U.S. patent application number 14/381123 was filed with the patent office on 2016-08-25 for modified conjugated diene polymer, method for preparing the same and rubber composition comprising the same.
The applicant listed for this patent is (LG CHEM, LTD). Invention is credited to Heung Yeal CHOI, Young Chel CHOI, Moon Seok CHUN, Kyoung Hoon KIM, Ro Mi LEE, Sang Mi LEE.
Application Number | 20160244589 14/381123 |
Document ID | / |
Family ID | 52628563 |
Filed Date | 2016-08-25 |
United States Patent
Application |
20160244589 |
Kind Code |
A1 |
LEE; Sang Mi ; et
al. |
August 25, 2016 |
MODIFIED CONJUGATED DIENE POLYMER, METHOD FOR PREPARING THE SAME
AND RUBBER COMPOSITION COMPRISING THE SAME
Abstract
Disclosed is a modified conjugated diene polymer represented by
Formula 1. Advantageously, provided are a modified conjugated diene
polymer which exhibits superior compatibility with a reinforcing
filler, heat generation, tensile strength and abrasion resistance,
low fuel consumption and excellent wet skid resistance, a method
for preparing the same and a rubber composition comprising the
same.
Inventors: |
LEE; Sang Mi; (Daejeon,
KR) ; KIM; Kyoung Hoon; (Daejeon, KR) ; CHOI;
Young Chel; (Daejeon, KR) ; LEE; Ro Mi;
(Daejeon, KR) ; CHOI; Heung Yeal; (Daejeon,
KR) ; CHUN; Moon Seok; (Daejeon, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
(LG CHEM, LTD) |
Seoul |
|
KR |
|
|
Family ID: |
52628563 |
Appl. No.: |
14/381123 |
Filed: |
September 3, 2013 |
PCT Filed: |
September 3, 2013 |
PCT NO: |
PCT/KR2013/007915 |
371 Date: |
August 26, 2014 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08F 236/10 20130101;
C08K 3/04 20130101; C08K 3/36 20130101; C08F 236/14 20130101; B60C
1/00 20130101; C08K 3/36 20130101; C08C 19/25 20130101; C08K 5/548
20130101; C07F 7/1804 20130101; C08C 19/44 20130101; C08K 3/04
20130101; C08K 5/548 20130101; C08L 15/00 20130101; C08L 15/00
20130101; C08L 15/00 20130101 |
International
Class: |
C08K 3/36 20060101
C08K003/36; C08K 3/04 20060101 C08K003/04; C07F 7/18 20060101
C07F007/18; C08F 236/14 20060101 C08F236/14 |
Claims
1. A modified conjugated diene polymer represented by the following
Formula 1: ##STR00006## wherein R.sup.1, R.sup.2 and R.sup.3
represent an alkylene group (--(CH.sub.2).sub.n--, n=1.about.15),
R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.9 each independently
represent an alkyl group or an alkylsilyl group, R.sup.8 represents
a C.sub.1-C.sub.15 alkyl group and P is a conjugated diene polymer
chain, and a is an integer of 0 to 2, b is an integer of 0 to 2 and
c is an integer of 1 to 3 with the proviso that a+b+c equals 3.
2. The modified conjugated diene polymer according to claim 1,
wherein the conjugated diene polymer chain is a random copolymer
chain comprising an aromatic diene monomer and an aromatic vinyl
monomer.
3. The modified conjugated diene polymer according to claim 1,
wherein the modified conjugated diene polymer has a number average
molecular weight of 1,000 to 2,000,000 g/mol.
4. The modified conjugated diene polymer according to claim 1,
wherein the modified conjugated diene polymer has a vinyl content
of 25% or more.
5. The modified conjugated diene polymer according to claim 1,
wherein the modified conjugated diene polymer chain comprises
0.0001 to 40% by weight of the aromatic vinyl monomer, based on
100% by weight in total of the conjugated diene monomer and the
aromatic vinyl monomer.
6. The modified conjugated diene polymer according to claim 1,
wherein the modified conjugated diene polymer has a Mooney
viscosity of 40 or more.
7. A method for preparing a modified conjugated diene polymer
comprising: (a) polymerizing a conjugated diene monomer, or a
mixture of the conjugated diene monomer and an aromatic vinyl
monomer in the presence of a solvent containing an organometallic
compound to prepare an active conjugated diene polymer chain having
a metal end; and (b) modifying the active conjugated diene polymer
chain with a compound represented by the following Formula 2 as a
modifying agent: ##STR00007## wherein R.sup.1, R.sup.2 and R.sup.3
represent an alkylene group (--(CH.sub.2).sub.n--, n=1.about.15),
R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.9 each independently
represent an alkyl group or an alkylsilyl group, R.sup.8 represents
a C.sub.1-C.sub.15 alkyl group and m is an integer of 0 to 2.
