DESCRIPTION
Method for Producing Polybutadiene
Technical Field
[0001]
The present invention relates to a method for producing
a reinforced polybutadiene of reduced odor (hereinafter
abbreviated as VCR) comprising a cis-1,4 polymer and a
syndiotactic-1,2 polymer, by polymerizing 1,3-butadiene.
Background Art
[0002]
As the method for production of VCR, there is known, in
JP-B-1974-17666 (patent Literature 1) and JP-B-1974-17667
(Patent Literature 2), a method which comprises subjecting
1,3-butadiene to cis-1,4 polymerization in an inert organic
solvent using a catalyst obtained from water, a soluble
cobalt compound and an organic aluminum chloride represented
by the general formula AlRnX3-n and then, in the
polymerization system, subjecting 1,3-butadiene to
syndiotactic-1,2 polymerization in the presence of a
syndiotactic-1,2 polymerization catalyst obtained from a
soluble cobalt compound, an organic aluminum compound
represented by the general formula AIR3 and carbon disulfide.
[0003]
Also, as the method for production of VCR, there is
described, in JP-B-1987-171 (Patent Literature 3), JP-B-1988-
36324 (Patent Literature 4), JP-B-1990-37927 (Patent
Literature 5), JP-B-1990-38081 (Patent Literature 6) and

JP-B-1991-63566 (Patent Literature 7), for example, a method
which comprises subjecting 1,3-butadiene to cis-1,4
polymerization in the presence or absence of carbon disulfide
to produce a VCR, or, after production of the VCR, separating
1,3-butadiene from carbon disulfide for recovery and
circulating 1,3-butadiene containing substantially no carbon
disulfide and an inert organic solvent. Further, in JP-B-
1992-48815 (Patent Literature 8), there is described a VCR
which is small in die swell ratio when made into a compound
and, when the compound has been vulcanized, is excellent in
tensile stress and flex-cracking resistance and is suitable
as a side wall of tire.
[0004]
In JP-A-2000-44633 (Patent Literature 9), there is
provided a method for producing a novel VCR, which comprises
subjecting 1,3-butadiene to cis-1,4 polymerization in an
inert organic solvent composed mainly of a C4 fraction, using
a catalyst system comprising a halogen-containing organic
aluminum compound, a soluble cobalt compound and water and,
in the resulting polymerization reaction mixture, subjecting
1,3-butadiene to syndiotactic-1,2 polymerization in the
presence of a syndiotactic-1,2 polymerization catalyst
obtained from a soluble cobalt compound, a trialkyl aluminum
compound and carbon disulfide. It is further disclosed that
the VCR obtained is a VCR composition comprising 3 to 30% by
weight of a boiling n-hexane-insoluble matter, which is a
syndiotactic-1,2-polybutadiene having a form of dispersed
short fiber crystals, and 97 to 70% by weight of a boiling n-
hexane-soluble matter, which has a cis structure containing
90% or more of a cis-1,4-polybutadiene.

[0005]
In JP-A-2000-154215 (Patent Literature 10) and JP-A-
2000-159836 (Patent Literature 11), there is provided a
method for producing a novel VCR, which comprises subjecting
1,3-butadiene to cis-1,4 polymerization using a catalyst
obtained from (A) a metallocene type complex of a transition
metal compound and (B) an ionic compound between non-
coordinating anion and cation and/or an aluminoxane and, in
the resulting polymerization reaction mixture, subjecting
1,3-butadiene to syndiotactic-1,2 polymerization in the
presence of a catalyst obtained from at least one compound
selected from (E) a cobalt compound, (F) an isocyanic acid
compound and carbon disulfide.
[0006]
In the syndiotactic-1,2 polymerization of 1,3-butadiene,
however, there are cases that offensive odor derived from the
sulfur compound used is generated depending upon the
polymerization conditions employed, and improvement has been
desired.
[0007]
In US Patent No. 6956093 (Patent Literature 12), there
is disclosed a method for producing a rubber composition of
reduced odor, which comprises treating, with hydrogen
peroxide, a syndiotactic-1,2-polybutadiene obtained by using
a catalyst containing carbon disulfide as a catalyst
component. However, the method is not preferred because the
hydrogen peroxide may oxidize the double bond of the
polybutadiene or the remaining butadiene monomer.
[0008]
Patent Literature 1: JP-B-1974-17666

Patent Literature 2: JP-B-1974-17667
Patent Literature 3: JP-B-1987-171
Patent Literature 4: JP-B-1988-36324
Patent Literature 5: JP-B-1990-37927
Patent Literature 6: JP-B-1990-38081
Patent Literature 7: JP-B-1991-63566
Patent Literature 8: JP-B-1992-48815
Patent Literature 9: JP-A-2000-44 633
Patent Literature 10: JP-A-2000-154215
Patent Literature 11: JP-B-2000-159836
Patent Literature 12: US Patent No. 6956093
Disclosure of the Invention
[0009]
The task to be achieved by the present invention is to
provide a method for producing a reinforced polybutadiene of
reduced odor (hereinafter, often abbreviated as VCR)
comprising a cis-1,4 polymer and a syndiotactic-1,2 polymer,
by polymerizing 1,3-butadiene.
[0010]
The present invention relates to a method for producing
a polybutadiene of reduced odor, which comprises subjecting
1,3-butadiene to cis-1,4 polymerization ,and subsequently
subjecting a resultant in the resulting polymerization system
to syndiotactic-1,2 polymerization, the method being
characterized in that there is added, after the
polymerization, a halogen acid or a halogen acid salt, both
represented by the following general formula (I):
M'(X'Oq)rZ's (1)
(wherein M' is a metal atom or a hydrogen atom; X' is a

halogen atom selected from chlorine, bromine and iodine; 0 is
an oxygen atom; q is an integer of 1 to 4; Z' is an anion
capable of bonding to M'; r is an integer of 1 or more; and
r+s is the oxidation number of M').
[0011]
In the present invention, the X' of the compound
represented by the general formula (I) is preferably chlorine.
[0012]
In the present invention, the compound represented by
the general formula (I) is preferably hypochlorous acid or a
hypochlorous acid salt.
[0013]
The present invention can be used as a method for
producing a reinforced polybutadiene rubber of reduced odor
by using a polybutadiene produced by the following method.
That is, firstly, a reinforced polybutadiene rubber of
reduced odor can be produced by using a polybutadiene
produced by using, as a catalyst for cis-1,4 polymerization,
a catalyst comprising a cobalt compound, an organic aluminum
compound and water. Secondly, a reinforced polybutadiene
rubber of reduced odor can be produced by using a
polybutadiene obtained by subjecting 1,3-butadiene to cis-1,4
polymerization using a catalyst obtained from a metallocene
type complex of a transition metal compound, and an ionic
compound between non-coordinating anion and cation and/or an
aluminoxane. Thirdly, a reinforced polybutadiene rubber of
reduced odor can be produced by using a polybutadiene
obtained by using, as a catalyst for cis-1,4 polymerization,
a catalyst obtained from (A) an yttrium compound, (B) an
ionic compound between non-coordinating anion and cation, and

(C) an organic metal compound of an element selected from
group 2, group 12 and group 13 of periodic table.
[0014]
In the method according to the present invention,
firstly, when there is used a polybutadiene produced by using,
as a catalyst for cis-1,4 polymerization, a catalyst
comprising a cobalt compound, an organic aluminum compound
and water, the organic aluminum compound is preferably a
trialkyl aluminum compound represented by R1^! (wherein R1 is
a hydrocarbon group having 1 to 10 carbon atoms) and a
halogen-containing aluminum compound represented by R23_nAlXn
(wherein R2 is a hydrocarbon group having 1 to 10 carbon
atoms, X is halogen, and n is a number of 1 to 2).
[0015]
It is also preferable that the catalyst for cis-1,4
polymerization is a catalyst obtained by subjecting, to aging,
components selected from a compound of a group 3 metal of
periodic table, an alkyl aluminum hydride compound, butadiene,
methyl aluminoxane and a chlorine-containing compound.
[0016]
Secondly, it is also preferable that the catalyst for
cis-1,4 polymerization is a catalyst obtained from a
metallocene type complex of a transition metal compound, an
ionic compound between non-coordinating anion and cation, an
organic metal compound of a group 1 to 3 element of periodic
table and water [(organic metal compound of group 1 to 3
element of periodic table)/(water) = 0.66 to 5 (molar ratio)].
[0017]
When there is used a catalyst containing an yttrium
compound, an yttrium compound having a bulky ligand,

represented by the following general formula:
[formula 1]

(wherein R1, R2 and R3 are each hydrogen or a hydrocarbon
group having 1 to 12 carbon atoms, 0 is an oxygen atom, and Y
is an yttrium atom)
[0018]
may be used preferably.
[0019]
Incidentally, the catalyst for the syndiotsactic-1,2
polymerization is preferably a cobalt compound, an alkyl
aluminum compound and a sulfur compound.
[0020]
The present invention also relates to a method for
producing a reinforced polybutadiene of reduced odor, wherein
the polybutadiene is a reinforced polybutadiene comprising
(1) 3 to 30% by weight of a boiling n-hexane-insoluble matter
and (2) 97 to 70% by weight of a boiling n-hexane-soluble
matter.
[0021]
The present invention provides a method for producing a
reinforced polybutadiene rubber of reduced odor, comprising a
cis-1,4 polymer and a syndiotactic-1,2 polymer, by adding a

halogen acid or a halogen acid salt after 1,3-butadine
polymerization.
Best Mode for carrying Out the Invention
[0022]
The present invention method for producing a
polybutadiene, which comprises subjecting 1,3-butadiene to
cis-1,4 polymerization ,and subsequently subjecting a
resultant in the resulting polymerization system to
syndiotactic-1,2 polymerization, the substance added, after
the polymerization, for odor reduction is a halogen acid or a
halogen acid salt, both represented by the following general
formula (I):
M'(X'Oq)rZ's (i)
(wherein M' is a metal atom or a hydrogen atom; X' is a
halogen atom selected from chlorine, bromine and iodine; 0 is
an oxygen atom; q is an integer of 1 to 4; Z' is an anion
capable of bonding to M'; r is an integer of 1 or more; and
r+s is the oxidation number of M' ) . As M' , there can be
mentioned, hydrogen, lithium, sodium, potassium, magnesium,
calcium, strontium, barium, yttrium, vanadium, iron, cobalt,
nickel, copper, zinc, boron, aluminum, etc. M' is preferably
hydrogen, lithium, sodium, potassium, magnesium, calcium or
aluminum; is particularly preferably hydrogen, sodium,
potassium, magnesium or calcium; and is further preferably
sodium or calcium.
[0023]
As X', there can be mentioned chlorine, bromine and
iodine. Of these, chlorine is preferred.
[0024]

q is an integer of 1 to 4, preferably 1 or 2,
particularly preferably 1.
[0025]
Z' is an anion other than halogen acid ion and has no
particular restriction as long as it can bond so as to
neutralize the positive charge of M remaining without being
sufficiently neutralized with the halogen acid ion. There
can be mentioned, for example, halogen ion such as chlorine,
bromine, iodine or the like; hydroxide ion; oxide ion;
nitrous acid ion; nitric acid ion; sulfuric acid ion;
phosphorous acid ion; phosphoric acid ion; boric acid ion;
carboxylic acid ion; and alkoxy ion. Of these, particularly
preferred are chlorine ion and hydroxide ion.
[0026]
r is the number of halogen acid ion bonding to M' and
is a positive sum not exceeding the oxidation number of M'.
s is the number of Z bonding to M'. Therefore, r+s is the
oxidation number of M'.
[0027]
As specific examples of the halogen acid or the halogen
acid salt, there can be mentioned hypochlorous acid, chlorous
acid, chrolic acid, perchloric acid, hypobromous acid,
bromous acid, bromic acid, perbromic acid, hypoiodous acid,
iodous acid, iodic acid, periodic acid, lithium hypochlorite,
sodium hyprochlorite, magnesium hypochlorite, calcium
hypochlorite, calcium hypochlorite chloride, and calcium
hypochlorite hydroxide. Preferred are sodium hypochlorite,
calcium hypochlorite, calcium hypochlorite chloride, and
calcium hypochlorite hydroxide, and particularly preferred is
sodium hypochlorite.

