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Description  |
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This invention relates to a process for preparing a copolymer which
comprises copolymerizing (a) at least one monomer selected from olefins,
polyenes, unsaturated esters of carboxylic acid and unsaturated ethers
with (b) an acrylic monomer in the presence of a catalyst in a poor
solvent for the copolymer to be formed. More specifically, the invention
relates to an improved process for copolymerizing the monomers (a) and (b)
under slurry polymerization conditions to give a copolymer containing the
monomeric units (a) and (b) alternately connected to each other with good
regularity which has a narrow molecular weight distribution and is not
liable to gelling during its formation. This process improves the activity
of the catalyst, and markedly increases the yield of the copolymer per
unit weight of the catalyst. Furthermore, the polymerizing and
post-treating operations have been simplified.
Some prior suggestions are known with regard to a process for producing a
copolymer which comprises copolymerizing (a) at least one monomer selected
from the group consisting of monoolefins, non-conjugated polyenes,
conjugated polyenes, halolefins, unsaturated esters of carboxylic acids
and unsaturated ethers with (b) an acrylic monomer of the following
formula
##STR1##
wherein R.sup.1 is a member selected from the group consisting of a
hydrogen atom, a halogen atom, a cyanide group and alkyl groups and Y is a
member selected from the group consisting of --CN, --COR.sup.2,
--COOR.sup.3 and --CONR.sup.4 R.sup.5, in which each of R.sup.2, R.sup.4
and R.sup.5 is a hydrogen atom or an alkyl group and R.sup.3 is an alkyl
group or a monovalent metal, in a solvent in the presence of a catalyst
composed of (A) a component selected from the group consisting of (i)
organoaluminum halides of the following formula
AlR.sub.n.sup.6 X.sub.3-n
wherein R.sup.6 represents an alkyl group, X is a halogen atom, and n is a
number of more than 0 but less than 3, and (ii) complexes formed between
the halides (i) and organic polar compounds, and (B) an organic peroxide.
These suggestions are disclosed, for example, in Japanese Patent
Publication No. 9950/70 published on Aug. 10, 1970, Japanese Laid-Open
Patent Publiction No. 124190/74 published on Nov. 27, 1974, Japanese Laid
Open Patent Publication No. 125491/74 published on Nov. 30, 1974, Japanese
Laid-Open Patent Publication No. 44282/75 published on Apr. 21, 1975, and
Japanese Laid-Open Patent Publication No. 72988/75 published on June 16,
1975. In these Patent Publications, poor solvents for the copolymers are
exemplified together with solvents for use as a copolymerization reaction
medium. However, none of these Patent Publications disclose that the
copolymerization reactions are carried out under slurry polymerization
conditions, but in all of these suggestions, the reaction is carried out
under solution polymerization or so-called precipitation polymerization
conditions. Since the copolymer formed is soluble in the starting monomer
or monomeric mixture, the reaction advances as solution polymerization
even when a poor solvent for the copolymer is used, thus causing a marked
increase in the viscosity of the system as the copolymerization proceeds.
Or the reaction advances under conditions of precipitation polymerization
which result in the precipitation of the resulting copolymer onto the
reactor walls or stirring device, etc. in the agglomerated and adhered
state. For this reason, the desired copolymer must be recovered by
subjecting the reaction mixture after the reaction to complicated
separating procedures, for example, by adding a large amount of a poor
solvent such as lower alcohols to precipitate the polymer, or by first
dissolving the copolymer agglomerated and adhered to the reactor using a
solvent and then adding a large amount of a poor solvent to precipitate
the copolymer.
The prior suggestions neither disclose the performance of the reaction
under slurry polymerization conditions, nor do they disclose or suggest
that copolymerization can be carried out under slurry polymerization
conditions or the copolymerization under slurry conditions brings about
improvement.
