Modified conjugated diene-based polymer and rubber composition including the same
A modified conjugated diene-based polymer, and more particularly, a modified conjugated diene-based polymer prepared by continuous polymerization and having remarkable processability, narrow molecular weight distribution and excellent physical properties, and a rubber composition including the same.
1. A modified conjugated diene-based polymer, comprising:
a functional group derived from a modification initiator represented by the following Formula 1 at one terminal and a functional group derived from a modifier represented by the following Formula 2 or Formula 3 at the other terminal,
in Formula 1,
R 1 to R 5 , R a and R b are each independently hydrogen; an alkyl group of 1 to 20 carbon atoms; a cycloalkyl group of 3 to 20 carbon atoms; an aryl group of 6 to 20 carbon atoms; an arylalkyl group of 7 to 20 carbon atoms; an alkylaryl group of 7 to 20 carbon atoms; or a heteroalkyl group of 1 to 20 carbon atoms including a heteroatom, and
n is an integer of 0 to 3,
in Formula 2,
R 20 and R 23 are each independently a single bond, or an alkylene group of 1 to 10 carbon atoms,
R 21 and R 22 are each independently an alkyl group of 1 to 10 carbon atoms,
R 24 is hydrogen, an alkyl group of 1 to 10 carbon atoms, or a substituted divalent, trivalent or tetravalent alkylsilyl group with an alkyl group of 1 to 10 carbon atoms,
a is an integer of 1 or 3,
c is an integer of 1 to 3, and b is an integer of 0 to 2, where b+c=3,
in Formula 3,
A 1 and A 2 are each independently an alkylene group of 1 to 20 carbon atoms,
R 25 to R 28 are each independently an alkyl group of 1 to 20 carbon atoms, and
L 1 to L 4 are each independently a substituted divalent, trivalent or tetravalent alkylsilyl group with an alkyl group of 1 to 10 carbon atoms, or an alkyl group of 1 to 20 carbon atoms,
wherein the modified conjugated diene-based polymer has a unimodal shape molecular weight distribution curve by gel permeation chromatography (GPC), and
a molecular weight distribution (MWD) of 1.0 or more and less than 1.7.
2. The modified conjugated diene-based polymer according to claim 1 , wherein
in Formula 1,
R 1 is an alkyl group of 1 to 10 carbon atoms,
R 2 to R 5 , R a and R b are each independently hydrogen or an alkyl group of 1 to 10 carbon atoms.
3. The modified conjugated diene-based polymer according to claim 1 , wherein
in Formula 2,
R 20 and R 23 are each independently a single bond, or an alkylene group of 1 to 5 carbon atoms,
R 21 and R 22 are each independently an alkyl group of 1 to 5 carbon atoms, and
R 24 is hydrogen, an alkyl group of 1 to 5 carbon atoms, or a substituted tetravalent alkylsilyl group with an alkyl group of 1 to 5 carbon atoms.
4. The modified conjugated diene-based polymer according to claim 1 , wherein
in Formula 3,
A 1 and A 2 are each independently an alkylene group of 1 to 10 carbon atoms,
R 25 to R 28 are each independently an alkyl group of 1 to 10 carbon atoms, and
L 1 to L 4 are each independently a substituted tetravalent alkylsilyl group with an alkyl group of 1 to 5 carbon atoms, or an alkyl group of 1 to 10 carbon atoms.
5. The modified conjugated diene-based polymer according to claim 1 , wherein the modified conjugated diene-based polymer has a number average molecular weight (Mn) of 1,000 g/mol to 2,000,000 g/mol, and a weight average molecular weight (Mw) of 1,000 g/mol to 3,000,000 g/mol.
6. The modified conjugated diene-based polymer according to claim 1 , wherein the modified conjugated diene-based polymer has a Si content and a N content of 50 ppm or more based on a weight, respectively.
7. The modified conjugated diene-based polymer according to claim 1 , wherein the modified conjugated diene-based polymer has a Mooney stress-relaxation ratio measured at 100° C. of 0.7 to 3.0.
8. The modified conjugated diene-based polymer according to claim 1 , wherein the modified conjugated diene-based polymer has a shrinking factor which is obtained by measurement using a gel permeation chromatography-light scattering method provided with a viscometer of 1.0 to 3.0.
9. The modified conjugated diene-based polymer according to claim 1 , wherein the modified conjugated diene-based polymer has a coupling number (C.N.) of 1<C.N.<F, where F is a number of functional groups of the modifier.
10. A rubber composition comprising the modified conjugated diene-based polymer described in claim 1 and a filler.
11. The rubber composition according to claim 10 , wherein the rubber composition comprises 0.1 parts by weight to 200 parts by weight of the filler based on 100 parts by weight of the modified conjugated diene-based polymer.
12. The rubber composition according to claim 10 , wherein the filler is a silica-based filler or a carbon black-based filler.
13. A method for preparing the modified conjugated diene-based polymer of claim 1 comprising:
(S1) polymerizing a conjugated diene-based monomer, or a conjugated diene-based monomer and an aromatic vinyl monomer in the presence of a modification initiator represented by the following Formula 1 in a hydrocarbon solvent to prepare an active polymer including a functional group derived from the modification initiator; and
(S2) reacting or coupling the active polymer prepared in step (S1) with a modifier represented by Formula 2 or Formula 3 below,
wherein the step (S1) is continuously performed in two or more polymerization reactors, and a polymerization conversion ratio in a first reactor among the polymerization reactors is 50% or less,
in Formula 1,
R 1 to R 5 , R a and R b are each independently hydrogen; an alkyl group of 1 to 20 carbon atoms;
a cycloalkyl group of 3 to 20 carbon atoms; an aryl group of 6 to 20 carbon atoms; an arylalkyl group of 7 to 20 carbon atoms; an alkylaryl group of 7 to 20 carbon atoms; or a heteroalkyl group of 1 to 20 carbon atoms including a heteroatom, and
n is an integer of 0 to 3,
in Formula 2,
R 20 and R 23 are each independently a single bond, or an alkylene group of 1 to 10 carbon atoms,
R 21 and R 22 are each independently an alkyl group of 1 to 10 carbon atoms,
R 24 is hydrogen, an alkyl group of 1 to 10 carbon atoms, or a substituted divalent, trivalent or tetravalent alkylsilyl group with an alkyl group of 1 to 10 carbon atoms,
a is an integer of 1 to 3,
c is an integer of 1 to 3, and b is an integer of 0 to 2, where b+c=3,
in Formula 3,
A 1 and A 2 are each independently an alkylene group of 1 to 20 carbon atoms,
R 25 to R 28 are each independently an alkyl group of 1 to 20 carbon atoms, and
L 1 to L 4 are each independently a substituted divalent, trivalent or tetravalent alkylsilyl group with an alkyl group of 1 to 10 carbon atoms, or an alkyl group of 1 to 20 carbon atoms.