[0028]
As the solvent used in the polybutadiene production of
the present invention, there can be mentioned hydrocarbon
solvents such as straight chain aliphatic hydrocarbon such as
n-hexane, butane, heptane or pentane; cyclic aliphatic
hydrocarbon such as cyclopentane or cyclohexane; C4 fraction
olefinic hydrocarbon such as 1-butene, cis-2-butene or trans-
2-butene; mineral spirit, solvent naphtha, kerosene and the
like; halogenated hydrocarbon solvents such as methylene
chloride and the like; and so forth. They can be used singly
or in admixture. Of them, a cyclohexane-containing solvent
is used preferably. A mixture between cyclohexane and C4
fraction (e.g. cis-2-butene or trans-2-butene) is used
particularly preferably.
[0029]
As the first catalyst for cis-1,4 polymerization, there
can be used a catalyst comprising a cobalt compound, an
organic aluminum compound and water. As the organic aluminum
compound, there can be used a mixture of a trialkyl aluminum
compound represented by R^Al (wherein R1 is a hydrocarbon
group having 1 to 10 carbon atoms) and a halogen-containing
aluminum compound represented by R23-nAlXn (wherein R2 is a
hydrocarbon group having 1 to 10 carbon atoms, X is halogen,
and n is a number of 1 to 2) .
[0030]
As the cobalt compound in the catalyst for cis-1,4
polymerization, a salt or a complex of cobalt is used
preferably. As particularly preferred cobalt compounds,
there can be mentioned cobalt salts such as cobalt chloride,
cobalt bromide, cobalt nitrate, cobalt octylate, cobalt

naphthenate, cobalt acetate, cobalt malonate and the like;
cobalt bisacetylacetonate and trisacetylacetonate; cobalt
ethyl acetoacetate; cobalt halide-triarylphosphine complex,
its trialkylphosphine complex, its organic base complex such
as its pyridine complex or its picoline complex, or its ethyl
alcohol complex; etc.
[0031]
As the trialkyl aluminum compound represented by RX3A1
(wherein R1 is a hydrocarbon group having 1 to 10 carbon
atoms, preferably 2 to 8 carbon atoms), there can be
mentioned triethyl aluminum, trimethyl aluminum, triisobutyl
aluminum, trihexyl aluminum, trioctyl aluminum, etc. Of
these, triethyl aluminum is preferred.
[0032]
As the halogen-containing aluminum compound represented
by R23_nAlXn (wherein R2 is a hydrocarbon group having 1 to 10
carbon atoms, preferably 2 to 8 carbon atoms, X is halogen,
and n is a number of 1 to 2), there can be mentioned dialkyl
aluminum halides such as dialkyl aluminum chloride, dialkyl
aluminum bromide and the like; alkyl aluminum sesquihalides
such as alkyl aluminum sesquichloride, alkyl aluminum
sesquibromide and the like; alkyl aluminum dihalides such as
alkyl aluminum dichloride, alkyl aluminum dibromide and the
like; etc. As specific compounds, there can be mentioned
diethyl aluminum monochloride, diethyl aluminum monobromide,
dibutyl aluminum monochloride, ethyl aluminum sesquichloride,
ethyl aluminum dichloride, dicyclohexyl aluminum monochloride,
diphenyl aluminum monochloride, etc. Of these, diethyl
aluminum monochloride is preferred.
[0033]

The amount of the cobalt compound used is ordinarily
1x10-7 to lxlO-4 mol, preferably lxlO-6 to lxlO-5 mol relative
to 1 mol of the butadiene used.
[0034]
The amount of the trialkyl aluminum used is ordinarily
10 to 5,000 mols, preferably 50 to 1,000 mols relative to 1
mol of the cobalt compound used.
[0035]
The amount of the halogen-containing aluminum compound
used is 0 to 1, preferably 0.1 to 0.9, particularly
preferably 0.25 to 0.75 in terms of the ratio (X/Al) of the X
atom in the halogen-containing aluminum compound and the Al
atom in the trialkyl aluminum and the halogen-containing
aluminum.
[0036]
The amount of the water used is 0.1 to 1.45 mols,
preferably 0.2 to 1.2 mols relative to 1 mol of the aluminum
compound.
[0037]
As to the addition order of the catalyst components,
there is no particular restriction. However, it is preferred
that the trialkyl aluminum and the halogen-containing
aluminum are mixed and aged in an inert solvent and then used.
The aging time is preferably 0.1 to 24 hours, and the aging
temperature is preferably 0 to 80°C.
[0038]
It is preferred that water is added to the mixture
after aging, followed by further aging. The aging time is
preferably 0.1 to 24 hours, and the aging temperature is
preferably 0 to 80°C.

[0039]
As the catalyst for cis-1,4 polymerization, there may
also be used a catalyst obtained by subjecting, to aging,
components selected from a compound of a group 3 metal of
periodic table, an alkyl aluminum halide compound, butadiene,
methyl aluminoxane and a chlorine-containing compound.
[0040]
The metal constituting the compound of a group 3 metal
of periodic table which is a component of the above catalyst
system, is an atom belonging to the group 3 of periodic table,
and includes elements of lanthanum series, elements of
actinium series, etc. A rare earth metal is preferred.
Specifically, there is mentioned neodymium, praseodymium,
cerium, lanthanum, gadolinium, or a mixture thereof.
Neodymium is preferred particularly.
[0041]
As the compound of a group 3 metal of periodic table,
there can be mentioned a carboxylate of a group 3 metal of
periodic table, its alkoxide, its j3-diketone complex, its
phosphate or its phosphite, etc. Of these, a carboxylate and
a phosphate are preferred, and a carboxylate is preferred
particularly.
[0042]
The carboxylate of a group 3 metal of periodic table is
a compound represented by the general formula (RC02)3M
(wherein M is a group 3 metal of periodic table, and R is a
hydrocarbon group of 1 to 20 carbon atoms).
[0043]
The R is a saturated or unsaturated alkyl group which
is straight chain, branched chain or cyclic. The carboxyl

group C02 bonds to a primary, secondary or tertiary carbon
atom. Specifically, there can be mentioned salts of octanoic
acid, 2-ethyl-hexanoic acid, oleic acid, stearic acid,
benzoic acid, naphthenic acid, Versatic Acid (trade name of
Shell Chemical; a carboxylic acid in which carboxyl group
bonds to a tertiary carbon), etc. Of these, 2-ethyl-hexanoic
acid and Versatic Acid are preferred.
[0044]
The alkoxide of a group 3 metal of periodic table is a
compound represented by the general formula (RO)3M (wherein h
and R have the same definitions as give above) . As examples
of the alkoxy group represented by RO, there can be mentionec
2-ethyl-hexyloxy group, oleyloxy group, stearyloxy group,
phenoxy group and benzyloxy group. Of these, 2-ethyl-
hexyloxy group and benzyloxy group are preferred.
[0045]
As the /3-diketone complex of a group 3 metal of
periodic table, there can be mentioned, for example, a
complex of a group 3 metal of periodic table with
acetylacetone, benzoylacetone, propionitrileacetone,
valerylacetone, or ethyl acetoacetone. Of these,
acetylacetone complex and ethyl acetoacetone complex are
preferred.
[0046]
As the phosphate or phosphite of a group 3 metal of
periodic table, there can be mentioned bis(2-ethylhexyl)
phosphate of a group 3 metal of periodic table, its bis(l-
methylheptyl) phosphate, its bis(p-nonylphenyl) phosphate,
bis(polyethylene glycol-p-nonylphenyl) phosphate, its (1-
methylheptyl) (2-ethylhexyl) phosphate, its (2-ethylhexyl)

(p-nonylphenyl) phosphate, its mono-2-ethylhexyl 2-ethylhexyl
phosphonate, its mono-2-nonylphenyl 2-ethylhexyl phosphonate,
its bis(2-ethylhexyl) phosphinate, its bis(1-methylheptyl)
phosphinate, its bis(p-nonylphenyl) phosphinate, its (1-
methylheptyl) (2-ethylhexyl) phosphinate, its (2-ethylhexyl)
(p-nonylphenyl) phosphinate, etc. Of these, preferred are
bis(2-ethylhexyl) phosphate of a group 3 metal of periodic
table, its bis(1-methylheptyl) phosphate, its mono-2-
ethylhexyl 2-ethylhexyl phosphonate, its bis(2-ethylhexyl)
phosphinate, etc.
[0047]
Of the above-shown compounds, particularly preferred is
a phosphate of neodymium or a carboxylate of neodymium, and
most preferred are carboxylic acid salts, for example, 2-
ethyl hexanoic acid salt of neodymium and Versatic Acid salt
of neodymium.
[0048]
As the alkyl aluminum hydride compound of the above
catalyst system, there can be mentioned diethyl aluminum
hydride, dipropyl aluminum hydride, di-n-butylethyl aluminum
hydride, diisobutyl aluminum hydride, diphenyl aluminum
hydride, etc.
[0049]
As the chlorine-containing compound of the above
catalyst system, an alkyl aluminum chloride can be mentioned.
Particularly, there can be mentioned a dialkyl aluminum
halide such as dialkyl aluminum chloride, dialkyl aluminum
bromide or the like; an alkyl aluminum sesquihalide such as
alkyl aluminum sesquichloride, alkyl aluminum sesquibromide
or the like; an alkyl aluminum dihalide such as alkyl

aluminum dichloride, alkyl aluminum dibromide or the like;
etc. As specific compounds, there can be mentioned diethyl
aluminum monochloride, diethyl aluminum monobromide, dibutyl
aluminum monochloride, ethyl aluminum sesquichloride, ethyl
aluminum dichloride, dichlorohexyl aluminum monochloride,
diphenyl aluminum monochloride, etc.
[0050]
The proportions of the individual components of the
above catalyst system are preferably as follows.
(Alkyl aluminum hydride compound) : (compound of group 3
metal of periodic table) = 1:1 to 100:1 (molar ratio)
(Butadiene) : (compound of group 3 metal of periodic table) =
0.5:1 to 200:1 (molar ratio)
(Methyl aluminoxane) : (compound of group 3 metal of periodic
table) = 1:1 to 1000:1 (molar ratio)
(Chlorine-containing compound) : (compound of group 3 metal
of periodic table) = 1:1 to 10:1 (molar ratio)
[0051]
The above catalyst system is preferably used after
being subjected to aging. The aging time is preferably 1
minute to 150 minutes. The aging temperature is preferably
-10°C to 60°C.
[0052]
As the second catalyst for cis-1,4 polymerization,
there can be used a catalyst obtained from (a) a metallocene
type complex of a transition metal compound, and (b) an ionic
compound between non-coordinating anion and cation and/or an
aluminoxane, or a catalyst obtained from (a) a metallocene
type complex of a transition metal compound, (b) an ionic
compound between non-coordinating anion and cation, (c) an

organic metal compound of a group 1 to 3 element of periodic
table, and (d) water [(c)/(d) = 0.65 to 5 (molar ratio)].
[0053]
As the metallocene type complex of a transition metal
compound, which is a component (a), a metallocene type
complex of a compound of a group 4 to 8 transition metal of
periodic table can be mentioned.
[0054]
There can be mentioned, for example, a metallocene type
complex (e.g. CpTiCl3) of periodic table group 4 transition
metal such as titanium or zirconium; a metallocene type
complex of periodic table group 5 transition metal such as
vanadium, niobium or tantalum; a metallocene type complex of
periodic table group 6 transition metal such as chromium; and
a metallocene type complex of periodic table group 8
transition metal such as cobalt or nickel.
[0055]
Of them, a metallocene type complex of periodic table
group 5 transition metal is used preferably.
[0056]
As the metallocene type complex of periodic table group
5 transition metal, there can be mentioned compounds
represented by the following general formulas:
(1) RM-La
(2) RnMX2-n-La
(3) RnMX3-n-La
(4) RMX3-La
(5) RM(0)X2-La
(6) RnMX3-n(NR')
(wherein n 1 or 2 and a is 0, 1 or 2).