We have extensively investigated copolymerization reactions of the
above-mentioned monomers (a) and (b) in the presence of catalyst. As a
result, we have found that the copolymerization can be carried out under
slurry polymerization conditions by adding the monomers (a) and (b) in
such a way that they remain unrected in the reaction system in specified
amounts, and also adding one or both of the catalyst components (A) and
(B). Under these slurry polymerization conditions, the copolymerization
reaction can be carried out in the very stable state. Thus, the resulting
copolymer is afloat as fine particles in the polymerization system, and
even when the copolymerization progresses, it only results in the
increased number of copolymer particles or the increased particle sizes of
the individual particles. The copolymerization reaction can be continued
without changing to a so-called precipitation polymerization in which the
agglomeration and adhesion of the resulting polymer occur. It has been
found that the yield of the final polymer per unit amount of the catalyst
can be greatly increased probably because the resulting copolymer
particles are dispersed uniformly in the polymerization system. We have
further found unexpectedly that at the same time, the alternate
arrangement of monomer units in the resulting copolymer is repeated
regularly to decrease the tendency to the formation of a random copolymer,
and the copolymer has a narrower distribution of molecular weight. The
process of the invention offers further advantages in that the formation
of gelled copolymers can be substantially avoided, and the polymerization
operation and other post-treating operations such as separation can be
greatly simplified and are easier to perform.
It is an object of this invention therefore to provide an improved,
commercially advantageous process for preparing copolymers which comprises
copolymerizing the monomers (a) and (b) in a poor solvent for the
resulting copolymer in the presence of a catalyst composed of the catalyst
components (A) and (B).
The above and other objects and advantages of the present invention will
become more apparent from the following description.
According to the process of this invention the monomers (a) and (b) are
copolymerized in a poor solvent for the resulting copolymer in the
presence of a catalyst composed of the catalyst components (A) and (B),
while
(I) adding the monomers (a) and (b) to the reaction system so that the
total amount of the monomers (a) and (b) remaining unreacted in the
reaction system is sufficient to maintain the system in the slurried state
under the reaction conditions, and
(II) adding either one or both of the catalyst components (A) and (B) to
the reaction system. The monomers (a) and (b) and the catalyst components
(A) and (B) may be added in small portions continuously or intermittently
so as to meet the conditions (I) and (II) above. The manner of addition is
properly selected according, for example, to the types of monomers (a) and
(b), the types of catalyst components (A) and (B), the reaction
temperature, the stirring conditions, and the type of the poor solvent.
The monomers (a) and (b) are added, however, under conditions which
maintain the reaction system in the slurried state. Where the proportion
of the poor solvent is extremely high, the resulting copolymer can be
rendered afloat as fine particles even when the monomers (a) and (b) are
added at the same time. In such a case, however, the amount of the poor
solvent required is too large to be commercially feasible.
According to the present invention, the amount of the poor solvent can be
drastically reduced by continuously adding monomers (a) and (b) in
portions and adding a fresh supply of the monomers in amounts which
substantially correspond to the amounts of the monomers which have been
converted to the copolymer.
Furthermore, by continuously adding one or both of catalyst components (A)
and (B), the amount of the active seed of copolymerization generated in
the reaction system is maintained constant thereby to render the rate of
conversion of the monomers to the copolymer constant and increase the rate
of polymerization throughout the entire period of polymerization.
In order to maintain the copolymerization reaction system in the slurried
state where the copolymer particles obtained are dispesed uniformly, it is
first of all necessary that the resulting particles should not agglomerate
nor adhere, and the concentration of a solvent for the copolymer should be
sufficiently low, and the concentration of the poor solvent, be
sufficiently high, to maintain the copolymer particulate. Secondarily, it
is necessary that a proper degree of stirring should be applied to the
system so as to prevent the sedimentation of the particles.
