Process for producing styrenic polymer

Details Process for producing styrenic polymer Process for producing styrenic polymer

2000-02-17

2001-02-20

Teskin, Fred (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S127000, C526S151000, C526S160000, C526S161000, C526S164000, C526S165000, C526S346000

Reissue Patent

active

RE037064

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for producing a styrenic polymer. More particularly, it pertains to a process for producing a styrenic polymer having a high degree of syndiotactic configuration efficiently and inexpensively.
2. Description of the Related Arts
In recent years, a process for producing a styrenic polymer having a syndiotactic configuration (hereinafter sometimes referred to as “SPS”) by polymerizing a styrenic monomer by means of a catalyst comprising a transition metal compound as a primary ingredient, especially a titanium compound and methylaluminoxane (refer to Japanese Patent Application Laid-Open No. 187708/1987) has been proposed.
There has also been proposed a process for efficiently producing such a styrenic polymer (SPS) by the use of a catalyst comprising a coordination complex compound composed of an anion in which a plurality of radicals are bonded to a metal and a cation, while dispensing with an aluminoxane which is expensive and is to be used in a large amount (refer to Japanese Patent Application Laid-Open Nos. 415573/1990, 415574/1990, etc.)
In the case of polymerizing a styrenic monomer by the use of the above-mentioned catalyst, there has heretofore been employed an alkylaluminum as a chain transfer agent for the purpose of modifying the molecular weight of the objective polymer. However, this method involves the problems that the catalytic activity deteriorates resulting in an increase in the amounts of residual metals contained in the styrenic polymer thus produced, allowing the decomposed product of an alkylaluminum to remain in the objective polymer. Even in the case of raising the polymerization temperature, the deterioration of the catalytic activity increases the amount of residual metals in the objective polymer. The aforesaid situation calls for the development of a process capable of producing a styrenic polymer of high performance at a low cost, while enabling a decrease in the molecular weight of the resultant polymer and simplifying the process itself without deteriorating the catalytic activity.
As a result of intensive research and investigation made by the present inventors under such circumstances, it has been found that in the case of polymerizing a styrenic monomer by the use of a transition metal compound, a coordination complex compound composed of an anion in which a plurality of radicals are bonded to a metal and a cation, or methylaluminoxane, and an alkylating agent as principal components, the use of a reaction product between a straight-chain alkylaluminum having at least two carbon atoms and water can lower the molecular weight of the resultant polymer without deteriorating the catalytic activity. The present invention has been accomplished on the basis of the above-mentioned finding and information.
SUMMARY OF THE INVENTION
Specifically, the present invention provides a process for producing a styrenic polymer which comprises polymerizing a styrenic monomer by the use of (a) a transition metal compound, (b) a coordination complex compound comprising an anion in which a plurality of radicals are bonded to a metal and a cation, or methylaluminoxane, (c) an alkylating agent and (d) a reaction product between a straight chain alkylaluminum having at least two carbon atoms and water.
DESCRIPTION OF PREFERRED EMBODIMENT
As an (a) transition metal compound usable in the process of the present invention, mention may be made of a variety of compounds, usually the compound represented by the general formula (I) or (II)
MR
1
a
R
2
b
R
3
c
R
4
4-(a+b+c)
  (I)
MR
1
d
R
2
e
R
3
3-(d+e)
  (II)
wherein M is a metal belonging to any of the groups 3 to 6 of the Periodic Table or a lanthanum series metal; R
1
, R
2
, R
3
and R
4
are each an alkyl group, an alkoxyl group, an aryl group, a cyclopentadienyl group, an alkylthio group, a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, a fluorenyl group, a halogen atom or a chelating agent; a, b and c are each an integer of from 0 to 4; d and e are each an integer of from 0 to 3; and any two of R
1
to R
4
may form a complex which is crosslinked with CH
2
, Si(CH
3
)
2
or the like.
As a metal belonging to any of the groups 3 to 6 of the Periodic Table or a lanthanum series metal as indicated by M, there are preferably employed the group 4 metals, especially titanium, zirconium, hafnium and the like.
Various titanium compounds can be used and a preferred example is at least one compound selected from the group consisting of titanium compounds and titanium chelate compounds represented by the general formula (III) or (IV):
TiR
5
e
R
6
f
R
7
g
R
8
4-(a+b+c)
  (III)
TiR
5
h
R
6
i
R
7
3-(d+e)
  (IV)
wherein R
5
, R
6
, R
7
and R
8
are each a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkylaryl group, an arylalkyl group, an acyloxyl group having 1 to 20 carbon atoms, a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, a fluorenyl group, an alkylthio group, an arylthio group, a chelating agent, an amino group, an amide group, a phosphorus-containing group or a halogen atom; a, b and c are each an integer from 0 to 4; a and e are each an integer from 0 to 3; and any two of R
5
to R
8
may form a complex which is crosslinked with CH
2
, Si(CH
3
)
2
or the like.
R
5
, R
6
, R
7
and R
8
in the general formulae (III) and (IV) each represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms (specifically, methyl group, ethyl group, propyl group, butyl group, amyl group, isoamyl group, isobutyl group, octyl group and 2-ethylhexyl group), an alkoxyl group having 1 to 20 carbon atoms (specifically, methoxyl group, ethoxyl group, propoxyl group, butoxyl group, amyloxyl group, hexyloxyl group, and 2-ethylhexyloxyl group), an aryl group having 6 to 20 carbon atoms, an alkylaryl group, an arylalkyl group (specifically, phenyl group, tolyl group, xylyl group and benzyl group), an acyloxyl group having 1 to 20 carbon atoms (specifically, heptadecylcarbonyloxy group), a cyclopentadienyl group, a substituted cyclopentadienyl group (specifically, methylcyclopentadienyl group, 1,2-dimethylcyclopentadienyl group, pentamethylcyclopentadienyl group and 4,5,6,7-tetrahydro-1,2,3-trimethylindenyl group), an indenyl group, a substituted indenyl group (specifically, methylindenyl group, dimethylindenyl group, tetramethylindenyl group and hexamethylindenyl group), a fluorenyl group, (specifically, methylfluorenyl group, dimethylfluorenyl group, tetramethylfluorenyl group and octamethylfluorenyl group), an alkylthio group (specifically, methylthio group, ethylthio group, butylthio group, amylthio group, isoamylthio group, isobutylthio group, octylthio group and 2-ethylhexylthio group), an arylthio group (specifically, phenylthio group, p-methylphenylthio group and p-methoxyphenylthio group), a chelating agent (specifically, 2,21-thiobis (4-methyl-6-tert-butylphenyl) group, or a halogen atom (specifically, chlorine, bromine, iodine and fluorine). These R
5
, R
6
, R
7
, R
8
may be the same as or different from each other.
More desirable titanium compounds include a titanium compound represented by the formula (V)
TiRXYZ  (V)
wherein R represents a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, a fluorenyl group, or the like; X, Y, and Z, independently of one another, are a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxyl group having 1 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxyl group having 6 to 20 carbon atoms, an arylalkyl group having 6 to 20 carbon atoms, an alkyl- or arylamide group having 1 to 40 carbon atoms or a halogen atom. Here, any one of X, Y and Z and R may form a compound which is crosslinked with CH
2
, SiR
2
or the like.
The substi

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