[0057]
Of them, RM-La, RMX3-La, RM(0)X2-La, etc. can be
mentioned preferably.
[0058]
M is preferably a compound of a periodic table group 5
transition metal. M is specifically vanadium (V), niobium
(Nb) or tantalum (Ta) with vanadium being preferred.
[0059]
R is cyclopentadienyl group, substituted
cyclopentadienyl group, indenyl group, substituted indenyl
group, fluorenyl group or substituted fluorenyl group.
[0060]
As the substituent in the substituted cyclopentadienyl
group, the substituted indenyl group, or the substituted
fluorenyl group, there can be mentioned, for example,
straight chain or branched chain aliphatic hydrocarbon groups
such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl,
sec-butyl, tert-butyl, hexyl and the like; aromatic
hydrocarbon groups such as phenyl, tolyl, naphthyl, benzyl
and the like; and silicon atom-containing hydrocarbon groups
such as trimethylsilyl and the like. There are further
included those groups in which cyclopentadienyl ring is
bonded to part of X via a crosslinking group such as
dimethylsilyl, dimethylmethylene, methylphenylmethylene,
diphenylmethylene, ethylene, substituted ethylene or the like.
[0061]
As specific examples of the substituted
cyclopentadienyl group, there can be mentioned
methylcyclopentadienyl group, 1,2-dimethylcyclopentadienyl
group, 1,3-dimethylcyclopentadienyl group, l,3-di(tert-

butyl)cyclopentadienyl group, and 1,2,3-
trimethylcyclopentadienyl group.
[0062]
X is hydrogen, halogen, hydrocarbon group having 1 to
20 carbon atoms, alkoxy group or amino group. All X's may be
the same or different from each other.
[0063]
As X, preferred are hydrogen, fluorine atom, chlorine
atom, bromine atom, methyl, ethyl, butyl, methoxy, ethoxy,
dimethylamino, diethylamino, etc.
[0064]
L is a Lewis base and is an ordinary inorganic or
organic compound of Lewis base type which can be coordinated
to a metal. A compound having no active hydrogen is
preferred particularly. As specific examples, there can be
mentioned ether, ester, ketone, amine, phosphine, silyloxy
compound, olefin, diene, aromatic compound and alkyne.
[0065]
NR' is imide group. R/ is a hydrocarbon group having 1
to 25 carbon atoms.
[0066]
As the component (a), i.e. the metallocene type complex
of a periodic table group 5 transition metal compound, there
is preferred one in which M is vanadium, i.e. a vanadium
compound. There are preferred, for example, RV*La, RVX-La,
R2V-La, RVX2-La, R2VX-La, RVX3-La, and RV(0)X2-La. RV-La and
RVX3-La are preferred particularly.
[0067]
As RM-La, i.e. the compound of a periodic table group 5
transition metal of +1 oxidation number, having one

cycloalkadienyl group as the ligand, there can be mentioned
cyclopentadienyl (benzene) vanadium, cyclopentadienyl
(toluene) vanadium, cyclopentadienyl (xylene) vanadium,
cyclopentadienyl (trimethylbenzene) vanadium,
cyclopentadienyl (hexamethylbenzene) vanadium,
cyclopentadienyl (ferrocene) vanadium, methylcyclopentadienyl
(benzene) vanadium, etc.
[0068]
The compound represented by RnMX2-n-La, when n is 1,
that is, the compound has one cycloalkadienyl group as the
ligand, the compound can have, as other, a-bond-formable
ligand, hydrogen; halogen atom such as chlorine, bromine,
iodine or the like; hydrocarbon group such as methyl group,
phenyl group, benzyl group, neopentyl group, trimethylsilyl
group, bistrimethylsilylmethyl group or the like; hydrocarbon
oxy group such as methoxy group, ethoxy group, isopropoxy
group or the like; and hydrocarbon amino group such as
dimethylamino group, diethylamino group, diisopropylamino
group, dioctylamino group or the like.
[0069]
The compound may further have, as other ligand, a
neutral Lewis base such as amine, amide, phosphine, ether,
ketone, ester, olefin, diene, aromatic hydrocarbon, alkyne or
the like. A Lewis base having no active hydrogen is
preferred.
[0070]
The compound represented by RnMX2-n*La, when n is 2,
that is, the compound has two cycloalkadienyl groups as the
ligand, the compound includes those compounds in which the
two cycloalkadienyl rings are bonded to each other via a

crosslinking group such as Me2Si group, dimethylethylene
group, methylphenylmethylene group, diphenylmethylene group,
ethylene group, substituted ethylene group or the like.
[0071]
As specific examples of the compound represented by
RnMX2-n-La in which n = 1, that is, the compound of a
periodic table group 5 transition metal of +2 oxidation
number, having one cycloalkadienyl group as the ligand, there
can be mentioned chlorocyclopentadienyl (tetrahydrofuran)
vanadium, chlorocyclopentadienyl (trimethylphosphine)
vanadium, and chlorocyclopentadienyl bis(trimethylphosphine)
vanadium.
[0072]
As specific examples of the compound represented by
RnMX2-n*La in which n = 2, that is, the compound of a
periodic table group 5 transition metal of +2 oxidation
number, having two cycloalkadienyl groups as the ligand,
there can be mentioned biscyclopentadienyl vanadium,
bis(methylcyclopentadienyl) vanadium,
bis(1,2-dimethylcyclopentadienyl) vanadium, and
bis(1,3-dimethylcyclopentadienyl) vanadium.
[0073]
As specific examples of the compound represented by
RnMX3-n*La in which n = 1, there can be mentioned
cyclopentadienyl vanadium dichloride, methylcyclopentadienyl
vanadium dichloride, (1,3-dimethylcyclopentadienyl) vanadium
dichloride, and (l-butyl-3-methylcyclopentadienyl) vanadium
dichloride. As specific examples of the compound represented
by RnMX3-n-La in which n = 2, there can be mentioned
dicyclopentadienyl vanadium chloride and

bis(methylcyclopentadienyl) vanadium chloride.
[0074]
As specific examples of the compound represented by
RMX3, the following compounds can be mentioned.
[0075]
(i) Cyclopentadienyl vanadium trichloride can be mentioned.
There can be mentioned mono-substituted cyclopentadienyl
vanadium trichlorides, for example, methylcyclopentadienyl
vanadium trichloride, ethylcyclopentadienyl vanadium
trichloride, and propylcyclopentadienyl vanadium trichloride.
[0076]
(ii) There can be mentioned 1,2-di-substituted
cyclopentadienyl vanadium trichlorides, for example,
(1,2-dimethylcyclopentadienyl) vanadium trichloride,
(l-ethyl-2-methylcyclopentadienyl) vanadium trichloride,
(l-methyl-2-propylcyclopentadienyl) vanadium trichloride,
(l-butyl-2-methylcyclopentadienyl) vanadium trichloride, and
(l-methyl-2-(bis(trimethylsilyl)methylcyclopentadienyl)
vanadium trichloride.
[0077]
(iii) There can be mentioned 1,2,3-tri-substituted
cyclopentadienyl vanadium trichlorides, for example,
(1,2,3-trimethylcyclopentadienyl) vanadium trichloride.
[0078]
As specific examples of the compound represented by
RM(0)X2, there can be mentioned cyclopentadienyl oxovanadium
dichloride, and methylcyclopentadienyl oxovanadium dichloride.
There can also be mentioned methyl-substituted compounds
obtained by substituting the chlorine atom of each of the
above compounds with methyl group.

[0079]
There can be mentioned cyclopentadienyl oxovanadium
dimethoxide, cyclopentadienyl oxovanadium di-isopropoxide,
cyclopentadienyl oxovanadium di-tert-butoxide,
cyclopentadienyl oxovanadium diphenoxide, cyclopentadienyl
oxovanadium methoxy chloride, cyclopentadienyl oxovanadium
isopropoxy chloride, cyclopentadienyl oxovanadium tert-butoxy
chloride, cyclopentadienyl oxovanadium phenoxy chloride, etc.
There can also be mentioned methyl-substituted compounds
obtained by substituting the chlorine atom of each of the
above compounds with methyl group.
[0080]
As a specific example of the compound represented by
RnMX3-n(NR/ ), cyclopentadienyl (methylimide) vanadium
dichloride can be mentioned.
[0081]
As the non-coordinating anion which constitutes the
component (b), i.e. the ionic compound between
non-coordinating anion and cation, there can be mentioned,
for example, tetra(phenyl) borate, tetra(fluorophenyl) borate,
tetrakis(difluorophenyl) borate, tetrakis(trifluorophenyl)
borate, tetrakis(tetrafluorophenyl) borate,
tetrakis(pentafluorophenyl) borate, and tetrakis(3,5-
bistrifluoromethylphenyl) borate.
[0082]
Meanwhile, as the cation, there can be mentioned
carbonium cation, oxonium cation, ammonium cation,
phosphonium cation, cycloheptatrienyl cation, transition
metal-containing cation such as ferrocenium, etc.
[0083]