8. The method according to claim 7, wherein the organometallic
compound is used in an amount of 0.01 to 10 mmol, based on 100 g in
total of the monomer.
9. The method according to claim 7, wherein a molar ratio of the
organometallic compound to the compound represented by Formula 2 is
1:0.1 to 1:10.
10. The method according to claim 7, wherein the polymerization
further comprises adding a polar additive.
11. The method according to claim 10, wherein the polar additive is
added in an amount of 0.001 to 50 g, based on 100 g in total of the
monomer.
12. A modified conjugated diene polymer prepared by the method
according to claim 7.
13. A rubber composition comprising 0.1 to 200 parts by weight of a
reinforcing filler with respect to 100 parts by weight of the
modified conjugated diene polymer according to claim 6.
14. The rubber composition according to claim 13, wherein the
rubber composition comprises: 100 parts by weight of a polymer
mixture of 10 to 100% by weight of the modified conjugated diene
polymer and 0 to 90% by weight of another rubber; 5 to 200 parts by
weight of silica; and 2 to 20 parts by weight of a silane coupling
agent.
15. The rubber composition according to claim 13, wherein the
rubber composition further comprises 0.1 to 100 parts by weight of
carbon black.
16. The rubber composition according to claim 13, wherein the
reinforcing filler is a silica filler.
17. A tire comprising the rubber composition according to claim
13.
18. A modifying agent comprising a compound represented by the
following Formula 2: ##STR00008## wherein R.sup.1, R.sup.2 and
R.sup.3 represent an alkylene group (--(CH.sub.2).sub.n--,
n=1.about.15), R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.9 each
independently represent an alkyl group or an alkylsilyl group,
R.sup.8 represents a C.sub.1-C.sub.15 alkyl group and m is an
integer of 0 to 2.
Description
TECHNICAL FIELD
[0001] The present invention relates to a modified conjugated diene
polymer, a method for preparing the same and a rubber composition
comprising the same. The present invention relates to a modified
conjugated diene polymer which exhibits superior compatibility with
a reinforcing filler, heat generation, tensile strength and
abrasion resistance, low fuel consumption and excellent wet skid
resistance, a method for preparing the same and a rubber
composition comprising the same.
BACKGROUND ART
[0002] Concerns about environments including inhibition of carbon
dioxide are socially demanded. As such, there is a growing demand
for low fuel consumption of vehicles. Accordingly, there is an
increasing demand for materials having superior wet skid
resistance, abrasion resistance and breaking strength as materials
for vehicle tires, in particular, tire treads contacting the
roads.
[0003] Meanwhile, carbon black, silica and the like are used as
reinforcing fillers for tire treads. When silica is used as a
reinforcing filler, advantageously, hysteresis loss is reduced or
wet skid resistance is improved. As compared to carbon black having
a hydrophobic surface, silica having a hydrophilic surface has a
disadvantage of low dispersibility of silica in rubbers due to low
affinity to conjugated diene rubbers. Accordingly, use of
additional silane coupling agent is required to improve
dispersibility of silica in rubbers or form silica-rubber
bonds.
[0004] In order to solve these problems, functional groups having
affinity or reactivity to silica are introduced into an end of
rubber molecules to improve dispersibility of silica in conjugated
diene rubbers and implement sealing through bonding between the end
of rubber molecules and silica particles and thereby reduce
hysteresis loss.
DISCLOSURE
Technical Problem
[0005] Therefore, as a result of extensive research to address the
problems of the related art, the present inventors discovered that
silica used as a reinforcing filler provides a modified conjugated
diene polymer which exhibits superior compatibility, heat
generation, tensile strength and abrasion resistance, low fuel
consumption and excellent wet skid resistance, and a rubber
composition comprising the same. The present invention has been
completed based on this discovery.
[0006] It is one object of the present invention to provide a
modified conjugated diene polymer which exhibits superior
compatibility with an inorganic filler, heat generation, tensile
strength and abrasion resistance, low fuel consumption and
excellent wet skid resistance.
[0007] It is another object of the present invention to provide a
method for preparing the modified conjugated diene polymer.
[0008] It is another object of the present invention to provide a
rubber composition comprising the modified conjugated diene polymer
and a tire comprising the rubber composition.
[0009] It is yet another object of the present invention to provide
a modifying agent used for preparation of the modified conjugated
diene polymer.
[0010] The above and other objects can be accomplished by the
present disclosure given below.