As regards the first requirement, saturated hydrocarbon compounds can be
used as the poor solvent, and the monomers and alcohol compounds added for
removing the catalyst residues may act as the solvent. The amounts of
monomers (a) and (b) as the solvent must therefore be considered in the
present invention. The allowable range of the total amount of the
unreacted monomers (a) and (b) present in the reaction system is
determined by varying the copolymerization conditions and measuring the
monomer concentrations in the system until the slurry copolymerization
system changes to a precipitation copolymerization system. For practical
purposes, the total amount of the unreacted monomers (a) and (b) can be
easily predetermined experimentally by preparing solutions of the monomers
having known concentrations according to the types of the monomers (a) and
(b) and the reaction conditons employed, suspending test copolymer
particles in the solutions, and observing the dissolving behavior of these
particles. Preferably, the copolymerization reaction is carried out by
adding the monmers (a) and (b) while the reaction system is maintained in
the slurried state under conditions such that the total amount of the
unreacted monomers (a) and (b) in the reaction system is not more than
about 2.5 moles per liter of the poor solvent.
The molar ratio of monomer (a) to monomer (b) is preferably 1 : about
0.2-5, and each of monomers (a) and (b) may consist of at least one
species.
The amount of the poor solvent is preferably about 0.5 to about 100 times,
more preferably about 1 to about 50 times, the total amount of the
monomers (a) and (b).
The reaction temperature is preferably from about -78.degree. C to about
70.degree. C, more preferably from about -20.degree. C to about 70.degree.
C, especially preferably from about 0.degree. C to a point about
10.degree. C higher than the glass transition point (Tg) of the resulting
copolymer. There is no special restriction on the reaction pressure so
long as the reaction system can be maintained in the slurried state, and
it is generally about 1 to 100 kg/cm.sup.2.
In the process of this invention, the amounts of the monomers (a) and (b)
and the rate of addition should preferably be adjusted so that the total
amount of the monomers (a) and (b) remaining unreacted in the reaction
system is not more than about 2.5 moles per liter of the poor solvent
used.
In order to meet the condition (II), the catalyst component (A) in its
entirety is first placed in the reaction zone, and the catalyst compoent
(B) is added in small portions either continuously or intermittently.
Alternatively, the catalyst component (B) in its entirety is placed in the
reaction zone, and then the catalyst component (A) is added in small
portions either continuously or intermittently. Or, the catalyst
components (A) and (B) may be separately added in small portions.
In the process of this invention, the copolymerization is carried out while
adding the monomers (a) and (b) and the catalyst components (A) and/or (B)
so as to meet the requirements (I) and (II). If all of the monomers (a)
and (b) are first charged, and then reacted while gradually adding the
catalyst components (A) and (B), the copolymer formed at the early stage
immediately dissolves in the monomers, and therefore, the reaction cannot
be performed in the slurried state.
Examples of the poor solvent used for the copolymerization include
aliphatic or alicyclic saturated hydrocarbons, such as propane, butane,
pentane, hexane, heptane, octane, cyclopentane, cyclohexane, and methyl
cyclohexane, and mixtures of aliphatic and alicyclic saturated
hydrocarbons such as petroleum ether, ligroin, kerosene and light oil.
These hydrocarbons are liquid at the reaction pressures and have a boiling
point of not more than 220.degree. C at normal atmospheric pressure. In
addition to the monomers (a) and (b), a solvent for the polymer may be
added in amounts which can maintain the resulting polymer in the suspended
state. The poor solvent can be used also as a solvent for the preparation
of a complex (ii) from the organoaluminum halide (i) and the organic polar
compound.
The copolymerization can be carried out in a single reaction tank, or in a
plurality of reaction tanks connected in series. Furthermore, the reaction
can be carried out continuously while adding the monomers (a) and (b) and
the catalyst components (A) and/or (B) on one hand, and withdrawing a
suspension of the resulting copolymerization product continuously from the
reaction zone on the other, under the conditions (I) and (II).