As specific examples of the carbonium cation, there can
be mentioned tri-substituted carbonium cations such as
triphenyl carbonium cation, tris(substituted phenyl)
carbonium cation and the like. As specific examples of the
tris(substituted phenyl) carbonium cation, there can be
mentioned tri(methylphenyl) carbonium cation, and
tris(dimethylphenyl) carbonium cation.
[0084]
As specific examples of the ammonium cation, there can
be mentioned trialkyl ammonium cations such as trimethyl
ammonium cation, triethyl ammonium cation, tripropyl ammonium
cation, tributyl ammonium cation, tri(n-butyl) ammonium
cation and the like; and N,N-dimethyl anilinium cation.
[0085]
As specific examples of the phosphonium cation, there
can be mentioned triaryl phosphonium cations such as
triphenyl phosphonium cation, tri(methylphenyl) phosphonium
cation, tri(dimethylphenyl) phosphonium cation and the like.
[0086]
As the ionic compound, there can be preferably used any
combination of one of the above-shown non-coordinating anions
and one of the above-shown cations.
[0087]
Preferable as the ionic compound are triphenyl
carbonium tetrakis(pentafluorophenyl) borate, triphenyl
carbonium tetrakis(fluorophenyl) borate, N,N-dimethyl
anilinium tetrakis(pentafluorophenyl) borate, 1,1'-dimethyl
ferrocenium tetrakis(pentafluorophenyl) borate, etc.
[0088]
The ionic compound may be used singly or in combination

of two or more kinds.
[0089]
An aluminoxane may be selected as the component (b).
The aluminoxane is obtained by contacting an organic aluminum
compound with a condensation agent. There can be mentioned a
chain type aluminoxane or a cyclic aluminoxane, both
represented by the general formula (-A1(R')0-)n wherein R' is
a hydrocarbon group having 1 to 10 carbon atoms and may be
partly substituted with halogen atom and/or alkoxy group, n
is a polymerization degree and is 5 or more, preferably 10 or
more. As R', there can be mentioned methyl group, ethyl
group, propyl group and isobutyl group, with methyl group and
ethyl group being preferred. As the organic aluminum
compound used as a raw material of the aluminoxane, there can
be mentioned, for example, trialkyl aluminums such as
trimethyl aluminum, triethyl aluminum, triisobutyl aluminum
and the like; and mixtures thereof.
[0090]
An aluminoxane obtained by using, as a raw material, a
mixture of trimethyl aluminum and tributyl aluminum can be
used preferably.
[0091]
With respect to the condensation agent, water can be
mentioned as a typical condensation agent. Besides, there
can be mentioned any condensation agent with which the
trialkyl aluminum can give rise to a condensation reaction,
for example, adsorbed water of an inorganic compound and the
like, and a diol.
[0092]
An organic metal compound of a group 1 to 3 element of

periodic table may be added as the component (c). There can
be mentioned, for example, an organic aluminum compound, an
organic lithium compound, an organic magnesium compound, an
organic zinc compound, and an organic boron compound.
[0093]
As specific compounds, there can be mentioned methyl
lithium, butyl lithium, phenyl lithium, benzyl lithium,
neopentyl lithium, bistrimethylsilylmethyl lithium, dibutyl
magnesium, dihexyl magnesium, diethyl zinc, trimethyl
aluminum, etc.
[0094]
The component (c) further includes organic metal halide
compounds such as ethyl magnesium chloride, butyl magnesium
chloride, dimethyl aluminum chloride, diethyl aluminum
chloride, sesquiethyl aluminum chloride, ethyl aluminum
dichloride and the like; and organic metal hydride compounds
such as diethyl aluminum hydride, sesquiethyl aluminum
hydride and the like.
[0095]
An organic aluminum compound is preferred as the
component (c), i.e. the organic metal compound of periodic
table group 1 to 3 element. Specific examples of the organic
aluminum compound was mentioned above and includes trialkyl
aluminums such as trimethyl aluminum, triethyl aluminum,
triisobutyl aluminum and the like; organic aluminum halide
compounds such as dimethyl aluminum chloride, diethyl
aluminum chloride, sesquiethyl aluminum chloride, ethyl
aluminum dichloride and the like; and organic aluminum
hydride compounds such as diethyl aluminum hydride,
sesquiethyl aluminum hydride and the like. The above-

mentioned aluminoxane may be used. The above organic metal
compound may be used in combination of two or more kinds.
[0096]
The molar ratio of the component (a), i.e. the
metallocene type complex and the component (b), i.e. the
ionic compound is preferably 1:0.1 to 1:10, more preferably
1:0.2 to 1:5.
[0097]
The molar ratio of the component (a), i.e. the
metallocene type complex and the component (c), i.e. the
organic metal compound is preferably 1:0.1 to 1:1000, more
preferably 1:10 to 1:1000, further preferably 1:10 to 1:500.
[0098]
Preferably, water is added as a component (d) to the
above-mentioned catalyst components. The molar ratio of the
component (c), i.e. the organic metal compound and the
component (d), i.e. water is preferably 0.66 :5, more
preferably 0.7 to 1.5, further preferably 0.8 to 1.5.
[0099]
The addition order of the above catalyst components has
no particular restriction. However, the addition can be
conducted, for example, in the following order. The
component (d) is added to a conjugated diene compound monomer
to be polymerized or to a mixture of the monomer and a
solvent; the component (c) is added; then, the component (a)
and the component (b) are added in any desired order. Or,
the component (d) and the component (c) are added to a
conjugated diene compound monomer to be polymerized or to a
mixture of the monomer and a solvent; then, the component (a)
and the component (b) are added in any desired order.

[0100]
Here, the conjugated diene compound monomer to be
polymerized may be the total amount or part thereof. In the
case of the part of the monomer, the above contact mixture
can be mixed with the remaining monomer or the remaining
monomer solution.
[0101]
In the first-step polymerization, the molecular weight
of resulting polymer is controlled by polymerizing a
conjugated diene compound using the above catalyst preferably
in the presence of hydrogen.
[0102]
The amount of the hydrogen present is preferably 500
mmol or less, or 12 liters or less at 20°C at 1 atm. relative
to 1 mol of the conjugated diene; more preferably 50 mmols or
less, or 1.2 liters or less at 20°C at 1 atm., further
preferably 0.005 to 20 mmol, or 0.00001 to 0.48 liters at
20°C at 1 atm. Or, hydrogen may be introduced continuously
into the polymerization tank.
[0103]
The polymerization temperature is preferably -100 to
120°C, particularly preferably -50 to 100°C. The
polymerization time is 10 minutes to 12 hours, particularly
preferably 30 minutes to 6 hours. In order to further
suppress the formation of gel during the polymerization, a
known gelation inhibitor may be used.
[0104]
The use of the second catalyst system allows for
production of a polybutadiene having an intrinsic viscosity
of 0.1 to 20 as measured at 30°C in toluene. In this case, a

matrix polybutadiene can be produced which has a weight-
average molecular weight of 10,000 to 4,000,000 as determined
from GPC using a polystyrene as a standard substance and a
Mooney viscosity (ML1+4, 100°C, hereinafter abbreviated as
ML) of 10 to 130, preferably 15 to 80 and which has
substantially no gel content.
[0105]
As the third catalyst for cis-1,4 polymerization, there
can be used a catalyst obtained from (A) an yttrium compound,
(B) an ionic compound between non-coordinating anion and
cation, and (C) an organic metal compound of an element
selected from periodic table group 2, group 12 and group 13
elements.
[0106]
As the component (A), i.e. the yttrium compound of the
above catalyst system, an yttrium salt or an yttrium complex
is used preferably. As particularly preferred compounds,
there can be mentioned yttrium salts such as yttrium
trichloride, yttrium tribromide, yttrium triiodide, yttrium
nitrate, yttrium sulfate, yttrium trifluoromethanesulfonate,
yttrium acetate, yttrium trifluoroacetate, yttrium malonate,
yttrium octylate (ethylhexanoate), yttrium naphthenate,
yttrium Versatate, yttrium neodecanoate and the like;
alkoxides such as yttrium trimethoxide, yttrium triethoxide,
yttrium triisopropoxide, yttrium tributoxide, yttrium
triphenoxide and the like; organic yttrium compounds such as
trisacetylacetonatoyttrium, tris(hexanedionato)yttrium,
tris(heptanedionato)yttrium,
tris(dimethylheptanedionato)yttrium,
tris(tetramethylheptanedionato)yttrium,

trisacetoacetatoyttrium, cyclopentadienyl yttrium dichloride,
dicyclopentadienyl yttrium chloride, tricyclopentadienyl
yttrium and the like; organic base complexes such as pyridine
complex of yttrium salt, picoline complex of yttrium salt and
the like; yttrium salt hydrates; alcohol complexes of yttrium
salts; etc.
[0107]
Also, the following yttrium compound can be used.
[0108]
[Formula 2]

(In the above, Ri, R2 and R3 are each hydrogen or a
hydrocarbon group having 1 to 12 carbon atoms, 0 is an oxygen
atom, and Y is an yttrium atom.)
[0109]
As specific examples of Ri, R2 and R3, there can be
mentioned hydrogen, methyl group, ethyl group, vinyl group,
n-propyl group, isopropyl group, 1-propenyl group, allyl
group, n-butyl group, sec-butyl group, isobutyl group, tert-
butyl group, n-pentyl group, 1-methylbutyl group, 2-
methylbutyl group, 3-methylbutyl group, 1,1-dimethylpropyl
group, 1,2-dimethylpropyl group, 2,2-dimethylpropyl group,

hexyl group, heptyl group, octyl group, nonyl group, decyl
group, undecyl group, dodecyl group, cyclohexyl group,
methylcyclohexyl group, ethylcyclohexyl group, phenyl group,
benzyl group, toluyl group and phenethyl group. There are
further included those groups in which any of the above-
mentioned groups is substituted, at any position, with
hydroxyl group, carboxyl group, carbomethoxy group,
carboethoxy group, amide group, amino group, alkoxy group,
phenoxy group or the like.
[0110]
As the yttrium compound, an yttrium salt or an yttrium
complex is preferably used. Particularly preferred yttrium
compounds are tris(acetylacetonato)yttrium,
tris(hexanedionato)yttrium, tris(heptanedionato)yttrium,
tris(dimethylheptanedionato)yttrium,
tris(trimethylheptanedionato)yttrium,
tris(tetramethylheptanedionato)yttrium,
tris(pentamethylheptanedionato)yttrium,
tris(hexamethylheptanedionato)yttrium,
trisacetoacetatoyttrium, etc.
[0111]
In the component (B), i.e. the ionic compound between
non-coordinating anion and cation, of the above catalyst
system, there can be mentioned, as the non-coordinating anion,
for example, tetra(phenyl) borate, tetra(fluorophenyl) borate,
tetrakis(difluorophenyl) borate, tetrakis(trifluorophenyl)
borate, tetrakis(tetrafluorophenyl) borate,
tetrakis(pentafluorophenyl) borate, tetrakis(3,5-
bistrifluoromethylphenyl) borate,
tetrakis(tetrafluoromethylphenyl) borate, tetra(toluyl)

borate, tetra(xylyl) borate, triphenyl (pentafluorophenyl)
borate, tris(pentafluorophenyl) (phenyl) borate,
tridecahydride-7,8-dicarbaundecaborate, tetrafluoroborate,
and hexafluorophosphate.
[0112]
Meanwhile, as the cation, there can be mentioned
carbonium cation, oxonium cation, ammonium cation,
phosphonium cation, cycloheptatrienyl cation, ferrocenium
cation, etc.
[0113]
As specific examples of the carbonium cation, there can
be mentioned tri-substituted carbonium cations such as
triphenyl carbonium cation, tri-substituted phenyl carbonium
cation and the like. As specific examples of the
tri-substituted phenyl carbonium cation, there can be
mentioned tri(methylphenyl) carbonium cation, and
tri(dimethylphenyl) carbonium cation.
[0114]
As specific examples of the ammonium cation, there can
be mentioned trialkyl ammonium cations such as trimethyl
ammonium cation, triethyl ammonium cation, tripropyl ammonium
cation, tributyl ammonium cation, tri(n-butyl) ammonium
cation and the like; N,N-dialkyl anilinium cations such as
N,N-dimethyl anilinium cation, N,N-diethyl anilinium cation,
N,N-2,4,6-pentamethyl anilinium cation and the like; and
dialkyl ammonium cations such as di(isopropyl) ammonium
cation, dicyclohexyl ammonium cation and the like.
[0115]
As specific examples of the phosphonium cation, there
can be mentioned aryl phosphonium cations such as triphenyl

