Catalyst composition, method of preparing the composition, method of preparing conjugated diene-based polymer by using the composition, and conjugated diene-based polymer prepared by the method of preparing the polymer

Abstract

A catalyst composition capable of forming a conjugated diene-based polymer having a narrow molecular weight distribution by being used in polymerization of a conjugated diene-based monomer, a method of preparing the same, a method of preparing a conjugated diene-based polymer using the catalyst composition, and a conjugated diene-based polymer prepared by the method of preparing the polymer are provided. Since the catalyst composition according to the present invention includes a polymer having a number-average molecular weight of 3,000 g/mol to 10,000 g/mol and including a conjugated diene-based monomer-derived unit, the catalyst composition may be used in the polymerization of a conjugated diene-based monomer to prepare a conjugated diene-based polymer having a narrower molecular weight distribution in comparison to a conventional neodymium catalyst composition.

Claims

1. A catalyst composition comprising a polymer, wherein the polymer comprises: a neodymium compound-derived unit; an alkylating agent-derived unit; and a conjugated diene-based monomer-derived unit, and the polymer has a number-average molecular weight of 3,000 g/mol to 10,000 g/mol.

2. The catalyst composition of claim 1, wherein the catalyst composition comprises the polymer in an amount of 10 wt % or more to less than 60 wt %.

3. The catalyst composition of claim 1, wherein the polymer has a molecular weight distribution of 2.3 to 2.8.

4. The catalyst composition of claim 1, further comprising a halogenated reactant of the neodymium compound, the alkylating agent, the conjugated diene-based monomer, and a halide.

5. The catalyst composition of claim 1, wherein the neodymium compound is a compound represented by Formula 1: ##STR00004## wherein, R.sub.a to R.sub.c are each independently hydrogen or an alkyl group having 1 to 12 carbon atoms, provided that at least one of R.sub.a, R.sub.b or R.sub.c is not hydrogen.

6. The catalyst composition of claim 1, wherein the alkylating agent comprises an organoaluminum compound of Formula 2:
Al(R).sub.z(X).sub.3-z  [Formula 2] wherein, R is each independently a hydrocarbyl group having 1 to 30 carbon atoms, or a heterohydrocarbyl group having 1 to 30 carbon atoms which contains at least one heteroatom of a nitrogen atom, an oxygen atom, a boron atom, a silicon atom, a sulfur atom, or a phosphorus atom; X is each independently selected from the group consisting of a hydrogen atom, a halogen group, a carboxyl group, an alkoxy group having 1 to 20 carbon atoms, and an aryloxy group having 6 to 20 carbon atoms, and z is an integer of 1 to 3.

7. A method of preparing a neodymium-catalyzed conjugated diene-based polymer, comprising: polymerizing a third conjugated diene-based monomer in the presence of the catalyst composition of claim 1, wherein the catalyst composition comprises a polymer having a number-average molecular weight of 3,000 g/mol to 10,000 g/mol and including a neodymium compound-derived unit; an alkylating agent-derived unit; and a conjugated diene-based monomer-derived unit.

8. The method of claim 7, wherein, during the polymerization, the catalyst composition is in an amount such that neodymium in the catalyst composition is included in an amount of 0.03 mmol to 0.10 mmol based on 1 mol of the third conjugated diene-based monomer.

9. The method of claim 7, wherein the polymerization is performed in a temperature range of 50° C. to 200° C.

10. A method of preparing a catalyst composition, the method comprising: preparing a halogenated reactant by reacting a neodymium compound, an alkylating agent, a first conjugated diene-based monomer, and a halide in the presence of a hydrocarbon solvent; and reacting the halogenated reactant with a second conjugated diene-based monomer, wherein the second conjugated diene-based monomer is in an amount of 200 mol to 900 mol based on 1 mol of neodymium in the neodymium compound.

11. The method of claim 10, wherein the reacting the halogenated reactant with the second conjugated diene-based monomer is performed in a temperature range of −20° C. to 40° C. for 5 minutes to 3 hours.