Technical Solution
[0011] In accordance with one aspect of the present invention,
provided is a modified conjugated diene polymer represented by the
following Formula 1:
##STR00001##
[0012] wherein R.sup.1, R.sup.2 and R.sup.3 represent an alkylene
group (--(CH.sub.2).sub.n--, n=1.about.15), R.sup.4, R.sup.5,
R.sup.6, R.sup.7 and R.sup.9 each independently represent an alkyl
group or an alkylsilyl group, R.sup.8 represents a C.sub.1-C.sub.15
alkyl group, and P is a conjugated diene polymer chain.
[0013] In Formula 1, a is an integer of 0 to 2, b is an integer of
0 to 2, and c is an integer of 1 to 3 with the proviso that a+b+c
equals 3.
[0014] In Formula 1, the conjugated diene polymer chain is a
conjugated diene monomer, or a copolymer of a conjugated diene
monomer and an aromatic vinyl monomer.
[0015] In accordance with another aspect of the present invention,
provided is a method for preparing a modified conjugated diene
polymer comprising (a) polymerizing a conjugated diene monomer, or
a mixture of a conjugated diene monomer and an aromatic vinyl
monomer in the presence of a solvent containing an organometallic
compound to prepare an active conjugated diene polymer having a
metal end, and (b) modifying the active conjugated diene polymer
with a compound represented by the following Formula 2 as a
modifying agent:
##STR00002##
[0016] wherein R.sup.1, R.sup.2 and R.sup.3 represent an alkylene
group (--(CM.sub.2).sub.n--, n=1.about.15), R.sup.4, R.sup.5,
R.sup.6, R.sup.7 and R.sup.9 each independently represent an alkyl
group or an alkylsilyl group, R.sup.8 represents a C.sub.1-C.sub.15
alkyl group and m is an integer of 0 to 2.
[0017] In accordance with another aspect of the present invention,
provided is a rubber composition comprising 0.1 to 200 parts by
weight of a reinforcing filler with respect to 100 parts by weight
of the modified conjugated diene polymer.
[0018] In accordance with another aspect of the present invention,
provided is a tire comprising the rubber composition.
[0019] In accordance with yet another aspect of the present
invention, provided is a modifying agent used for preparation of
the modified conjugated diene polymer.
Advantageous Effects
[0020] As apparent from the foregoing, the rubber composition
comprising the modified conjugated diene polymer according to the
present invention, when mixed with silica as a reinforcing filler,
advantageously, exhibits superior compatibility with a reinforcing
filler, heat generation, tensile strength and abrasion resistance,
low fuel consumption and excellent wet skid resistance.
BEST MODE
[0021] Hereinafter, the modified conjugated diene polymer, the
method for preparing the same, the rubber composition comprising
the same, the tire comprising the rubber composition and the like
will be described in detail.
[0022] The modified conjugated diene polymer according to the
present invention comprises a polymer represented by the following
Formula 1:
##STR00003##
[0023] wherein R.sup.1, R.sup.2 and R.sup.3 represent an alkylene
group (--(CH.sub.2).sub.n--, n=1.about.15), R.sup.4, R.sup.5,
R.sup.6, R.sup.7 and R.sup.9 each independently represent an alkyl
group or an alkylsilyl group, R.sup.8 represents a C.sub.1-C.sub.15
alkyl group, and P is a conjugated diene polymer chain.
[0024] In Formula 1, a is an integer of 0 to 2, b is an integer of
0 to 2 and c is an integer of 1 to 3 with the proviso that a+b+c
equals 3.
[0025] R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.9 are for
example an alkyl group or a C.sub.1-C.sub.15 alkyl group.
[0026] R.sup.1, R.sup.2 and R.sup.3 are for example an alkylene
group, preferably, a C.sub.1-C.sub.15 alkylene group.
[0027] In another example, R.sup.4, R.sup.2 and R.sup.3 are a
bivalent alkylsilyl group, preferably, a bivalent C.sub.1-C.sub.15
alkylsilyl group.
[0028] The alkylsilyl group according to the present invention is,
for example, a linked group such as alkylene-silyl-alkylene,
silyl-alkylene or alkylene-silyl.
[0029] The conjugated diene polymer chain is for example a
conjugated diene monomer, or a copolymer of the conjugated diene
monomer and an aromatic vinyl monomer.
[0030] In another example, the conjugated diene polymer chain may
be a polymer chain comprising 0.0001 to 40% by weight, preferably
10 to 35% by weight, more preferably 20 to 30% by weight of the
aromatic vinyl monomer, based on 100% by weight in total of the
conjugated diene monomer and the aromatic vinyl monomer.
[0031] The conjugated diene polymer may be for example a random
copolymer of the conjugated diene monomer and the aromatic vinyl
monomer.