phosphonium cation, tetraphenyl phosphonium cation,
tri(methylphenyl) phosphonium cation, tetra(methylphenyl)
phosphonium cation, tri(dimethylphenyl) phosphonium cation,
tetra(dimethylphenyl) phosphonium cation and the like.
[0116]
As the ionic compound, there can be preferably used any
combination of one of the above-shown non-coordinating anions
and one of the above-shown cations.
[0117]
Preferably as the ionic compound are triphenyl
carbonium tetrakis(pentafluorophenyl) borate, triphenyl
carbonium tetrakis(fluorophenyl) borate, N,N-dimethyl
anilinium tetrakis(pentafluorophenyl) borate, 1,1'-dimethyl
ferrocenium tetrakis(pentafluorophenyl) borate, etc. The
ionic compound may be used singly or in combination of two or
more kinds.
[0118]
An aluminoxane may be selected as the component (B).
The aluminoxane is obtained by contacting an organic aluminum
compound with a condensation agent. There can be mentioned a
chain type aluminoxane and a cyclic aluminoxane, both
represented by the general formula (-A1(R/)0-)n wherein R'
is a hydrocarbon group having 1 to 10 carbon atoms and may be
partly substituted with halogen atom and/or alkoxy group, n
is a polymerization degree and is 5 or more, preferably 10 or
more. As R', there can be mentioned methyl group, ethyl
group, propyl group and isobutyl group with methyl group
being preferred. As the organic aluminum compound used as a
raw material of the aluminoxane, there can be mentioned, for
example, trialkyl aluminums such as trimethyl aluminum,

triethyl aluminum, triisobutyl aluminum and the like; and
mixtures thereof.
[0119]
An aluminoxane obtained using, as a raw material, a
mixture of trimethyl aluminum and tributyl aluminum can be
used preferably.
[0120]
With respect to the condensation agent, water can be
mentioned as a typical condensation agent. Besides, there
can be mentioned any condensation agent with which the
trialkyl aluminum can give rise to a condensation reaction,
for example, adsorbed water of an inorganic compound and the
like, and a diol.
[0121]
As the component (C) of the above catalyst system, i.e.
the organic metal compound of a periodic table group 2, 12 or
13 element, there can be used, for example, an organic
magnesium, an organic zinc and an organic aluminum. Of these
compounds, preferred are dialkyl magnesium, alkyl magnesium
chloride, alkyl magnesium bromide, dialkyl zinc, trialkyl
aluminum, dialkyl aluminum chloride, dialkyl aluminum bromide,
alkyl aluminum sesquichloride, alkyl aluminum sesquibromide,
alkyl aluminum dichloride, dialkyl aluminum hydride, etc.
[0122]
As specific compounds, there can be mentioned alkyl
magnesium halides such as methyl magnesium chloride, ethyl
magnesium chloride, butyl magnesium chloride, hexyl magnesium
chloride, octyl magnesium chloride, ethyl magnesium bromide,
butyl magnesium bromide, butyl magnesium iodide, hexyl
magnesium iodide and the like.

[0123]
There can further be mentioned dialkyl magnesiums such
as dimethyl magnesium, diethyl magnesium, dibutyl magnesium,
dihexyl magnesium, dioctyl magnesium, ethyl butyl magnesium,
ethyl hexyl magnesium and the like.
[0124]
There can further be mentioned trialkyl zincs such as
dimethyl zinc, diethyl zinc, diisobutyl zinc, dihexyl zinc,
dioctyl zinc, didecyl zinc and the like.
[0125]
There can further be mentioned trialkyl aluminums such
as trimethyl aluminum, triethyl aluminum, triisobutyl
aluminum, trihexyl aluminum, trioctyl aluminum, tridecyl
aluminum and the like.
[0126]
There can further be mentioned organic aluminum halide
compounds such as dialkyl aluminum chloride such as dimethyl
aluminum chloride or diethyl aluminum chloride; ethyl
aluminum sesquichloride, ethyl aluminum dichloride and the
like; and organic aluminum hydride compounds such as diethyl
aluminum hydride, diisobutyl aluminum hydride, ethyl aluminum
sesquihydride and the like.
[0127]
These organic metal compounds of periodic table group 2,
12 or 13 element can be used singly or in combination of two
or more kinds.
[0128]
In the third method, there can be used, as a molecular
weight controller for the polybutadiene obtained, a compound
selected from (1) hydrogen, (2) a metal hydride compound and

(3) an organic metal hydride compound.
[0129]
As the metal hydride compound (2) used as a molecular
weight controller, there can be mentioned lithium hydride,
sodium hydride, potassium hydride, magnesium hydride, calcium
hydride, borane, aluminum hydride, gallium hydride, germane,
lithium boron hydride, sodium boron hydride, lithium aluminum
hydride, sodium aluminum hydride, etc.
[0130]
As the organic metal hydride compound (3) used as a
molecular weight controller, there can be mentioned, for
example, alkyl boranes such as methyl borane, ethyl borane,
propyl borane, butyl borane, phenyl borane and the like;
dialkyl boranes such as dimethyl borane, diethyl borane,
dipropyl borane, dibutyl borane, diphenyl borane and the
like; alkyl aluminum dihydrides such as methyl aluminum
dihydride, ethyl aluminum dihydride, propyl aluminum
dihydride, butyl aluminum dihydride, phenyl aluminum
dihydride and the like; dialkyl aluminum hydrides such as
dimethyl aluminum hydride, diethyl aluminum hydride, dipropyl
aluminum hydride, dibutyl aluminum hydride, diphenyl aluminum
hydride and the like; silanes such as methyl silane, ethyl
silane, propyl silane, butyl silane, phenyl silane, dimethyl
silane, diethyl silane, dipropyl silane, dibutyl silane,
diphenyl silane, trimethyl silane, triethyl silane, tripropyl
silane, tributyl silane, triphenyl silane and the like; and
germanes such as methyl germane, ethyl germane, propyl
germane, butyl germane, phenyl germane, dimethyl germane,
diethyl germane, dipropyl germane, dibutyl germane, diphenyl
germane, trimethyl germane, triethyl germane, tripropyl

germane, tributyl germane, triphenyl germane and the like.
[0131]
Of these, preferred are diisobutyl aluminum hydride and
diethyl aluminum hydride, and particularly preferred is
diethyl aluminum hydride.
[0132]
The addition order of the catalyst components has no
particular restriction; however, the addition can be made in
the following order.
[0133]
(1) The component (C) is added in an inert organic solvent in
the absence or presence of a butadiene monomer to be
polymerized, and the component (A) and the component (B) are
added in any desired order.
[0134]
(2) The component (C) is added in an inert organic solvent in
the absence or presence of a butadiene monomer to be
polymerized, the above-mentioned molecular weight controller
is added, and then the component (A) and the component (B)
are added in any desired order.
[0135]
(3) The component (A) is added in an inert organic solvent in
the absence or presence of a butadiene monomer to be
polymerized, the component (C) and the above-mentioned
molecular weight controller are added in any desired order,
and then the component (B) is added.
[0136]
(4) The component (B) is added in an inert organic solvent in
the absence or presence of a butadiene monomer to be
polymerized, the component (C) and the above-mentioned

molecular weight controller are added in any desired order,
and then the component (A) is added.
[0137]
(5) The component (C) is added in an inert organic solvent in
the absence or presence of a butadiene monomer to be
polymerized, the component (A) and the component (B) are
added in any desired order, and then the above-mentioned
molecular weight controller is added.
[0138]
The individual components may be subjected to aging,
before use. In particular, the component (A) and the
component (C) are preferred to be subjected to aging.
[0139]
With respect to the aging conditions, the component (A)
and the component (C) are mixed in an inert solvent in the
presence or absence of a butadiene monomer to be polymerized.
The aging temperature is -50 to 80°C, preferably -10 to 50°C,
and the aging time is 0.01 to 24 hours, preferably 0.05 to 5
hours, particularly preferably 0.1 to 1 hour.
[0140]
In the present invention, the individual catalyst
components may be used by being loaded on an inorganic
compound or an organic polymer compound.
[0141]
In the polybutadiene production with the first or
second catalyst as well, there can be used a known molecular
weight controller, for example, hydrogen, a non-conjugated
diene such as cyclooctadiene or allene; or an a-olefin such
as ethylene, propylene or butene-1.
[0142]

In the polybutadiene production with the first catalyst,
the polymerization temperature is preferably -30 to 100°C,
particularly preferably 30 to 80°C. The polymerization time
is preferably 10 minutes to 12 hours, particularly preferably
30 minutes to 6 hours. The polymerization is conducted at
normal pressure or at an applied pressure up to about 10 atm.
(gauge pressure). Cis-1,4 polymerization is preferably
conducted so that the polymer concentration after cis-1,4
polymerization becomes 5 to 26% by weight. With respect to
the polymerization tank, a single tank or two- or more-
connected tanks are used. The polymerization is conducted by
stirring a solution in a polymerization tank (polymerizer).
As the polymerization tank, there can be used a
polymerization tank with a stirrer for high-viscosity
solution, for example, an apparatus described in JP-B-1965-
2645.
[0143]
A known gelation inhibitor may be used in order to
further suppress gel formation during the polymerization.
The polybutadiene obtained has a cis-1,4-structure content of
ordinarily 90% or more, particularly 95% or more, a Mooney
viscosity (ML1+4, 100°C, hereinafter abbreviated as ML) of 10
to 130, preferably 15 to 80, and substantially no gel content.
[0144]
1,3-Butadiene may be added or may not be added to the
cis-1,4 polymerization reaction mixture obtained above. Then,
syndiotactic-1,2 polymerization is conducted in this
polymerization system.
[0145]
As to the polymerization method with the third catalyst,

there is no particular restriction, either. There can be
employed bulk polymerization using 1,3-butadiene per se as a
polymerization solvent, solution polymerization, etc. As the
solvent in the solution polymerization, there can be
mentioned aliphatic hydrocarbons such as butane, pentane,
hexane, heptane and the like; alicyclic hydrocarbons such as
cyclopentane, cyclohexane and the like; aromatic hydrocarbons
such as benzene, toluene, xylene, ethylbenzene and the like;
olefinic hydrocarbons such as the above-mentioned olefin
compounds, cis-2-butene, trans-2-butene and the like; and so
forth.
[0146]
Of them, preferably used are benzene, toluene,
cyclohexane, a mixture of cis-2-butene and trans-2-butene,
etc.
[0147]
The polymerization temperature is preferably -30 to
150°C, particularly preferably 30 to 100°C. The
polymerization time is preferably 1 minute to 12 hours,
particularly preferably 5 minutes to 5 hours.
[0148]
After the polymerization has been conducted for a given
length of time, the inside pressure of the polymerization
tank is released as necessary, and post-treatments such as
washing, drying and the like are conducted.
[0149]
As the thus-obtained polybutadiene, there can be
mentioned a cis-1,4-polybutadiene having a cis-1,4 structure
in an amount of preferably 90% or more, more preferably 92%
or more, particularly preferably 96% or more. The [ v ] of

