Modification initiator and modified conjugated diene-based polymer including the same

Abstract

The present invention relates to a modification initiator and a modified conjugated diene-based polymer including the same, and more particularly, the present invention provides a modification initiator including a compound represented by Formula 1, a modified conjugated diene-based polymer including the same, and a method of preparing a modified conjugated diene-based polymer.

Claims

1. A modified conjugated diene-based polymer comprising a conjugated diene-based monomer-derived repeating unit, and a modification initiator-derived function group including a compound represented by Formula 1 at one end, ##STR00019## wherein, in Formula 1, Y.sup.1 and Y.sup.2 are each independently M or R.sup.15, wherein Y.sup.2 is R.sup.15 when Y.sup.1 is M, and Y.sup.2 is M when Y.sup.1 is R.sup.15, M is an alkali metal, R.sup.1, R.sup.2 and R.sup.15 are each independently hydrogen; an alkyl group having 1 to 30 carbon atoms; an alkenyl group having 2 to 30 carbon atoms; an alkynyl group having 2 to 30 carbon atoms; a heteroalkyl group having 1 to 30 carbon atoms which includes a nitrogen (N), oxygen (O), or sulfur (S) atom; a heteroalkenyl group having 2 to 30 carbon atoms which includes an N, O, or S atom; a heteroalkynyl group having 2 to 30 carbon atoms which includes an N, O, or S atom; a cycloalkyl group having 5 to 30 carbon atoms; an aryl group having 5 to 30 carbon atoms; or a heterocyclic group having 3 to 30 carbon atoms which includes at least one of N, O, and S atoms, R.sup.3 is hydrogen, R.sup.4 is a single bond; an alkylene group having 1 to 20 carbon atoms which is substituted or unsubstituted with an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 5 to 20 carbon atoms; a cycloalkylene group having 5 to 20 carbon atoms which is substituted or unsubstituted with an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 5 to 20 carbon atoms; or an arylene group having 5 to 20 carbon atoms which is substituted or unsubstituted with an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 5 to 20 carbon atoms, R.sup.5 is an alkyl group having 1 to 30 carbon atoms; an alkenyl group having 2 to 30 carbon atoms; an alkynyl group having 2 to 30 carbon atoms; a heteroalkyl group having 1 to 30 carbon atoms which includes an N, O, or S atom; a heteroalkenyl group having 2 to 30 carbon atoms which includes an N, O, or S atom; a heteroalkynyl group having 2 to 30 carbon atoms which includes an N, O, or S atom; a cycloalkyl group having 5 to 30 carbon atoms; an aryl group having 5 to 30 carbon atoms; a heterocyclic group having 3 to 30 carbon atoms which includes at least one of N, O, and S atoms; a functional group represented by Formula 2; or a functional group represented by Formula 3, n is an integer selected from 1 to 5, at least one of R.sup.5 is the functional group represented by Formula 2 or 3, and a plurality of R.sup.5 are the same or different from each other when n is an integer selected from 2 to 5, ##STR00020## wherein, in Formulae 2 and 3, R.sup.6 and R.sup.10 are each independently an alkylene group having 1 to 20 carbon atoms which is substituted or unsubstituted with an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 5 to 20 carbon atoms; a cycloalkylene group having 5 to 20 carbon atoms which is substituted or unsubstituted with an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 5 to 20 carbon atoms; or an arylene group having 5 to 20 carbon atoms which is substituted or unsubstituted with an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 5 to 20 carbon atoms, R.sup.7, R.sup.8, and R.sup.12 are each independently an alkylene group having 1 to 20 carbon atoms which is substituted or unsubstituted with an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 5 to 20 carbon atoms, R.sup.9 is an alkyl group having 1 to 30 carbon atoms; an alkenyl group having 2 to 30 carbon atoms; an alkynyl group having 2 to 30 carbon atoms; a heteroalkyl group having 1 to 30 carbon atoms which includes an N, O, or S atom; a heteroalkenyl group having 2 to 30 carbon atoms which includes an N, O, or S atom; a heteroalkynyl group having 2 to 30 carbon atoms which includes an N, O, or S atom; a cycloalkyl group having 5 to 30 carbon atoms; an aryl group having 5 to 30 carbon atoms; a heterocyclic group having 3 to 30 carbon atoms which includes at least one of N, O, and S atoms; an alkenyl group having 2 to 30 carbon atoms which is substituted with an alkyl group having 1 to 10 carbon atoms which includes an alkali metal; or an aryl group having 6 to 30 carbon atoms which is substituted with an alkyl group having 1 to 10 carbon atoms which includes an alkali metal, R.sup.11, R.sup.13, and R.sup.14 are each independently hydrogen; an alkyl group having 1 to 30 carbon atoms; an alkenyl group having 2 to 30 carbon atoms; an alkynyl group having 2 to 30 carbon atoms; a heteroalkyl group having 1 to 30 carbon atoms which includes an N, O, or S atom; a heteroalkenyl group having 2 to 30 carbon atoms which includes an N, O, or S atom; a heteroalkynyl group having 2 to 30 carbon atoms which includes an N, O, or S atom; a cycloalkyl group having 5 to 30 carbon atoms; an aryl group having 5 to 30 carbon atoms; a heterocyclic group having 3 to 30 carbon atoms which includes at least one of N, O, and S atoms; an alkenyl group having 2 to 30 carbon atoms which is substituted with an alkyl group having 1 to 10 carbon atoms which includes an alkali metal; or an aryl group having 6 to 30 carbon atoms which is substituted with an alkyl group having 1 to 10 carbon atoms which includes an alkali metal, X.sup.1 and X.sup.2 are each independently one selected from N, O, and S atoms, R.sup.9 is not present when X.sup.1 is an O or S atom, R.sup.14 is not present when X.sup.2 is an O or S atom, and m is an integer of 1 or 2.