As stated above, in the process of this invention, the reaction system is
maintained under slurry copolymerization conditions by performing the
reaction so that the unreacted monomers (a) and (b) which act as a solvent
for the resulting copolymer are not present in excess in the reaction
system. According to the type of the resulting copolymer, its solubility
in a mixture of the unreacted monomers and the poor solvent can vary. The
amounts of the unreacted monomers in the reaction system can vary
depending not only upon the amounts of the monomers added to the reaction
system and the rate of addition, but upon the rate of copolymerization
(i.e., the rate of consumption of the monomers). Hence, the reaction is
carried out under the slurry copolymerization conditions by properly
choosing a combination of the conditions (I) and (II).
For example, in the case of a combination of an aliphatic monoolefin (a)
and the monomer (b), the reaction should preferably be carried out while
adding the monomers so that the total amount of the unreacted monomers
will become not more than about 2.5 moles, preferably not more than about
1.5 moles, especially not more than about 1 mole, per liter of the poor
solvent. For other combinations, the preferred total amount of the
monomers (a) and (b) remaining unreacted in the reaction system is, for
example, not more than about 2.5 moles, especially not more than about 1.5
moles, in the case of a combination of an aromatic monoolefin (a) and the
monomer (b); not more than about 2.5 moles, further not more than about
1.2 moles, especially not more than about 0.8 mole, in the case of a
combination of a conjugated polyene (a) and the monomer (b); not more than
about 2.5 moles, especially not more than about 2 moles, in the case of an
unsaturated ester of a carboxylic acid (a) and the monomer (b); not more
than about 2.5 moles, further not more than about 2 moles, especially not
more than about 1 mole, in the case of a combination of a haloolefin (a)
and the monomer (b); and not more than about 2.5 moles, further not more
than about 1.2 moles, especially not more than about 0.8 mole, in the case
of a combination of an unsaturated ether (a) and the monomer (b), all
amounts being per liter of the poor solvent.
When the copolymerization in accordance with this invention is carried out
while the total amount of the unreacted monomers (a) and (b) is maintained
extremely low (that is, while the amount of the poor solvent is increased
exceedingly), the agglomeration and adhesion of the resulting copolymer
particles as a result of their contact are certainly reduced, and the
stability of the particles increases. On the other hand, however, this
causes a decrease in the yield of the copolymer per unit amount of the
solvent used, and a slower rate of copolymerization, thus requiring a
longer period of polymerization. In order, therefore, to disperse the
resulting copolymer in the form of particles and to maintain the practical
activity and rate of copolymerization, it is preferred to perform the
copolymerization while the total amount of the unreacted monomers (a) and
(b) is being maintained as close to the upper limit of the allowable range
as possible from the initial to the last stage of the reaction period.
The reaction is preferably carried out with stirring while maintaining the
slurry copolymerization system. It is especialy preferred to employ
stirring conditions which impart a sufficient stirring action to the
reaction system. Stirring is also useful in the process of this invention
to prevent the resulting copolymer particles from sedimenting and
depositing, and thus from changing the reaction system to a precipitation
polymerization system. In actual operation, the stirring action should be
of sufficient degree to maintain the resulting copolymer particles in the
uniformly dispersed and suspended state in the system throughout the
polymerization period. It is difficult to describe this condition more
specifically since it varies according, for example, to the shape of the
polymerization apparatus and the method of stirring employed. Since it is
prefered that the copolymer particles in the system are afloat uniformly,
and the chances of collision among the particles are reduced, the stirring
should preferably result in maintaining the solution part of the
copolymerization system in a state of laminar flow rather than in a state
of turbulent flow. When the most common rotating stirring method is
employed, the requirement for achieving this state is such that the linear
velocity of the solution on the wall surface of the polymerization
apparatus is 10 to 500 m/min., preferably 20 to 40 m/min., more preferably
40 to 300 m/min.