the conjugated diene polymer can be controlled to preferably
0.1 to 10, more preferably 1 to 7, particularly preferably
1.5 to 5.
[0150]
The cis-1,4 polymerization is preferably conducted so
that the polymer concentration after cis-1,4 polymerization
becomes 5 to 26% by weight. With respect to the
polymerization tank, a single tank or two- or more-connected
tanks are used. The polymerization is conducted by stirring
a solution in a polymerization tank (polymerizer). As the
polymerization tank, there can be used a polymerization tank
with a stirrer for high-viscosity solution, for example, an
apparatus described in JP-B-1965-2645.
[0151]
A known gelation inhibitor may be used in order to
further suppress gel formation during the polymerization.
The polybutadiene obtained has a cis-1,4-structure content of
ordinarily 90% or more, particularly 95% or more and a Mooney
viscosity (ML) of 10 to 130, preferably 15 to 80, and
preferably has substantially no gel content.
[0152]
As the catalyst for syndiotactic-1,2 polymerization,
there is used a catalyst system comprising a trialkyl
aluminum compound represented by R13Al (wherein R1 is a
hydrocarbon group having 1 to 10 carbon atoms), a sulfur
compound and, as necessary, a cobalt compound.
[0153]
As the sulfur compound, there can be mentioned carbon
disulfide, phenyl isothiocyanate, a xanthogenic acid compound,
etc. Of them, carbon disulfide is preferred. As the

trialkyl aluminum compound represented by R13Al (wherein R1 is
a hydrocarbon group having 1 to 10 carbon atoms) and the
cobalt compound, there can be mentioned the above-mentioned
compounds used in the cis-1,4 polymerization.
[0154]
The trialkyl aluminum compound is used in an amount of
0.1 mmol or more, particularly 0.5 to 50 mmols or more
relative to 1 mol of 1,3-butadiene. The sulfur compound is
not restricted particularly but preferably contains no water.
The concentration of the sulfur compound is 20 mmols/L or
less, particularly preferably 0.01 to 10 mmols/L.
[0155]
The temperature of 1,2-polymerization of 1,3-butadiene
is 0°C to 100°C, preferably 10 to 100°C, more preferably 20 to
100°C. Into the polymerization system where the
1,2-polymerization is to be conducted, 1,3-butadiene can be
added in an amount of 1 to 50 parts by weight, preferably 1
to 20 parts by weight per 100 parts by weight of the cis
polymerization mixture, whereby the yield of
1,2-polybutadiene in 1,2-polymeirzation can be increased.
The polymerization time (average residence time) is
preferably 10 minutes to 2 hours. The 1,2-polymerization is
preferably conducted so that the polymer concentration after
1,2-polymeirzation becomes 9 to 29% by weight. With respect
to the polymerization tank, a single tank or two- or more-
connected tanks are used. The polymerization is conducted by
stirring a polymerization solution in a polymerization tank
(polymerizer) . As the polymerization tank used in the
1,2-polymerization, there can be used a polymerization tank
with a stirrer for high-viscosity solution, for example, an

apparatus described in JP-B-1965-2645, because the solution
viscosity becomes higher during the 1,2-polymerization and
polymer adhesion tends to occur.
[0156]
When, in the polymerization reaction, an intended
conversion has been achieved, the above-mentioned halogen
acid or halogen acid salt is added to terminate the
polymerization. The halogen acid or halogen acid salt is
added preferably in the form of a solution, particularly an
aqueous solution or an alcohol solution such as methanol or
ethanol solution. Further, a surfactant may be allowed to be
present in order to improve the dispersibility in the polymer
solution.
[0157]
The addition amount of the halogen acid or halogen acid
salt is 0.001 mol to 10 mols, preferably 0.002 to 5 mols,
more preferably 0.005 to 2 mols, relative to 1 mol of the
sulfur compound. The mixing time after the addition is 5
seconds to 1 hour, preferably 10 seconds to 30 minutes, more
preferably 20 seconds to 10 minutes.
[0158]
Further, a known anti-oxidant may be added according to
an ordinary method. As the anti-oxidant, there can be
mentioned 2,6-di-tert-butyl-p-cresol (BHT) as a phenol type,
trinonylphenyl phosphite (TNP) as a phosphorus type,
dilauryl-3,3'-thiodipropionate (TPL) as a sulfur type, etc.
The anti-oxidant may be used singly or in combination of two
or more kinds. The addition amount of the anti-oxidant is
0.001 to 5 parts by weight relative to 100 parts by weight of
VCR. Then, a short-stop is added to the polymerization

system to stop the polymerization. It is conducted according
to a per-se-known method, for example, a method of feeding,
after the completion of the polymerization reaction, the
polymerization solution into a polymerization termination
tank and adding thereto a large amount of a polar solvent
such as alcohol, e.g., methanol or ethanol, water or the
like, or a method of introducing, into the polymerization
solution, an inorganic acid such as hydrochloric acid or
sulfuric acid, an organic acid such as acetic acid or benzoic
acid, or hydrogen chloride gas. Then, the VCR formed is
separated, washed and dried according to ordinary methods.
[0159]
Incidentally, when, prior to the separation and
purification, the halogen acid or halogen acid salt remains
in the reaction system, the remaining halogen acid or halogen
acid salt is deactivated by contact with an aqueous solution
containing a reducing agent such as sulfurous acid, sulfurous
acid salt, thiosulfuric acid salt, nitrous acid salt, oxalic
acid, oxalic acid salt or the like. Thereby, the VCR
obtained can be prevented from oxidation.
[0160]
The prevention of VCR from oxidation can also be
achieved by adding, in order to prevent the oxidation by
remaining halogen acid or halogen acid salt, an effective
assistant, for example, an assistant (e.g. anti-oxidant)
ordinarily added to a rubber composition. As the
anti-oxidant, a known anti-oxidant such as hindered phenol or
the like can be used.
[0161]
The thus-obtained VCR is composed of (1) 3 to 30% by

weight of a boiling n-hexane-insoluble matter (H.I.) and (2)
97 to 70% by weight of a boiling n-hexane-soluble matter.
The boiling n-hexane-soluble matter is a cis-1,4-
polybutadiene having 80% or more of a micro structure. The
H.I. is an SPBD having a melting point of 180 to 215°C. The
VCR has an ML of 20 to 150, preferably 25 to 100 at 100°C.
In the VCR, the syndiotactic-1,2 polybutadiene is uniformly
dispersed in the cis-1,4-polybutadiene matrix as fine
crystals. The VCR is low in odor as compared with
conventional VCRs.
[0162]
The VCR obtained by the present invention is compounded
singly or by blending with other synthetic rubber or natural
rubber, is as necessary extended with a process oil, then is
mixed with a filler (e.g. carbon black), a vulcanizing agent,
a vulcanization accelerator and other ordinary compounding
agents, and is vulcanized. The resulting product is used in
rubber applications wherein mechanical properties and
abrasion resistance are required, such as tire (e.g. tread,
side wall, stiffner, bead filler, inner liner and carcas) and
various other industrial products (e.g. hose and belt). The
VCR can also be used as a modifier for plastic.
Examples
[0163]
In the following Examples and Comparative Examples,
each butadiene rubber was measured for the following items as
follows.
[0164]
Reduced viscosity of n-hexane-insoluble matter

25 g of a polybutadiene rubber was placed in 1,000 ml
of boiling n-hexane and the mixture was subjected to
refluxing, whereby the polybutadiene rubber was separated
into a boiling n-hexane-soluble matter and a boiling
n-hexane-insoluble mater. 0.2 g of the boiling n-hexane-
insoluble matter was dissolved in 100 ml of tetralin, and the
solution was measured for viscosity at 130°C using an
Ubbellohde viscometer.
Melting point of n-hexane insoluble matter
Measured from an endothermic curve by DSC.
[0165]
Measurement of weight-average molecular weight of n-hexane-
soluble matter
25 g of a polybutadiene rubber was placed in 1,000 ml
of boiling n-hexane and the mixture was subjected to
refluxing. The boiling n-hexane-insoluble matter was
separated by filtration to recover a n-hexane solution. From
the n-hexane solution was removed n-hexane to recover a
n-hexane-soluble matter. The n-hexane-soluble matter was
dissolved in tetrahydrofuran. The solution was subjected to
GPC to determine a molecular weight in terms of polystyrene,
and the Mw of n-hexane-soluble matter was calculated
therefrom. The measurement was conducted under the following
conditions.
Apparatus: HLC-8 02A Model (a product of Tosoh
Corporation); columns: GMH 6000, two in parallel: elutant:
tetrahydrofuran; elutant flow rate: 1.0 ml/min; measurement
temperature: column tank 40°C, detector 40°C; sample
concentration: 0.25 g/L; sample injection amount: 0.5 ml
[0166]

Micro-structure of n-hexane-soluble matter
The boiling n-hexane-soluble matter obtained as above
was subjected to infrared spectrometry and the micro-
structure of the boiling n-hexane-soluble matter was
calculated from the absorption intensity ratio of cis-1,4-
structure 740 cm-1, trans-1,4-structure 967 cm-1 and
1,2-structure (vinyl) 911 cm-1.
[0167]
Toluene solution viscosity (T-cp) of n-hexane-soluble matter
The boiling n-hexane-soluble matter obtained as above
was dissolved in toluene in a concentration of 5% by weight.
The viscosity of the solution was measured at 25°C using a
Cannon-Fenske viscometer.
[0168]
Mooney viscosity of n-hexane-soluble matter and compound
Measured in accordance with the method specified in JIS
K 6300.
[0169]
Inspection of residual odor
The product obtained was smelled to inspect the degree
of the residual odor. Further, since an odor substance is
present mainly in the volatile components of the product, the
amount of volatile components was employed as an indication
for objectively knowing the degree of odor. Therefore, the
amount of volatile components was measured under the
following conditions. The amount was compared with the level
of the odor obtained by organoleptic inspection and the level
of residual odor was judged comprehensively. Incidentally,
the measurement result of the amount of volatile components
was expressed as a relative value when the amount of volatile

components obtained in Comparative Example 1 was taken as 100,
and is shown in Table 1 which appears later.
[0170]
2.5 g of the rubber obtained in each Example was
weighed accurately in a 20-ml sample bottle and heated at
170°C for 30 minutes. Then, using 1 ml of the vapor portion
in the sample bottle, measurement was conducted using a gas
chromatograph provided with a FPD detector, under the
following conditions.
FPD gas chromatograph: Agilent 6890 model
Column model: HP-1, 60 m (length) x 0.32 mm (inner
diameter) x 5.0 urn (film thickness)
Column conditions: Keeping at 4 0°C for 5 minutes; then,
temperature elevation to 250°C at a
rate of 15°C per minute; lastly,
keeping at 250°C for 11 minutes.
Measurement time: 30 minutes
[0171]
(Example 1)
(Cis 1,4-polymerization)
The content of a 2.0-L (content volume) autoclave was
purged with nitrogen. Thereinto was injected 1 L of a
solution (FB) consisting of cyclohexane (350 ml), cis
2-butene (340 ml) and 1,3-butadiene (310 ml), followed by
stirring for 30 minutes. Then, 19 mg of carbon disulfide and
26 mg of water (H20) were added, followed by stirring for 30
minutes for dissolution. Then, diethyl aluminum chloride
(DEAC) was added so that the concentration became 2.9 mmols/L.
3 minutes later, 8 mg of dilauryl thiodipropionate and 1.45
ml of cyclooctadiene were added. The mixture was heated to