2. The modified conjugated diene-based polymer of claim 1, further comprising an aromatic vinyl monomer-derived repeating unit.

3. The modified conjugated diene-based polymer of claim 1, wherein the modified conjugated diene-based polymer has a number-average molecular weight of 10,000 g/mol to 2,000,000 g/mol, a weight-average molecular weight of 10,000 g/mol to 3,000,000 g/mol, and a molecular weight distribution of 1.0 to 5.0.

4. The modified conjugated diene-based polymer of claim 1, wherein the modified conjugated diene-based polymer has a Mooney viscosity of 10 to 180.

5. The modified conjugated diene-based polymer of claim 1, wherein the modified conjugated diene-based polymer has a vinyl bond content in the conjugated diene-based monomer-derived repeating unit of 5 wt % to 50 wt % based on the modified conjugated diene-based polymer.

6. The modified conjugated diene-based polymer of claim 1, wherein the compound represented by Formula 1 comprises one selected from the group consisting of compounds represented by Formulae 1-1 to 1-13: ##STR00021## ##STR00022## wherein, in Formulae 1-1 to 1-13, M is an alkali metal, R.sup.15 is hydrogen; an alkyl group having 1 to 30 carbon atoms; an alkenyl group having 2 to 30 carbon atoms; and an alkynyl group having 2 to 30 carbon atoms, and R.sup.24 is hydrogen or an alkyl group having 1 to 8 carbon atoms.

7. The modified conjugated diene-based polymer of claim 1, further comprising a modifier-derived functional group, which includes a compound represented by Formula 4, at the other end: ##STR00023## wherein, in Formula 4, R.sup.16 and R.sup.17 are each independently hydrogen, a hydrocarbon group having 1 to 30 carbon atoms, or a glycol unit represented by ##STR00024## R.sup.18 is a divalent hydrocarbon group having 1 to 30 carbon atoms, R.sup.19 to R.sup.22 are each independently a monovalent hydrocarbon group having 1 to 30 carbon atoms, R.sup.23 is a divalent hydrocarbon group having 1 to 10 carbon atoms, j and k are each independently 0 or 1, z is an integer selected from 1 to 10, at least one of R.sup.16 and R.sup.17 is a glycol unit represented by ##STR00025## i and 3-i-1 are each independently 1 or 2, but are not 2 at the same time, and 1 is 0 or 1 when R.sup.16 is a glycol unit represented by ##STR00026## i and 1 are each independently 1 or 2, but are not 2 at the same time, and 3-i-1 is 0 or 1 when R.sup.17 is a glycol unit represented by ##STR00027## and i is 1 or 2, and 1 and 3-i-1 are each independently 0 or 1, but are not 0 at the same time when both R.sup.16 and R.sup.17 are glycol units represented by ##STR00028##

8. The modified conjugated diene-based polymer of claim 7, wherein in Formula 4, R.sup.16 and R.sup.17 are each independently a glycol unit represented by ##STR00029## R.sup.18 is an alkylene group having 1 to 10 carbon atoms, R.sup.19 to R.sup.22 are each independently an alkyl group having 1 to 10 carbon atoms, R.sup.23 is an alkylene group having 1 to 5 carbon atoms, i is 1 or 2, j and k are each independently 0 or 1, 1 and 3-i-1 are each independently 0 or 1, but are not 0 at the same time, and n is an integer selected from 2 to 8.

9. The modified conjugated diene-based polymer of claim 7, wherein the compound represented by Formula 4 comprises one selected from the group consisting of compounds represented by Formulae 4a to 4e: ##STR00030## wherein, in Formulae 4a to 4e, Me is a methyl group, Et is an ethyl group, and nBu is an n-butyl group.