Examples of the monomer (a) used in this invention include for example,
aliphatic monoolefins containing 2 to 18 carbon atoms such as ethylene,
propylene, 1-butene, 2-butene, isobutene, 1-pentene, 1-hexane,
2-methyl-1-pentene, 4-methyl-1-pentene, 1-decene, 1-octadecene, vinyl
cyclobutane, vinyl cyclopentane, and vinyl cyclohexene; alicyclic
monoolefins containing 5 to 8 carbon atoms such as cyclopentene,
cyclohexene and cyclooctene; and aromatic monoolefins containing 8 to 13
carbon atoms such as styrene, .alpha.-methylstyrene, .alpha.-ethylstyrene,
.alpha.-propylstyrene, vinyl toluene, vinyl xylene, isopropenyl toluene,
vinyl naphthalene and isopropenyl naphthalene; non-conjugated polyenes
containing 5 to 10 carbon atoms such as 1,4-pentadiene, 1,5-hexadiene,
1,7-octadiene, 3-chloro-3,7-dimethyl-1,6-octadiene, 4-vinyl-1-cyclohexene,
2,4-dimethyl-4-vinyl-1-cyclohexene, and 1,5-cyclooctadiene; conjugated
polyenes containing 4 to 12 carbon atoms such as butadiene, isoprene,
1,3-pentadiene, 1,3-hexadiene, 1,3,5-hexatriene, chloroprene, and
2-phenyl-1,3-hexadiene; haloolefins containing 2 to 10 carbon atoms such
as vinyl chloride, allyl chloride, 4-chloro-1-butene, 3-chloro-1-butene,
chlorostyrene, 4-chlorovinyl cyclohexane, methallyl chloride, vinylidene
chloride, and the corresponding bromides and iodides; unsaturated esters
of carboxylic acids containing 3 to 10 carbon atoms such as vinyl formate,
vinly acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl
benzoate, allyl acetate, allyl propionate, allyl benzoate, ispropenyl
acetate, methallyl acetate and 1 -butenyl acetate; and unsaturated ethers
containing 3 to 10 carbon atoms such as methyl vinyl ether, ethyl vinyl
ether, propyl vinyl ether, butyl vinyl ether, methyl allyl ether, ethyl
allyl ether, methyl methallyl ether, and ethyl methallyl ether. In the
process of this invention, at least two of these monomers may be used
simultaneously.
The acrylic monomer (b) used as a comonomer in the process of this
invention is expressed by the following formula
##STR2##
wherein R.sup.1 is a member selected from the group consisting of a
hydrogen atom, a halogen atom, a cyanide group, alkyl groups preferably
containing 1 to 6 carbon atoms, and aryl groups preferably containing 6 to
12 carbon atoms; and Y is a member selected from the group consisting of
--CN, --COR.sub.2, --COOR.sub.3 and --CONR.sup.4 R.sup.5, in which each of
R.sup.2, R.sup.4 and R.sup.5 is a hydrogen atom, an alkyl group preferably
containing 1 to 4 carbon atoms, an aryl group preferably containing 6 to
12 carbon atoms, or a cycloalkyl group preferably containing 6 to 12
carbon atoms, and R.sub.3 is an alkyl group preferably containing 1 to 18
carbon atoms, an aryl group preferably containing 6 to 12 carbon atoms, a
cycloalkyl group preferably containing 6 to 12 carbon atoms, or a
monovalent metal such as lithium, sodium or potassium.