[0032] The conjugated diene monomer, for example, comprises at
least one selected from the group consisting of 1,3-butadiene,
2,3-dimethyl-1,3-butadiene, piperylene, 3-butyl-1,3-octadiene,
isoprene, and 2-phenyl-1,3-butadiene. In another example, the
conjugated diene monomer may be 1,3-butadiene, but the present
invention is not limited thereto.
[0033] The aromatic vinyl monomer, for example, comprises at least
one selected from the group consisting of styrene,
.alpha.-methylstyrene, 3-methylstyrene, 4-methylstyrene,
4-propylstyrene, 1-vinylnaphthalene, 4-cyclohexylstyrene,
4-(p-methylphenyl)styrene, and 1-vinyl-5-hexylnaphthalene. In
another example, the aromatic vinyl monomer is styrene or
.alpha.-methylstyrene, but the present invention is not limited
thereto.
[0034] The modified conjugated diene polymer, for example, has a
Mooney viscosity of 40 or higher, preferably 40 to 90, more
preferably 45 to 85, most preferably 50 to 80.
[0035] The modified conjugated diene polymer, for example, has a
number average molecular weight of 1,000 to 2,000,000 g/mol,
preferably 10,000 to 1,000,000 g/mol, more preferably 100,000 to
500,000 g/mol.
[0036] The conjugated diene polymer, for example, has a vinyl
content of 25% or higher, preferably 30 to 70%, more preferably 40
to 60%. Within this range, there are advantages in that glass
transition temperature of the polymer is increased, properties,
such as running resistance and brake power, required for produced
tires are satisfied and fuel consumption is reduced.
[0037] The vinyl content means a content of a unit having a vinyl
group, or a content of a 1,2-added conjugated diene monomer rather
than a 1,4-added conjugated diene monomer with respect to 100% by
weight of the conjugated diene monomer.
[0038] The modified conjugated diene polymer may, for example, have
a polydispersity index (PDI) of 0.5 to 10, preferably 0.5 to 5,
more preferably 1.0 to 2.0.
[0039] Regarding viscoelasticity, the modified conjugated diene
polymer, for example, has a Tan .delta. at 0.degree. C. (loss
modulus at 0.degree. C.), measured at 10 Hz by dynamic-mechanical
analysis (DMA) after mixing with silica, of 0.6 to 1, preferably
0.9 to 1. Within this range, there is an effect in that skid
resistance or wet skid resistance is greatly improved, as compared
to the related art.
[0040] In addition, the modified conjugated diene polymer has, for
example, a Tan .delta. at 60.degree. C., of 0.06 to 0.09,
preferably, 0.06 to 0.08. Within this range, rolling resistance or
rotational resistance (RR) is advantageously greatly improved, as
compared to the related art.
[0041] In addition, the present invention provides a method for
preparing a modified conjugated diene polymer according to the
present invention including (a) polymerizing a conjugated diene
monomer, or a mixture of the conjugated diene monomer and an
aromatic vinyl monomer in the presence of a solvent containing an
organometallic compound to prepare an active conjugated diene
polymer having a metal end, and (b) modifying the active conjugated
diene polymer with a compound represented by the following Formula
2 as a modifying agent:
##STR00004##
[0042] wherein R.sup.1, R.sup.2 and R.sup.3 represent an alkylene
group (--(CH.sub.2).sub.n--, n=1.about.15), R.sup.4, R.sup.5,
R.sup.6, R.sup.7 and R.sup.9 each independently represent an alkyl
group or an alkylsilyl group, R.sup.8 represents a C.sub.1-C.sub.15
alkyl group and m is an integer of 0 to 2.
[0043] R.sup.1 to R.sup.9 are defined as above.
[0044] Polymerization
[0045] The conjugated diene polymer, which is an unmodified form of
the modified conjugated diene polymer, is obtained by polymerizing
a conjugated diene monomer, or copolymerizing the conjugated diene
monomer with an aromatic vinyl monomer. Polymerization of the
conjugated diene polymer may be carried out by adding a
polymerization initiator to a reactor for copolymerization of the
conjugated diene monomer or the conjugated diene monomer and the
aromatic vinyl monomer.
[0046] The conjugated diene monomer, for example, comprises at
least one selected from the group consisting of 1,3-butadiene,
2,3-dimethyl-1,3-butadiene, piperylene, 3-butyl-1,3-octadiene,
isoprene, and 2-phenyl-1,3-butadiene. In another example, the
conjugated diene monomer may be 1,3-butadiene, but the present
invention is not limited thereto.
[0047] The aromatic vinyl monomer, for example, comprises at least
one selected from the group consisting of styrene,
.alpha.-methylstyrene, 3-methylstyrene, 4-methylstyrene,
4-propylstyrene, 1-vinylnaphthalene, 4-cyclohexylstyrene,
4-(p-methylphenyl)styrene, and 1-vinyl-5-hexylnaphthalene. In
another example, the aromatic vinyl monomer is styrene or
.alpha.-methylstyrene, but the present invention is not limited
thereto.