Description

EXAMPLES

Example 1

(1) 85 wt % of n-hexane, from which impurities, such as moisture, were removed, and 15 wt % of a monomer mixture (73 wt % of butadiene and 27 wt % of styrene) were continuously added at a total flow rate of 400 g/hr to a raw material input line of a first reactor among three continuous stirred-tank reactors (CSTR). Also, as an initiator for initiating a reaction, n-butyllithium and 1-phenyl-4-(4-vinylbenzyl)piperazine were added in a molar ratio of 1:1 to the input line, and ditetrahydrofurylpropane (DTP), as a polar additive, was added in a molar ratio of 0.5 to 3 with respect to a molar amount of the n-butyllithium. Next, an internal temperature of the reactor was controlled to be in a range of 70° C. to 85° C. and was maintained for 30 minutes to 60 minutes. Thereafter, a polymer of the first reactor thus obtained was continuously supplied to the top of a second reactor, and an internal temperature of the reactor was controlled to be in a range of 70° C. to 85° C. and was maintained for 60 minutes so that a polymerization conversion rate was 90%. A polymer of the second reactor thus obtained was continuously supplied to the top of a third reactor, N,N-bis(3-diethoxy(methyl)silyl)propyl)-2,5,8,11,14-pentaoxahexadecane-16-amine was continuously supplied in a molar amount equivalent to that of the n-butyllithium to perform a modification reaction. A solution including 5 wt % to 10 wt % of ethyl alcohol and 25 wt % to 35 wt % of an antioxidant (Wingstay-K) was added to a polymer of the third reactor thus obtained at a rate of 0.1556 ml/min to stop the polymerization reaction, and a polymer was obtained. After the polymer obtained was put in hot water heated by steam and stirred to remove the solvent, the residual solvent and water were removed by roll drying to prepare a modified conjugated diene-based polymer. The results of the analysis of the modified conjugated diene-based polymer thus prepared are presented in Table 1 below.

Example 2

(2) Example 2 was performed in the same manner as in Example 1 except that N,N-bis(3-diethoxy(methyl)silyl)propyl)-2,5,8,11,14-pentaoxahexadecane-16-amine was not added in Example 1.

Example 3

(3) Polymerization was performed in the same manner as in Example 2, but the amount of the polymerization initiator (NBL, 1-phenyl-4-(4-vinylbenzyl)piperazine) added was reduced to 20% to 30% of that of Example 2 so that Mooney viscosity or molecular weight of the final polymer was adjusted similar to that of Example 1.

Comparative Example 1

(4) Comparative Example 1 was performed in the same manner as in Example 1 except that the polymerization was performed without the addition of 1-phenyl-4-(4-vinylbenzyl)piperazine, and the polymerization reaction was stopped without the addition of N,N-bis(3-diethoxy(methyl)silyl)propyl)-2,5,8,11,14-pentaoxahexadecane-16-amine in Example 1.

Experimental Example 1

(5) A weight-average molecular weight (Mw, ×10.sup.3 g/mol), a number-average molecular weight (Mn, ×10.sup.3 g/mol), a molecular weight distribution (MWD), Mooney viscosity (MV), a styrene monomer (SM) content, and a vinyl content were respectively measured for the modified or unmodified conjugated diene-based polymers prepared in the examples and comparative example. The results thereof are presented in Table 1 below.

(6) The weight-average molecular weight (Mw) and the number-average molecular weight (Mn) were measured by gel permeation chromatograph (GPC) analysis, and the molecular weight distribution (MWD, Mw/Mn) was obtained by calculation using each molecular weight measured. Specifically, with respect to the GPC, two PLgel Olexis columns (Polymer Laboratories) and one PLgel mixed-C column (Polymer Laboratories) were combined and used, all newly replaced columns were mixed-bed type columns, and polystyrene (PS) was used as a GPC standard material for the calculation of the molecular weight.

(7) The Mooney viscosity (MV, (ML1+4, @100° C.) MU) was measured with a large rotor at a rotor speed of 2±0.02 rpm at 100° C. using MV-2000 (ALPHA Technologies). After samples used in this case were left standing for 30 minutes or more at room temperature (23±3° C.), 27±3 g of each sample was taken and filled into a die cavity, and the Mooney viscosity was measured for 4 minutes by operating a platen.

(8) The styrene monomer (SM) content and the vinyl content were measured using nuclear magnetic resonance (NMR).

(9) TABLE-US-00001 TABLE 1 Comparative Example Example Category 1 2 3 1 Mw (×10.sup.3) 704 589 648 544 Mn (×10.sup.3) 332 299 349 281 MWD 2.12 1.97 1.86 1.94 MV 75.9 64.1 78.9 62.3 SM 27.7 27.8 27.7 27.3 Vinyl 39.6 39.6 40.8 39.9

Experimental Example 2

(10) In order to comparatively analyze physical properties of rubber compositions including each of the modified or unmodified conjugated diene-based polymers prepared in the examples and comparative example and molded articles prepared therefrom, tensile properties, abrasion resistance, and wet road surface resistance were respectively measured, and the results thereof are presented in Table 3 below.