Examples of the monomer (b) include acrylic acid esters containing 4 to 22
carbon atoms such as methyl acrylate, ethyl acrylate, propyl acrylate,
butyl acrylate, amyl acrylate, hexyl acrylate, octadecyl acrylate, allyl
acrylate, tolyl acrylate, phenyl acrylate, benzyl acrylate, cyclohexyl
acrylate, and 2-chloroethyl acrylate; esters of .alpha.-substituted
acrylic acids containing 5 to 23 carbon atoms such as methyl methacrylate,
ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl
methacrylate, octadecyl methacrylate, benzyl methacrylate, phenyl
methacrylate, tolyl methacrylate, cyclohexyl methacrylate, 2-chloroethyl
methacrylat, methyl .alpha.-ethylacrylate, ethyl .alpha.-ethylacrylate,
methyl .alpha.-n-propylacrylate, methyl .alpha.-n-butylacrylate, methyl
atropate, and methyl .alpha.-chloromethylacryate; unsaturated nitriles
containing 3 to 5 carbon atoms such as acrylonitrile, methacrylonitrile,
and vinylidene cyanide; alkali metal salts of acrylic acid or
.alpha.-substituted acrylic acids containing 3 to 5 carbon atoms such as
lithium acrylate, sodium acrylate, potassium acrylate, lithium
methacrylate, sodium methacrylate, and potassium methacrylate; unsaturated
ketones containing 4 to 10 carbon atoms, such as methyl vinyl ketone,
ethyl vinyl ketone, phenyl vinyl ketone and methyl isopropenyl ketone; and
unsaturated amides containing 3 to 11 carbon atoms such as acrylamide,
N-methyl acrylamide, N,N-dimethyl acrylamide, N-butyl acrylamide, and
methacrylamide. Of the monomers (b) illustrated above, the acrylate esters
have especially high polymerization activity.
The catalyst used in the process of this invention is composed of (A) a
component selected from the group consisting of (i) organolauminum halides
of the following formula
AlR.sub.n.sup.6 X.sub.3-n
wherein R.sup.6 is an alkyl, alkenyl, aryl, aralkyl or cycloalkyl group,
preferably an alkyl group containing 1 to 12 carbon atoms, an aryl group
containing 6 to 12 carbon atoms, and a cycloalkyl group containing 6 to 12
carbon atoms; X is a halogen atom; and n is a number of more than 0 but
less than 3, and (ii) complexes formed between said halides (i) and
organic polar compounds, and (B) an organic peroxide.
The organic aluminum halide (i) is either a single compound such as
AlR.sup.6 X.sub.2, AlR.sub.2.sup.6 X or AlR.sub.1.5.sup.6 X.sub.1.5 or a
mixture of at least two compounds selected from R.sub.3.sup.6 Al,
AlR.sup.6 X.sub.2, AlR.sub.2.sup.6 X, AlR.sub.1.5.sup.6 X.sub.1.5 and
AlX.sub.3. In these formulae, n represents any number between 0 and 3,
preferably 1 .ltoreq. n .ltoreq. 2. R.sup.6 represents an alkyl, alkenyl,
aryl, aralkyl or cycloalkyl group containing 1 to 12 carbon atoms.
Specific examples of R.sup.6 are alkyl groups such as methyl, ethyl,
propyl, butyl, hexydl, decyl and dodecyl, alkenyl groups such as allyl,
aryl groups such as phenyl and tolyl, aralkyl groups such as benzyl, and
cycloalkyl groups such as cyclohexyl. X represents chlorine, bromine,
iodine and fluorine.
Specific examples of the organoaluminum halide (i) include alkylaluminum
halides containing 1 to 12 carbon atoms such as methylaluminum dichloride,
ethylaluminum dichloride, propylaluminum dichloride, butylaluminum
dichloride, hexylaluminum dichloride, dodecyaluminum dichloride,
methylaluminum dibromide, ethylaluminum dibromide, propylaluminum
dibromide, butylaluminum dibromide, methylaluminum sesquichloride,
ethylaluminum sesquichloride, propylaluminum sesquichloride, butylaluminum
sesquichloride, hexylaluminum sesquichloride, dimethylaluminum chloride,
diethylaluminum chloride, dipropylaluminum chloride, dibutylaluminum
chloride and dihexylaluminum chloride; alkenylaluminum halides containing
3 to 12 carbon atoms such as allylaluminum dichloride, allylaluminum
dibromide and diallylaluminum chloride; arylaluminum halides containing 6
to 12 carbon atoms such as phenylaluminum dichloride and diphenylaluminum
chloride, and the corresponding bromides, iodides and fluorides;
cycloalkylaluminum halides containing 6 to 12 carbon atoms, such as
cyclohexylaluminum dichloride; aralkylaluminum halides containing 8 to 12
carbon atoms such as benzylaluminum dibromide and benzylaluminum
sesquichloride; and mixed organoaluminum halides such as a mixture of
triethyl aluminum and aluminum chloride, a mixture of tripropyl aluminum
and aluminum chloride, a mixture of triethyl aluminum and aluminum
bromide, and a mixture of triethyl aluminum and aluminum iodide.