[0048] The aromatic vinyl monomer may be present in an amount of
0.0001 to 40% by weight, preferably 10 to 35% by weight, more
preferably 20 to 30% by weight, based on 100% by weight in total of
the conjugated diene monomer and the aromatic vinyl monomer.
[0049] The solvent is for example hydrocarbon and preferably
comprises at least one selected from the group consisting of
n-pentane, n-hexane, n-heptane, isooctane, cyclohexane, toluene,
benzene and xylene.
[0050] The organometallic compound is for example an organic alkali
metal compound and preferably comprises at least one selected from
the group consisting of organolithium compounds, organosodium
compounds, organopotassium compounds, organorubidium compounds and
organocesium compounds.
[0051] In another example, the organometallic compound may comprise
at least one selected from the group consisting of methyl lithium,
ethyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl
lithium, tert-butyl lithium, n-decyl lithium, tert-octyl lithium,
phenyl lithium, 1-naphthyl lithium, n-eicosyl lithium,
4-butylphenyl lithium, 4-tolyl lithium, cyclohexyl lithium,
3,5-di-n-heptylcyclohexyl lithium and 4-cyclopentyl lithium.
[0052] In another example, the organometallic compound is selected
from the group consisting of n-butyl lithium, sec-butyl lithium or
a mixture thereof.
[0053] In another example, the organometallic compound may comprise
at least one selected from the group consisting of naphthyl sodium,
naphthyl potassium, lithium alkoxide, sodium alkoxide, potassium
alkoxide, lithium sulfonate, sodium sulfonate, potassium sulfonate,
lithium amide, sodium amide and potassium amide. The organometallic
compound may be used in combination with another organometallic
compound.
[0054] The organometallic compound is for example used in an amount
of 0.01 to 10 mmol, preferably 0.05 to 5 mmol, more preferably 0.1
to 2 mmol, most preferably 0.1 to 1 mmol, based on 100 g in total
of the monomer.
[0055] A molar ratio of the organometallic compound to the compound
represented by Formula 2 is for example 1:0.1 to 1:10, preferably
1:0.5 to 1:2.
[0056] The active conjugated diene polymer having a metal end means
a polymer wherein a polymer anion is bonded to a metal cation.
[0057] In the method for preparing a modified conjugated diene
polymer according to the present invention, the polymerization may
further comprise adding a polar additive.
[0058] The polar additive is for example a base. In another
example, the polar additive is preferably selected from the group
consisting of ether, amine or a mixture thereof, or is more
preferably selected from the group consisting of tetrahydrofuran,
ditetrahydrofurylpropane, diethylether, cycloamylether, dipropyl
ether, ethylene methyl ether dimethyl ether, ethylene dimethyl
ether, diethylene glycol, dimethyl ether, tertiary
butoxyethoxyethane, bis(2-dimethylaminoethyl)ether,
(dimethylaminoethyl)ethylether, trimethylamine, triethylamine,
tripropylamine, tetramethylethylenediamine and mixtures of two or
more thereof. Most preferred is ditetrahydrofurylpropane,
triethylamine or tetramethylethylenediamine.
[0059] The polar additive may be for example used in an amount of
0.001 to 50 g, 0.001 to 10 g, 0.005 to 1 g, preferably 0.005 to 0.1
g, based on 100 g in total of the added monomer.
[0060] In another example, the polar additive may be used in an
amount of 0.001 to 10 g, preferably 0.005 to 1 g, more preferably
0.005 to 0.1 g, based on 1 mmol in total of the added
organometallic compound.
[0061] When the conjugated diene monomer is copolymerized with the
aromatic vinyl monomer, a block copolymer may be readily prepared
due to difference in reaction speed between the monomers. However,
when the polar additive is added, reaction speed of the vinyl
aromatic compound having a lower reaction speed than the conjugated
diene monomer is increased, and variation of microstructure of the
copolymer corresponding thereto, for example, synthesis of a random
copolymer is advantageously induced.
[0062] The polymerization may be for example anionic
polymerization.
[0063] In another example, the polymerization may be living anionic
polymerization wherein active ends are obtained by growth reaction
by anions.
[0064] The polymerization may be for example polymerization at an
elevated temperature or polymerization at a fixed temperature.
[0065] The polymerization at an elevated temperature means a
polymerization method which includes elevating a reaction
temperature by heating after adding an organometallic compound. The
polymerization at a fixed temperature means a polymerization method
which does not include heating after adding an organometallic
compound.
[0066] A temperature of the polymerization is for example -20 to
200.degree. C., preferably 0 to 150.degree. C., more preferably 10
to 120.degree. C.