50°C. Then, 0.6 ml of cobalt octylate [Co(Oct)2] (a toluene
solution of 30 mg/ml) was added, and matrix polymerization
was conducted at a temperature of 50°C for 20 minutes.
(Syndiotactc-1,2 polymerization)
Next, triethyl aluminum (TEA) was added so that the
concentration became 3.5 mmols/L, followed by stirring for 5
minutes. Then, 0.6 ml of a toluene solution of cobalt
octylate (30 ml/L) was added and polymerization was conducted
for 20 minutes.
After the polymerization, 1.2 6 ml of an aqueous sodium
hypochlorite (0.05 mol/L) solution was added to stop the
polymerization reaction. Thereafter, the polymerization
mixture was treated according to an ordinary method to
recover a polybutadiene rubber.
The polybutadiene rubber obtained gave a yield of 95.7
g and showed a Mooney viscosity of 49.4 (ML1+4, 100°C) . The
rubber had substantially no odor in an organoleptic test.
[0172]
The rubber had 13% by weight of a boiling n-hexane-
insoluble matter and 87% by weight of a boiling n-hexane-
soluble matter. The n-hexane-insoluble mater showed a peak
of 201.3°C in the endothermic curve by DSC.
[0173]
(Example 2)
Polymerization was conducted in the same manner as in
Example 1 except that the addition amount of the aqueous
sodium hypochlorite solution was 3.72 ml. The polybutadiene
rubber obtained gave a yield of 99.2 g and showed a Mooney
viscosity of 48.9 (ML1+4, 100°C) . The rubber had
substantially no odor.

[0174]
The rubber had 13.5% by weight of a boiling n-hexane-
insoluble matter and 8 6.5% by weight of a boiling n-hexane-
soluble matter. The n-hexane-insoluble matter showed a peak
of 201.1°C in the endothermic curve by DSC.
[0175]
(Comparative Example 1)
Polymerization was conducted in the same manner as in
Example 1 except that, at the time of polymerization stop,
water was added in place of the aqueous sodium hypochlorite
solution. The polybutadiene rubber obtained gave a yield of
99.7 g and showed a Mooney viscosity of 48.5 (ML1+4, 100°C) .
The rubber had an offensive odor.
[0176]
The rubber had 12.9% by weight of a boiling n-hexane-
insoluble matter and 87.1% by weight of a boiling n-hexane-
soluble matter. The n-hexane-insoluble matter showed a peak
of 201.3°C in the endothermic curve by DSC.
[0177]
(Cis 1,4-polymerization)
(Example 3)
The content of a 1.5-L (content volume) autoclave was
purged with nitrogen. Thereinto was fed 700 ml of a mixed
solution of 33 wt. % of butadiene, 16 wt. % of cyclohexane
and 51 wt. % of 2-butene. Water (H20) was added at room
temperature so that the concentration became 3.7 mmols/L, and
carbon disulfide and 1,5-cyclooctadiene were added so that
the former's concentration became 30 mg/L and the latter's
concentration became 10.2 mmols/L. Vigorous stirring was
conducted at 700 rpm for 30 minutes. 2.4 ml of a cyclohexane

solution of diethyl aluminum chloride (DEAC) and triethyl
aluminum (TEA) [DEAC:TEA = 2:1 (molar ratio), Al
concentration = 1 ntol/L] was added, followed by stirring at
room temperature for 5 minutes. The mixture was heated to
60°C, and 1.8 ml of a toluene solution of cobalt octylate
[Co(Oct)2] (0.005 mol/L) was added. Polymerization was
initiated and continued at 70°C for 15 minutes.
(Syndiotactic-1,2 polymerization)
Then, 4.2 ml of a cyclohexane solution of triethyl
aluminum (TEA) (1 mol/L) were added thereto. Successively,
there were added 140 ml of 1,3-butadiene, 36 mg of water, and
1.05 ml of a toluene solution of cobalt octylate [Co(Oct)2]
(0.05 mol/L). Polymerization was conducted at 60°C for 15
minutes.
2 ml of an aqueous sodium hypochlorite (0.2 mol/L)
solution was added, followed by stirring for 5 minutes to
stop the polymerization reaction. Then, the polymerization
mixture was treated according to an ordinary method to
recover a polybutadiene rubber.
The polybutadiene rubber obtained gave a yield of 113 g
and showed a Mooney viscosity of 72 (ML1+4, 100°C) . The
rubber had substantially no odor.
[0178]
The rubber had 16.6% by weight of a boiling n-hexane-
insoluble matter and 83.4% by weight of a boiling n-hexane-
soluble matter. The boiling n-hexane-insoluble matter had a
reduced viscosity of 1.4 and showed a peak of 201.2°C in the
endothermic curve by DSC. The boiling n-hexane-soluble
matter had a Mooney viscosity of 32 (ML1+4, 100°C) , a toluene
solution viscosity of 82, a weight-average molecular weight

of 400,000, and consisted of 98.5% of a cis-1,4 structure,
0.7% of a trans-1,4 structure and 0.8% of a 1,2-structure.
[0179]
(Example 4)
A polybutadiene was synthesized in the same manner as
in Example 3 except that a 3 wt. % bleaching powder
[(CaCl(OC1)]-suspended water was added at the time of
stopping the polymerization. The rubber obtained had
substantially no odor.
[0180]
(Example 5)
A polybutadiene was synthesized in the same manner as
in Example 3 except that a 3 wt. % high test hypochlorite
(calcium hypochlorite)-suspended water was added at the time
of stopping the polymerization. The rubber obtained had
substantially no odor.
[0181]
(Example 6)
A polybutadiene was synthesized in the same manner as
in Example 3 except that an aqueous 3 wt. % potassium
chlorate solution was added at the time of stopping the
polymerization. The rubber obtained had substantially no
odor.
[0182]
(Comparative Example 2)
A polybutadiene was synthesized in the same manner as
in Example 3 except that no aqueous sodium hypochlorite
solution was added at the time of stopping the polymerization.
The rubber obtained had an offensive odor.
[0183]

(Example 7)
(Aging of catalyst)
There were mixed 5.2 ml of cyclohexane, 1.5 mmols of
diisobutyl aluminum hydride (0.75 ml of a cyclohexane
solution), 0.31 mmol of butadiene and 0.05 mmol of NDV3
(neodymium Versatate) (a cyclohexane solution). The mixture
was subjected to aging at 50°C for 5 minutes. 0.15 mmol of
diethyl aluminum chloride (a cyclohexane solution) was added,
followed by aging for 25 minutes.
(Cis 1,4-polymerization)
Into a 2-liter (content volume) autoclave whose content
had been purged with nitrogen gas, was fed a butadiene
solution consisting of 25 wt. % of 1,3-butadiene and 75 wt. %
of cyclohexane. Thereto were added 2.5 mmols of diisobutyl
aluminum hydride (1.25 ml of a cyclohexane solution) and the
total amount of the aged catalyst solution obtained above.
Polymerization was conducted at 60°C for 30 minutes.
(Syndiotactic-1,2 polymerization)
To the above-obtained cis polymerization mixture were
added 15 mg of carbon disulfide, 3.5 mmols of triethyl
aluminum and 35 mg of cobalt octylate. The mixture was
stirred at 60°C for 15 minutes, to subject the remaining
1,3-butadiene to syndiotactic-1,2 polymerization.
2 ml of an aqueous sodium hypochlorite (0.2 mol/L)
solution was added, followed by stirring for 5 minutes to
stop the polymerization reaction. Then, the polymerization
mixture was treated according to an ordinary method to
recover a polybutadiene rubber.
The polybutadiene rubber obtained gave a yield of 97 g
and showed a Mooney viscosity of 51 (ML1 + 4, 100°C) . The

rubber had substantially no odor.
[0184]
The rubber had 14% by weight of a boiling n-hexane-
insoluble matter and 8 6% by weight of a boiling n-hexane-
soluble matter. The boiling n-hexane-insoluble matter had a
reduced viscosity of 1.6 and showed a peak of 202.4°C in the
endothermic curve by DSC. The boiling n-hexane-soluble
matter had a Mooney viscosity of 23 (ML1+4, 100°C) , a toluene
solution viscosity of 91, a weight-average molecular weight
of 600,000, and consisted of 98.2% of a cis-1,4 structure,
0.9% of a trans-1,4 structure and 0.9% of a 1,2-structure.
[0185]
(Comparative Example 3)
A polybutadiene was synthesized in the same manner as
in Example 7 except that no aqueous sodium hypochlorite
solution was added at the time of stopping the polymerization.
The rubber obtained had an offensive odor.
[0186]
(Example 8)
(Cis 1, 4-polymerization)
The content of a 5.0-L (content volume) autoclave was
purged with nitrogen. Thereinto were injected 3 L of a
solution (FB) consisting of cyclohexane (900 ml), cis2-butene
(1,200 ml) and 1,3-butadiene (900 ml), followed by stirring
for 30 minutes. Then, the mixture was measured for water
content using a Karl Fischer water tester to obtain an
average water content of 10 ppm. The same operation was
repeated and 3 liters of the FB was placed in an autoclave.
Thereinto was injected 340 ml (a volume at 20°C at 1 atm.) of
hydrogen gas using an integrating mass flow meter. Then, 45

mg of carbon disulfide and 56 mg of water (H20) were added,
followed by stirring for 30 minutes for dissolution. Then, 6
ml of triethyl aluminum (a toluene solution of 1 mmol/L) was
added. 3 minutes later, 3 mL of cyclopentadienyl vanadium
trichloride (CpVCl3) (a toluene solution of 0.005 mmol/mL)
was added, and 12 mL of triphenyl carbenium
tetrakis(pentafluorophenyl) borate [Ph3CB(C6F5) 4] (a toluene
solution of 0.0025 mmol/mL) was added. Matrix polymerization
was conducted at 40°C for 30 minutes.
(Syndiotactic-1,2 polymerization)
Then, 1.7 ml of cobalt octoate (a toluene solution of
0.1 mmol/ml) was added, followed by polymerization for 30
minutes. After the completion of the polymerization, 2 ml of
an aqueous sodium hypochlorite (0.2 mol/L) solution was added
to stop the polymerization reaction. Then, stirring was
continued for 5 minutes. The polymerization mixture was
treated according to an ordinary method to recover a
polybutadiene rubber.
The polybutadiene rubber obtained gave a yield of 190 g
and showed a Mooney viscosity of 38 (ML1 + 4, 100°C) . The
rubber had substantially no odor.
[0187]
The rubber had 6% by weight of a boiling n-hexane-
insoluble matter and 94% by weight of a boiling n-hexane-
soluble matter. The boiling n-hexane-insoluble matter had a
reduced viscosity of 1.5 and showed a peak of 204°C in the
endothermic curve by DSC. The boiling n-hexane-soluble
matter had a Mooney viscosity of 27 (ML1+4, 100°C) and a
toluene solution viscosity of 84, and consisted of 88.9% of a
cis-1,4 structure, 0.8% of a trans-1,4 structure and 10.5% of

a 1,2-structure.
[0188]
(Example 9)
A polybutadiene was synthesized in the same manner as
in Example 8 except that a 3 wt. % bleaching powder
[(CaCl(OC1)]-suspended water was added at the time of
stopping the polymerization. The rubber obtained had
substantially no odor.
[0189]
(Example 10)
A polybutadiene was synthesized in the same manner as
in Example 8 except that a 3 wt. % high test hypochlorite
(calcium hypochlorite)-suspended water was added at the time
of stopping the polymerization. The rubber obtained had
substantially no odor.
[0190]
(Example 11)
A polybutadiene was synthesized in the same manner as
in Example 8 except that an aqueous 3 wt. % potassium
chlorate solution was added at the time of stopping the
polymerization. The rubber obtained had substantially no
odor.
[0191]
(Comparative Example 4)
A polybutadiene was synthesized in the same manner as
in Example 8 except that no aqueous sodium hypochlorite
solution was added at the time of stopping the polymerization.
The rubber obtained had an offensive odor.
[0192]
(Example 12)