12. The method of claim 10, wherein the neodymium compound, the alkylating agent, the halide, and the first conjugated diene-based monomer are in a molar ratio of 1:5 to 200:2 to 20:1 to 100.

Description

EXAMPLE 1

(1) After neodymium versatate (NdV, Nd(2-ethylhexanoate).sub.3) was added in a hexane solvent under a nitrogen condition and diisobutylaluminum hydride (DIBAH), diethylaluminum chloride (DEAC), and 1,3-butadiene were sequentially added such that a molar ratio of NdV:DIBAH:DEAC:1,3-butadiene was 1:10:3:30, mixing is performed at 20° C. for 12 hours to prepare a chlorination reactant (preforming catalyst composition). 200 mol of 1,3-butadiene (BD) based on 1 mol of neodymium (Nd) was slowly added thereto at 0° C. and stirred for 60 minutes to prepare a catalyst composition. The prepared catalyst composition was used after storage at 0° C. under a nitrogen condition for 24 hours.

EXAMPLE 2

(2) A catalyst composition was prepared in the same manner as in Example 1 except that 1,3-butadiene (BD) was slowly added to the chlorination reactant at 20° C. and stirred for 30 minutes in Example 1. The prepared catalyst composition was used after storage at 0° C. under a nitrogen condition for 24 hours.

EXAMPLE 3

(3) A catalyst composition was prepared in the same manner as in Example 1 except that 1,3-butadiene (BD) was slowly added to the chlorination reactant at 40° C. and stirred for 10 minutes in Example 1. The prepared catalyst composition was used after storage at 0° C. under a nitrogen condition for 24 hours.

EXAMPLE 4

(4) A catalyst composition was prepared in the same manner as in Example 1 except that 900 mol of 1,3-butadiene (BD) based on 1 mol of Nd was slowly added to the chlorination reactant at 0° C. and stirred for 60 minutes in Example 1. The prepared catalyst composition was used after storage at 0° C. under a nitrogen condition for 24 hours.

COMPARATIVE EXAMPLE 1

(5) After neodymium versatate (NdV, Nd(2-ethylhexanoate).sub.3) was added in a hexane solvent under a nitrogen condition and diisobutylaluminum hydride (DIBAH), diethylaluminum chloride (DEAC), and 1,3-butadiene were sequentially added such that a molar ratio of NdV:DIBAH:DEAC:1,3-butadiene was 1:9˜10:2˜3:30, mixing is performed at 20° C. for 12 hours to prepare a catalyst composition. The prepared catalyst composition was used after storage at 0° C. under a nitrogen condition for 24 hours.

COMPARATIVE EXAMPLE 2

(6) A catalyst composition was prepared in the same manner as in Example 1 except that 70 mol of 1,3-butadiene (BD) based on 1 mol of Nd was slowly added to the chlorination reactant at 0° C. and stirred for 60 minutes in Example 1. The prepared catalyst composition was used after storage at 0° C. under a nitrogen condition for 24 hours.

COMPARATIVE EXAMPLE 3

(7) A catalyst composition was prepared in the same manner as in Example 1 except that 1,800 mol of 1,3-butadiene (BD) based on 1 mol of Nd was slowly added to the chlorination reactant at 0° C. and stirred for 60 minutes in Example 1. The prepared catalyst composition was used after storage at 0° C. under a nitrogen condition for 24 hours.

EXPERIMENTAL EXAMPLE 1

(8) An amount of a polymer in each composition and a number-average molecular weight of the polymer were measured for each of the catalyst compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 3. The results thereof are presented in Table 1 below.