[0067] Modification
[0068] The modified conjugated diene polymer may be obtained by
reacting the active conjugated diene copolymer obtained by the
polymerization with the compound represented by Formula 2 as a
modifying agent and the modifying agent may be a compound having a
silyl group substituted by an alkoxy group and a nitrogen atom.
[0069] The modification may be for example carried out by adding
one or more types, preferably, two or three types of the compound
represented by Formula 2.
[0070] In addition, the modification may include reaction, for
example, at 0 to 90.degree. C. for one minute to 5 hours.
[0071] The method for preparing a modified conjugated diene polymer
according to the present invention may be, for example, carried out
by batch or continuous polymerization including one, two or more
reactors.
[0072] The modified conjugated diene polymer may be, for example,
prepared according to the method for preparing a modified
conjugated diene polymer.
[0073] The rubber composition according to the present invention
comprises 100 parts by weight of the modified conjugated diene
polymer and 0.1 to 200 parts by weight of the reinforcing
filler.
[0074] The rubber composition may further comprise, for example,
another rubber.
[0075] The other rubber may be, for example, selected from the
group consisting of styrene-butadiene rubber (SBR), butadiene
rubber (BR), natural rubber and a mixture thereof.
[0076] The styrene-butadiene rubber (SBR) may be, for example, a
solution styrene-butadiene rubber (SSBR).
[0077] The rubber composition according to the present invention
may, for example, comprise 20 to 100 parts by weight of the
modified conjugated diene polymer and 0.1 to 80 parts by weight of
another rubber.
[0078] In another example, the rubber composition may comprise 20
to 99 parts by weight of the modified conjugated diene polymer and
1 to 80 parts by weight of another rubber.
[0079] In another example, the rubber composition may comprise 10
to 100 parts by weight of the modified conjugated diene polymer,
0.1 to 90 parts by weight of another rubber, 5 to 200 parts by
weight of silica and 2 to 20 parts by weight of a silane coupling
agent.
[0080] In another example, the rubber composition may further
comprise 0.1 to 100 parts by weight of carbon black.
[0081] In another example, the rubber composition may comprise 10
to 100 parts by weight of the modified conjugated diene polymer,
0.1 to 90 parts by weight of another rubber, 5 to 200 parts by
weight of silica and 2 to 20 parts by weight of a silane coupling
agent, wherein the total weight of the modified conjugated diene
polymer and the another conjugated diene polymer is 100 parts by
weight.
[0082] The rubber composition according to the present invention
may further comprise 0.1 to 100 parts by weight of carbon
black.
[0083] In another example, the rubber composition according to the
present invention may comprise 100 parts by weight of a polymer
mixture comprising 10 to 100% by weight of the modified conjugated
diene polymer and 0 to 90% by weight of the another conjugated
diene polymer, 5 to 200 parts by weight of silica and 2 to 20 parts
by weight of a silane coupling agent.
[0084] In another example, the rubber composition according to the
present invention may further comprise 0.1 to 100 parts by weight
of carbon black.
[0085] The reinforcing filler may be present in an amount of, for
example, 10 to 150 parts by weight, preferably 50 to 100 parts by
weight.
[0086] The reinforcing filler may be, for example, selected from
the group consisting of carbon black, a silica filler and a mixture
thereof.
[0087] In another example, the reinforcing filler may be silica. In
this case, advantageously, dispersibility is greatly improved and
hysteresis loss is greatly decreased because an end of the modified
conjugated diene polymer is bonded to (or capped with) silica
particles.
[0088] The rubber composition may for example further comprise 1 to
100 parts by weight of an oil.
[0089] The oil may be, for example, a mineral oil, a softening
agent or the like.
[0090] The oil may be, for example, used in an amount of 10 to 100
parts by weight, preferably, 20 to 80 parts by weight, with respect
to 100 parts by weight of the conjugated diene copolymer. Within
this range, there are effects in that properties of the rubber
composition are efficiently exhibited, the rubber composition is
suitably softened and processability is thus excellent.
[0091] The rubber composition may be for example used as a material
for tires or tire treads.
[0092] The tire may comprise the modified conjugated diene polymer
rubber composition.
[0093] The modifying agent according to the present invention is
represented by the following Formula 2:
##STR00005##
[0094] wherein R.sup.1, R.sup.2 and R.sup.3 represent an alkylene
group (--(CH.sub.2).sub.n--, n=1.about.15), R.sup.4, R.sup.5,
R.sup.6, R.sup.7 and R.sup.9 each independently represent an alkyl
group or an alkylsilyl group, R.sup.8 represents a C.sub.1-C.sub.15
alkyl group and m is an integer of 0 to 2.