(Cis 1,4-polymerization)
The content of a 2-L (content volume) autoclave was
purged with nitrogen. Thereinto was fed a solution
consisting of 390 ml of toluene and 210 ml of butadiene. The
temperature of the solution was adjusted to 30°C. Then, 0.90
ml of a toluene solution of diethyl aluminum hydride (DEAH)
(2 mol/L) was added, followed by stirring at 550 rpm for 3
minutes. Then, 1.8 ml of a toluene solution of tris(2,2,6,6-
tetramethylheptane-3,5-dionato) yttrium (20 mmols/L) was
added. The mixture was heated to 40°C. Stirring was
conducted for 4 minutes. Then, 0.18 ml of a toluene solution
of triphenyl carbenium tetrakispentafluorophenyl borate (0.43
mol/L) was added, and polymerization was initiated.
Polymerization was conducted at 40°C for 30 minutes.
(Syndiotactic-1,2 polymerization)
Then, 1.8 ml of a toluene solution of triethyl aluminum
(TEA) (1 mol/L) was added. Successively, water was added so
that its content became 0.5 mmol/L. There were added 1.8 ml
of a toluene solution of cobalt octylate [Co(Oct)2] (0.05
mol/L) and 0.36 ml of a toluene solution of carbon disulfide
(1 mol/L), followed by polymerization at 40°C for 10 minutes.
2 ml of an aqueous sodium hypochlorite (0.2 mol/L)
solution was added, followed by stirring for 5 minutes to
stop the polymerization reaction. The polymerization mixture
was treated according to an ordinary method to recover a
polybutadiene rubber.
The polybutadiene rubber obtained gave a yield of 100 g
and showed a Mooney viscosity of 82 (ML1+4, 100°C) . The
rubber had substantially no odor.
[0193]

The rubber had 11.2% by weight of a boiling n-hexane-
insoluble matter and 88.8% by weight of a boiling n-hexane-
soluble matter. The boiling n-hexane-insoluble matter had a
peak of 2 03.9°C in the endothermic curve by DSC.
[0194]
(Example 13)
A polybutadiene was synthesized in the same manner as
in Example 12 except that a 3 wt. % bleaching powder
[(CaCl(0C1)]-suspended water was added at the time of
stopping the polymerization. The rubber obtained had
substantially no odor.
[0195]
(Example 14)
A polybutadiene was synthesized in the same manner as
in Example 12 except that a 3 wt. % high test hypochlorite
(calcium hypochlorite)-suspended water was added at the time
of stopping the polymerization. The rubber obtained had
substantially no odor.
[0196]
(Example 15)
A polybutadiene was synthesized in the same manner as
in Example 12 except that an aqueous 3 wt. % potassium
chlorate solution was added at the time of stopping the
polymerization. The rubber obtained had substantially no
odor.
[0197]
(Comparative Example 5)
A polybutadiene was synthesized in the same manner as
in Example 12 except that no aqueous sodium hypochlorite
solution was added at the time of stopping the polymerization.

The rubber obtained had an offensive odor.
[0198]

[0199]
The measurement results of volatile components, shown
in Table 1 agreed well with the results of odor test by
olfactory sense.
[0200]
In the following Examples and Comparative Example, each
polybutadiene rubber obtained by adding Irganox 152 0 which is
known as an anti-oxidant after the stop of polymerization was
measured for oxidative deterioration property, and the
results are shown. Time to oxidative deterioration time was
measured and used as an indication of oxidative deterioration
property.
[0201]
Measurement of oxidative deterioration
A polymer placed in a DSC tester was kept at a

predetermined temperature in an air atmosphere and measured
for a time in which the heat generation appeared owing to the
oxidative deterioration of the polymer. A longer time up to
the appearance of heat generation indicates that the
oxidative deterioration is less likely to occur.
[0202]
(Comparative Example 6)
Polymerization was conducted in the same manner as in
Comparative Example 1 except that 1,000 ppm of Irganox 1520
(anti-oxidant) was added to a polymer after the stoppage of
polymerization. The polybutadiene rubber obtained was
measured for oxidative deterioration property at 140°C, 145°C
and 150°C. The results of the measurement are shown in Table
2.
[0203]
(Example 16)
Polymerization was conducted in the same manner as in
Example 1 except that 1,000 ppm of Irganox 1520 (anti-
oxidant) was added to a polymer after the stoppage of
polymerization caused by addition of an aqueous sodium
hypochlorite solution. The polybutadiene rubber obtained was
measured for oxidative deterioration property at 140°C, 145°C
and 150°C. The results of the measurement are shown in Table
2.
[0204]
(Example 17)
Polymerization was conducted in the same manner as in
Example 16 except that 1,350 ppm of Irganox 1520 was added to
a polymer. The polybutadiene rubber obtained was measured
for oxidative deterioration property at 140°C, 145°C and 150°C.

The results of the measurement are shown in Table 2.
[0205]
(Example 18)
Polymerization was conducted in the same manner as in
Example 16 except that 1,700 ppm of Irganox 1520 was added to
a polymer. The polybutadiene rubber obtained was measured
for oxidative deterioration property at 140°C, 145°C and 150°C.
The results of the measurement are shown in Table 2.
[0206]
(Example 19)
Polymerization was conducted in the same manner as in
Example 16 except that 2,000 ppm of Irganox 1520 was added to
a polymer. The polybutadiene rubber obtained was measured
for oxidative deterioration property at 140°C, 145°C and 150°C.
The results of the measurement are shown in Table 2.
[0207]
Table 2

[0208]
The above results revealed the followings. When the
addition amount of the anti-oxidant is insufficient as is in
Example 16, the oxidation deterioration was about equal to or
slightly inferior to that of Comparative Example 6 in which
the anti-oxidant was added in the same amount but no aqueous

sodium hypochlorite solution was added; however, when a
sufficient amount of the anti-oxidant was added as is in
Examples 17 to 19, as compared with the case of no addition
of sodium hypochlorite, the effect of decomposition
prevention was obvious.
Industrial Applicability
[0209]
The VCR obtained by the present invention is extremely
low in odor and, therefore, can be used, per se or by being
compounded with other rubber and, as necessary, various
additives, in various applications, for example, rubber
applications wherein mechanical properties and abrasion
resistance are required, such as tire and various other
industrial products (e.g. hose and belt). The VCR can also
be used as a modifier for plastic. Accordingly, the present
invention provides an industrially useful technique.

Claims
[1] A method for producing a polybutadiene, which comprises
firstly subjecting 1,3-butadiene to cis-1,4
polymerization ,and subsequently subjecting a resultant in
resulting polymerization system to syndiotactic-1,2
polymerization, the method being characterized in that there
is added, after the polymerization, a halogen acid or a
halogen acid salt, both represented by the following general
formula (I):
M'(X'Oq)rZ's (I)
(wherein M' is a metal atom or a hydrogen atom; X' is a
halogen atom selected from chlorine, bromine and iodine; 0 is
an oxygen atom; q is an integer of 1 to 4; Z' is an anion
capable of bonding to M'; r is an integer of 1 or more; and
r+s is the oxidation number of M').
[2] A method for producing a polybutadiene according to
Claim 1, wherein X' is chlorine.
[3] A method for producing a polybutadiene according to
Claim 1, wherein the compound represented by the general
formula (I) is hypochlorous acid or a hypochlorous acid salt.
[4] A method for producing a polybutadiene according to any
of Claims 1 to 3, wherein the catalyst used in the
syndiotactic-1,2 polymerization is a catalyst comprising a
cobalt compound, an alkyl aluminum compound and a sulfur
compound.
[5] A method for producing a polybutadiene according to any
of Claims 1 to 4, wherein the catalyst used in the cis-1,4
polymerization is a catalyst comprising a cobalt compound, an
organic aluminum compound and water.
[6] A method for producing a polybutadiene according to

Claim 5, wherein the organic aluminum compound is a trialkyl
aluminum compound represented by R13Al (wherein R1 is a
hydrocarbon group having 1 to 10 carbon atoms) and a halogen-
containing aluminum compound represented by R23_nAlXn (wherein
R2 is a hydrocarbon group having 1 to 10 carbon atoms, X is
halogen, and n is a number of 1 to 2) .
[7] A method for producing a polybutadiene according to any
of Claims 1 to 4, wherein the catalyst used in the cis-1,4
polymerization is a catalyst obtained by subjecting, to aging,
components selected from a compound of group 3 metal of
periodic table, an alkyl aluminum hydride compound, butadiene,
methyl aluminoxane and a chlorine-containing compound.
[8] A method for producing a polybutadiene according to any
of Claims 1 to 4, wherein the catalyst used in the cis-1,4
polymerization is a catalyst obtained from a metallocene type
complex of a transition metal compound, an ionic compound
between non-coordinating anion and cation, an organic metal
compound of a group 1 to 3 element of periodic table and
water [(organic metal compound of group 1 to 3 element of
periodic table)/(water) = 0.66 to 5 (molar ratio)].
[9] A method for producing a polybutadiene according to any
of Claims 1 to 4, wherein the catalyst used in the cis-1,4
polymerization is a catalyst obtained from (A) an yttrium
compound, (B) an ionic compound between non-coordinating
anion and cation, and (C) an organic metal compound of an
element selected from group 2, group 12 and group 13 of
periodic table.
[10] A method for producing a polybutadiene according to
Claim 9, wherein there is used, as the yttrium compound (A),
an yttrium compound having a bulky ligand, represented by the

following general formula:
[formula 1]

(wherein R1, R2 and R3 are each hydrogen or a hydrocarbon
group having 1 to 12 carbon atoms, 0 is an oxygen atom, and Y
is an yttrium atom).
[11] A method for producing a polybutadiene according to any
of Claims 1 to 10, wherein the polybutadiene is a reinforced
polybutadiene comprising (1) 3 to 30% by weight of a boiling
n-hexane-insoluble matter and (2) 97 to 70% by weight of a
boiling n-hexane-soluble matter.

Disclosed is a method for producing a polybutadicne wherein 1,3-butadiene is subjected to a cis-1,4 polymerization
by using a catalyst and then the resulting is subjected to a syndiotactic-1,2 polymerization in the same polymerization system. This
method for producing a polybutadiene is characterized in that a halogen acid or a halogen acid salt is added after the polymerization.