(9) 1) Amount of Polymer

(10) Each catalyst composition was added to isopropyl alcohol and stirred to collect precipitates and the precipitates were dried in a drying oven. A weight of a solid obtained by the drying was measured, and an amount of a polymer in the catalyst composition was calculated through the following Equation 1.
Polymer amount (wt %)={weight (g) of solid/weight (g) of catalyst composition}×100  [Equation 1]

(11) 2) Number-Average Molecular Weight and Molecular Weight Distribution of Polymer

(12) After each catalyst composition was dissolved in tetrahydrofuran (THF) at 40° C. for 30 minutes, a weight-average molecular weight and a number-average molecular weight were measured using gel permeation chromatography (GPC), and a molecular weight distribution was calculated as a ratio of the weight-average molecular weight to the number-average molecular weight. In this case, two PLgel Olexis (product name) columns by Polymer Laboratories and one PLgel mixed-C (product name) column by Polymer Laboratories were combined and used as a column, all newly replaced columns were mixed-bed type columns, and polystyrene was used as a GPC standard material.

(13) TABLE-US-00001 TABLE 1 Example Comparative Example Category 1 2 3 4 1 2 3 Amount (wt %) 18.5 20.1 21.0 53.3 — 9.2 86.5 Number-average 3,000 3,000 3,000 10,000 — 1,000 20,000 molecular weight (g/mol) Molecular 2.51 2.53 2.77 2.58 2.90 2.85 2.87 weight distribution

(14) From Table 1, it was confirmed that the polymers having a number-average molecular weight of 3,000 g/mol to 10,000 g/mol and a molecular weight distribution of 2.5 to 2.8 were present in the catalyst compositions of Examples 1 to 4.

EXAMPLE 5

(15) After alternatingly applying vacuum and nitrogen to a completely dried reactor, 4.2 kg of hexane and 500 g of 1,3-butadiene were added to the 15 L reactor in vacuum, temperature of the reactor was increased to 70° C. After the catalyst composition of Example 1 was added thereto, polymerization was performed for 60 minutes to prepare an active polymer. In this case, a conversion rate of the 1,3-butadiene into a polybutadiene polymer was 100%. Thereafter, a hexane solution including 1.0 g of a polymerization terminator and a hexane solution including 2.0 g of an antioxidant were added to terminate the reaction, and a butadiene polymer was prepared.

EXAMPLE 6

(16) A butadiene polymer was prepared in the same manner as in Example 5 except that, in Example 5, the catalyst composition of Example 2 was used instead of the catalyst composition of Example 1.

EXAMPLE 7

(17) A butadiene polymer was prepared in the same manner as in Example 5 except that, in Example 5, the catalyst composition of Example 3 was used instead of the catalyst composition of Example 1.

EXAMPLE 8

(18) A butadiene polymer was prepared in the same manner as in Example 5 except that, in Example 5, the catalyst composition of Example 4 was used instead of the catalyst composition of Example 1.

COMPARATIVE EXAMPLE 4

(19) A butadiene polymer was prepared in the same manner as in Example 5 except that, in Example 5, the catalyst composition of Comparative Example 1 was used instead of the catalyst composition of Example 1.

COMPARATIVE EXAMPLE 5

(20) A butadiene polymer was prepared in the same manner as in Example 5 except that, in Example 5, the catalyst composition of Comparative Example 2 was used instead of the catalyst composition of Example 1.

COMPARATIVE EXAMPLE 6

(21) A butadiene polymer was prepared in the same manner as in Example 5 except that, in Example 5, the catalyst composition of Comparative Example 3 was used instead of the catalyst composition of Example 1.

EXPERIMENTAL EXAMPLE 2

(22) Microstructural analysis, a number-average molecular weight (Mn), a weight-average molecular weight (Mw), a molecular weight distribution (MWD), Mooney viscosity (MV), and a −S/R value were measured for each of the polymers prepared in Examples 5 to 8 and Comparative Examples 4 to 6 by the following methods. The results thereof are presented in Table 2 below.

(23) 1) Microstructural Analysis

(24) Cis-1,4 bond content, trans-1,4 bond content, and vinyl-1,2 bond content of a conjugated diene portion were measured by Fourier transform infrared spectroscopy (FT-IR).