(11) 1) Preparation of Rubber Samples

(12) Each of the modified or unmodified styrene-butadiene copolymers of the examples and comparative example was used as a raw material rubber and was mixed under mixing conditions shown in Table 2 below. An amount of each raw material in Table 2 was represented by parts by weight based on 100 parts by weight of the rubber.

(13) TABLE-US-00002 TABLE 2 Amount Category Raw material (parts by weight) First stage kneading Rubber (rubber excluding 137.5 (100) oil content) Silica 70 Coupling agent 11.2 Process oil 25 Zinc white 3 Stearic acid 2 Antioxidant 2 Anti-aging agent 2 Wax 1 Second stage kneading Rubber accelerator 1.75 Sulfur 1.5 Vulcanization 2 accelerator

(14) Specifically, the rubber samples were kneaded through first stage kneading and second stage kneading. In the first stage kneading, the raw material rubber (styrene-butadiene copolymer), filler, organosilane coupling agent, process oil, zinc white, stearic acid, antioxidant, anti-aging agent, and wax were kneaded using a Banbury mixer equipped with a temperature control device. In this case, a temperature of the mixer was controlled and a primary formulation was obtained at a discharge temperature of 145° C. to 155° C. In the second stage kneading, after the primary formulation was cooled to room temperature, the primary formulation, rubber accelerator, sulfur, and vulcanization accelerator were added to the mixer, and mixing was performed at a temperature of 100° C. or less to obtain a secondary formulation. Thereafter, a curing process was performed at 160° C. for 20 minutes to prepare each rubber sample.

(15) 2) Tensile Properties

(16) Each specimen was prepared according to the tensile test method of ASTM 412, and tensile strength at break of the specimen and tensile stress at 300% elongation (300% modulus) were measured for tensile properties. Specifically, the tensile properties were measured at a rate of 50 cm/min at room temperature using a tensile testing machine, a Universal Test Machine 4204 (Instron).

(17) 3) Abrasion Resistance

(18) Abrasion resistances of the rubber samples prepared were measured using a DIN abrasion tester in such a manner that, after a load of 10 N was applied to a rotating drum with abrasive paper and each rubber sample was moved in a direction perpendicular to a rotational direction of the drum, an abrasion weight loss was measured. A rotational speed of the drum was 40 rpm, and a total movement of the sample at the completion of the test was 40 m. The smaller the weight loss was, the better the abrasion resistance was.

(19) 4) Viscoelastic Properties

(20) With respect to viscoelastic properties, tan δ was measured in a torsion mode at a frequency of 10 Hz while changing a strain at each measurement temperature (−60° C. to 70° C.) using a dynamic mechanical analyzer (TA Instruments). The Payne effect was expressed as the difference between the maximum value and the minimum value at a strain of 0.28% to 40%. The higher the tan δ at a low temperature of 0° C. was, the better the wet road surface resistance was, and the lower the tan δ at a high temperature of 60° C. was, the lower the hysteresis loss was and the better the low running resistance (fuel economy) was.

(21) TABLE-US-00003 TABLE 3 Comparative Example Example Catetgory 1 2 3 1 Tensile 300% 128.1 121.5 122.9 116.9 properties modulus (kgf/cm.sup.2) Tensile 196 193 197 189 strength (kgf/cm.sup.2) Abrasion Weight 14.4 14.2 14.1 14.6 resistance loss (mg) Viscoelasticity tan δ@0° C. 0.906 0.878 0.875 0.818 tan 0.092 0.098 0.097 0.110 δ@60° C.

(22) As illustrated in Table 3, with respect to Examples 2 and 3 prepared according to the present invention, it may be confirmed that tensile properties, abrasion resistance, wet road surface resistance, and low fuel consumption property were all improved in comparison to those of Comparative Example 1 in which modification was not performed. Particularly, with respect to Example 1 in which both ends were modified by using the modification initiator and the modifier, it may be confirmed that the tensile properties, wet road surface resistance, and low fuel consumption property were significantly improved.

(23) From the above results, since the modified conjugated diene-based polymer polymerized using the modification initiator of the present invention had excellent mutual dispersibility with an inorganic filler by including a modification initiator-derived function group at one end, it may be confirmed that processability, tensile properties, abrasion resistance, rolling resistance, and wet road surface resistance were excellent. Furthermore, since the affinity with the inorganic filler was maximized by additional modification at the other end of the modified conjugated diene-based polymer with the modifier in addition to the one end including the modification initiator-derived function group, it may be confirmed that the tensile properties, wet road surface resistance, and low fuel consumption property were significantly improved.