is: an alkylene group having 1 to 20 carbon atoms; an arylene group having 6 to 20 carbon atoms; or an arylene group having 6 to 20 carbon atoms substituted with a halogen, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, an alkoxy group having 1 to 8 carbon atoms or an aryl group having 6 to 12 carbon atoms, and B is an arylene group having 6 to 12 carbon atoms substituted with an alkenyl group having 2 to 12 carbon atoms.

4. The method for preparing a polyolefin-polystyrene multi-block copolymer according to claim 1, wherein, the organic solvent is one or more selected from the group consisting of methylcyclohexane, isobutane, hexane and cyclohexane.

5. The method for preparing a polyolefin-polystyrene multi-block copolymer according to claim 1, wherein, the α-olefin monomer is one or more selected from the group consisting of propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-eicosene, 4,4-dimethyl-1-pentene, 4,4-diethyl-1-hexene and 3,4-dimethyl-1-hexene.

6. The method for preparing a polyolefin-polystyrene multi-block copolymer according to claim 1, wherein, the alkyllithium compound is a compound represented by the following formula 5: [Formula 5] In formula 5, R 1 is a hydrocarbon group having 1 to 20 carbon atoms, and A is represented by the following formula 6: [Formula 6] In formula 6, R 2 to R 6 each independently represents a hydrocarbon group having 1 to 20 carbon atoms, and a and b are each independently an integer from 0 to 3.

7. The method for preparing a polyolefin-polystyrene multi-block copolymer according to claim 1, wherein, the styrene monomer is one or more selected from the group consisting of styrene, α-methylstyrene, α-ethylstyrene and p-methylstyrene.

8. The method for preparing a polyolefin-polystyrene multi-block copolymer according to claim 1, wherein, the coordination polymerization is carried out at a temperature of 70 °C to 170 °C.

9. The method for preparing a polyolefin-polystyrene multi-block copolymer as claimed in claim 1, wherein, the anionic polymerization is carried out at a temperature of 40°C to 170°C for 0.5 hour to 10 hours.

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