(25) Specifically, after measuring a FT-IR transmittance spectrum of a carbon disulfide solution of the conjugated diene-based polymer which is prepared at a concentration of 5 mg/mL by using disulfide carbon of the same cell as a blank, each content was obtained by using a maximum peak value (a, base line) near 1,130 cm.sup.−1 of the measurement spectrum, a minimum value (b) near 967 cm.sup.−1 which indicates a trans-1,4 bond, a minimum value (c) near 911 cm.sup.−1 which indicates a vinyl bond, and a minimum value (d) near 736 cm.sup.−1 which indicates a cis-1,4 bond.

(26) 2) Weight-Average Molecular Weight (Mw), Number-Average Molecular Weight (Mn), and Molecular Weight Distribution (MWD)

(27) Each polymer was dissolved in tetrahydrofuran (THF) at 40° C. for 30 minutes, and then loaded and flowed into a gel permeation chromatography (GPC) column. In this case, as the column, two PLgel Olexis (product name) columns by Polymer Laboratories and one PLgel mixed-C (product name) column by Polymer Laboratories were combined and used. Also, all newly replaced columns were mixed-bed type columns, and polystyrene was used as a GPC standard material.

(28) 3) Mooney Viscosity (MV, ML1+4, @100° C.) (MU) and −S/R (Stress/Relaxation) Value

(29) Mooney viscosity (ML1+4, @100° C.) (MU) of each polymer was measured with a large rotor at a rotor speed of 2±0.02 rpm at 100° C. using MV2000E by Monsanto Company. After each polymer was left standing for 30 minutes or more at room temperature (23±3° C.), 27±3 g of each polymer was taken as a sample used in this case and filled into a die cavity, and Mooney viscosity was measured while applying a torque by operating a platen. Also, a −S/R value (absolute value) was obtained by measuring a slope of change in the Mooney viscosity obtained while the torque was released.

(30) TABLE-US-00002 TABLE 2 Example Comparative Example Category 5 6 7 8 4 5 6 Microstructural Cis-1,4 bond 96.9 96.7 96.8 96.5 96.7 96.6 96.9 analysis Trans-1,4 bond 2.4 2.4 2.3 2.7 2.3 2.5 2.3 Vinyl-1,2 bond 0.7 0.9 0.9 0.8 1.0 0.9 0.8 GPC Mn (×10.sup.5 g/mol) 2.65 2.71 2.75 2.54 2.68 2.43 2.60 results Mw (×10.sup.5 g/mol) 7.23 7.61 8.08 6.86 8.33 7.41 7.93 MWD (Mw/Mn) 2.73 2.81 2.94 2.70 3.11 3.05 3.05 Viscosity Mooney 44 46 45 43 46 41 48 properties viscosity (MV) −S/R 0.7148 0.6820 0.6107 0.6623 0.6017 0.6183 0.6234

(31) As illustrated in Table 2, all of the polymers of Examples 5 to 8 according to the embodiment of the present invention had a molecular weight distribution of 3.0 or less, wherein the polymers of Examples 5 to 8 exhibited the molecular weight distributions which were significantly decreased by about 6% to about 13% in comparison to the polymer of Comparative Example 4 using the conventional preforming catalyst composition.

(32) Also, with respect to Comparative Examples 5 and 6 in which the catalyst compositions each including the polymer were used, but the number-average molecular weights of the polymers were outside a range of 3,000 g/mol to 10,000 g/mol, since both of molecular weight distributions were greater than 3.0, Comparative Examples 5 and 6 each exhibited a wide molecular weight distribution, and thus, Comparative Examples 5 and 6 respectively had the molecular weight distributions considerably increased in comparison to those of the examples.

(33) From the results of Table 1 and Table 2, it may be confirmed that, in a case in which the number-average molecular weight and molecular weight distribution of the polymer were not controlled in a specific range even if the polymer was included in the catalyst composition, the molecular weight distribution of the polymer prepared may not be controlled.