[0095] Hereinafter, preferred examples will be provided for better
understanding of the present invention. It will be apparent to
those skilled in the art that these examples are only provided to
illustrate the present invention and various modifications and
alterations are possible within the scope and technical range of
the present invention. Such modifications and alterations fall
within the scope of claims included herein.
EXAMPLE
Example 1
[0096] 270 g of styrene, 710 g of 1,3-butadiene, 5,000 g of
n-hexane, and 0.8 g of 2,2-bis(2-oxolanyl)propane as a polar
additive were added to a 20 L autoclave reactor and an inner
temperature of the reactor was elevated to 40.degree. C. When the
inner temperature of the reactor reached 40.degree. C., 4 mmol of
n-butyl lithium was added to the reactor and an adiabatic
temperature-rising reaction was performed until the reaction was
stabilized. About 20 minutes after the adiabatic temperature-rising
reaction was finished, 20 g of 1,3-butadiene was added to the
reactor. After 5 minutes, 5 mmol of
3-dimethylamino-2-((dimethylaminomethyl)propyl)trimethoxysilane was
added as a modifying agent to the reactor and reaction was
performed for 15 minutes. Then, reaction was stopped using ethanol
and 5 ml of a 0.3 wt % solution of butylated hydroxytoluene (BHT)
as an antioxidant in hexane was then added to the reaction
mixture.
[0097] The polymerization product was stirred in warm water heated
by steam to remove the solvent and the resulting solution was then
roll-dried to remove the residual solvent and water, thereby
preparing a modified conjugated diene polymer. Analysis results of
the modified conjugated diene polymer thus prepared are shown in
the following Table 1.
Example 2
[0098] A modified conjugated diene polymer was prepared in the same
manner as in Example 1, except that 3 mmol of
3-dimethylamino-2-((dimethylaminomethyl)propyl)trimethoxysilane was
added as a modifying agent. Analysis results of the modified
conjugated diene polymer are shown in the following Table 1.
Example 3
[0099] A modified conjugated diene polymer was prepared in the same
manner as in Example 1, except that that
3-dimethylamino-2-((dimethylaminomethyl)propyl)triethoxysilane was
added instead of the
3-dimethylamino-2-((dimethylaminomethyl)propyl)trimethoxysilane as
a modifying agent. Analysis results of the modified conjugated
diene polymer are shown in the following Table 1.
Comparative Example 1
[0100] Analysis results of an unmodified conjugated diene polymer
(2550-H, produced by LG Chem., Ltd., Korea) are shown in the
following Table 1.
Comparative Example 2
[0101] A modified conjugated diene polymer was prepared in the same
manner as in Example 1, except that dimethyldichlorosilane was
added as a coupling agent, instead of the
3-dimethylamino-2-((dimethylaminomethyl)propyl)trimethoxysilane.
Analysis results of the modified conjugated diene polymer are shown
in the following Table 1.
Test Example
[0102] Analysis of conjugated diene polymers prepared in Example 1
to 3 and Comparative Examples 1 to 2 was performed in accordance
with the following method.
[0103] a) Mooney viscosity: measured at 100.degree. C. for 4
minutes using MV-2000 produced by ALPHA Technologies and two
specimens having a weight of 15 g or more after pre-heating for one
minute.
[0104] b) Gel permeation chromatography (GPC): GPC analysis was
performed at 40.degree. C. to determine molecular weight and
molecular weight distribution of the obtained polymer. The column
herein used was a combination of two PLgel Olexis columns produced
by Polymer Laboratories and one PLgel mixed-C column. All newly
replaced columns were mixed bed-type columns. In addition,
polystyrene (PS) was used as a GPC standard material for
determination of molecular weight. As a result of analysis, number
average molecular weight (Mn), weight average molecular weight (Mw)
and polydispersity were determined.
TABLE-US-00001 TABLE 1 Examples Comparative Examples Items 1 2 3 1
2 Sample A B C D E n-butyllithium (mmol) 4 4 4 4- 4 Polar additive
(g) 0.8 0.8 0.8 0.8 0.8 Modifying agent a* 5 3 -- -- -- (mmol) b*
-- -- 5 -- -- Coupling agent c -- -- -- -- 1.2 TDAE oil Phr -- --
-- 37.5 -- Mooney viscosity (MV) 62 68 60 61 64 NMR (%) SM 26 26 26
26 27 Vinyl 42 43 42 49 43 GPC (.times.10.sup.4) Mn 30 29 30 47 31
Mw 38 43 37 98 39 PDI 1.3 1.5 1.2 2.1 1.2 Note) a:
3-dimethylamino-2-((dimethylaminomethyl)propyl)trimethoxysilane b:
3-dimethylamino-2-((dimethylaminomethyl)propyl)triethoxysilane c:
dimethyldichlorosilane NMR: Proton Nuclear Magnetic Resonance
(.sup.1H-NMR) SM: Styrene monomer Vinyl: 1,3-butadiene as vinyl
monomer
TABLE-US-00002 TABLE 2 (Unit: parts by weight) S-1 S-2 Rubber 100.0
137.5 Silica 70.0 70.0 Coupling agent 11.02 11.2 Oil 33.75 -- Zinc
oxide 3.0 3.0 Stearic acid 2.0 2.0 Antioxidant 2.0 2.0 Anti-aging
agent 2.0 2.0 Wax 1.0 Rubber accelerator 1.75 1.75 Sulfur 1.5 1.5
Vulcanization accelerator 2.0 2.0 Total weight 230.2 234.0
[0105] Samples A, B and C shown in Table 1 as rubber raw materials
were mixed under mixing conditions shown in Table 2 above to
prepare conjugated diene polymer rubber compositions. The samples A
and C were mixed under mixing conditions of S-1 and the sample B
was mixed under mixing conditions of S-2.
[0106] Kneading of the rubber compositions of the conjugated diene
polymers will be described as follows. In primary kneading, a
rubber raw material (conjugated diene polymer), a filler, an
organosilane coupling agent, an oil, zinc oxide, a stearic acid
antioxidant, an anti-aging agent, a wax and accelerators were
kneaded at 80 rpm using a Banbury mixer equipped with a temperature
controller. At this time, the temperature of the kneader was
controlled and a primary mixture was obtained at a discharge
temperature of 140 to 150.degree. C. In secondary kneading, after
the primary mixture was cooled to room temperature, a rubber,
sulfur and a vulcanization accelerator were added to the kneader
and a secondary mixture was obtained at a discharge temperature of
45 to 60.degree. C. In tertiary kneading, the secondary mixture was
molded and was vulcanized using a vulcanization press at
180.degree. C. for T90+10 minutes to prepare vulcanized rubbers.
Physical properties of the prepared vulcanized rubbers were
measured in accordance with the following method.
[0107] 1) Tensile Strength Test
[0108] Tensile strength at break and tensile stress at an
elongation of 300% (300% modulus) of specimens were measured by
tensile strength testing in accordance with ASTM (American Society
for Testing and Materials) 412.
[0109] 2) Viscoelasticity
[0110] A dynamic mechanical analyzer produced by TA Instrument was
used. Tan .delta. was measured while changing strain in a torsional
mode at a frequency of 10 Hz and at different measurement
temperatures of 0 to 60.degree. C. Payne effect was represented as
a difference between a minimum and a maximum at a strain of 0.2% to
40%. As Payne effect decreases, dispersibility of a filler such as
silica is improved. As Tan .delta. at a low temperature of
0.degree. C. increases, wet skid resistance is improved, and as Tan
.delta. at a high temperature of 60.degree. C. decreases,
hysteresis loss decreases, and rolling resistance of tires
decreases, that is, fuel consumption thereof is reduced. Physical
properties of the vulcanized rubbers are shown in the following
Table 3.
TABLE-US-00003 TABLE 3 Items Comp. Comp. Ex. 4 Ex. 5 Ex. 6 Ex. 3
Ex. 4 Samples A B C D E 300% modulus 123 123 122 110 96
(Kgf/cm.sup.2) Tensile strength 189 192 188 191 174 (Kgf/cm.sup.2)
Tan .delta. at 0.degree. C. 0.883 0.881 0.851 0.791 0.497 Tan
.delta. at 60.degree. C. 0.062 0.064 0.066 0.085 0.096
.sup..DELTA.G' at 60.degree. C. 0.34 0.34 0.35 0.64 0.95 (Payne
effect)
[0111] As can be seen from results of Table 3 above, the modified
conjugated diene polymer rubber compositions according to Examples
4 to 6 exhibited a great increase in 300% modulus (tensile stress)
and a high Tan .delta. at 0.degree. C., as compared to Comparative
Examples 3 and 4, which indicates that tires comprising the
modified conjugated diene polymers exhibited great improvement of
wet skid resistance.
[0112] In addition, the modified conjugated diene polymers of
Examples 4 to 6 according to the present invention exhibited a low
Tan .delta. at 60.degree. C., as compared to Comparative Examples 3
and 4. Tires comprising the modified conjugated diene polymers
exhibited low rolling resistance as compared to the related
art.
[0113] In addition, the modified conjugated diene polymers
according to Examples 4 to 6 according to the present invention
exhibited a low Payne effect (AG') at 60.degree. C., as compared to
Comparative Examples 3 and 4. From this result, it could be seen
that dispersaiblity of silica was greatly improved.
* * * * *