In the process of this invention, the organoaluminum halide (i) may be used
alone as the catalyst component (A). But preferably, it is used as a
complex (ii) formed between it and a monomer containing a hetero atom
(organic polar compound) whih may be either one of the monomers (a) and
(b) used in the invention. Complexes of the organoaluminum halides (i)
with the acrylic monomers (b) are especially preferred.
In addition to the compounds exemplified hereinabove as the monomer (b),
those usable for complex formation also include, for example, esters of
unsaturated carboxylic acids containing 6 to 12 carbon atoms such as ethyl
atropate, dimethyl maleate, diethyl maleate, dipropyl maleate, dibutyl
maleate, dimethyl fumarate, diethyl fumarate, dipropyl fumaraate, dibutyl
fumarate, dimethyl itaconate, dimethyl citraconate, and dimethyl
tetrahydrophthalate; amides of unsaturated carboxylic acids containing 6
to 12 carbon atoms such as atropamide, maleinamide, N,N-dimethyl
maleinamide, N,N,N',N'-tetramethyl maleinamide, itaconamide,
citraconamide, tetrahydrophthalamide and maleinimide; nitriles of
unsaturated carboxylic acids containing 6 to 12 carbon atoms such as
.alpha.-phenyl acrylonitrile, maleonitrile, fumaronitrile, itaconitrile
and citraconitrile; anhydrides of unsaturated carboxylic acids containing
5 to 12 carbon atoms such as maleic anhydride; itaconic anhydride,
citraconic anhydride and tetrahydrophthalic anhydride; unsaturated esters
of carboxylic acids containing 3 to 10 carbon atoms such as vinyl formate,
vinyl acetate, vinyl propionate, vinyl butyrate, vinyl valerate, vinyl
benzoate, allyl acetate, allyl propionate, allyl butyrate, isopropenyl
acetate, methallyl acetate, and 1-butenyl acetate; and unsaturated ethers
containing 3 to 10 carbon atoms such as methyl vinyl ether, ethyl vinyl
ether, propyl vinyl ether, butyl vinyl ether, methyl allyl ether, ethyl
allyl ether, methyl methallyl ether, and ethyl methallyl ether.
Organic polar compounds selected from the monomers (a) and (b) are used
either alone or in admixture of two or more. Of these organic polar
compounds, the unsaturated carboxylic acid esters; and the unsaturated
esters of carboxylic acids are preferred. The use of acrylate esters and
methacrylate esters is especially preferred. The amount of the organic
polar compound is 1 to 50 moles, preferably 1 to 10 moles, per mole of the
organoaluminum halide (i).
In the formation of the comlex (ii), other organic polar compounds (i.e.,
compounds other than the monomers (a) and (b) may be used. They include,
for example, ethers, esters, aromatic ketones, cyclic acid anhydrides,
amines, amides, nitriles, thioethers, sulfoxides, and sulfones.
Specific examples of other organic polar compounds are ethers containing 2
to 8 carbon atoms such as diethyl ether, ethyl propyl ether, ethyl butyl
ether, ethyl hexyl ether, dipropyl ether, dibutyl ether, anisole, diphenyl
ether, methylene glycol dimethyl ether, methylene glycol diethyl ether,
ethylene glycol diphenyl ether, trimethylene glycol dimethyl ether,
trimethylene glycol diethyl ether, tetramethylene glycol dimethyl ether,
pentamethylene glycol dimethyl ether, hexamethylene glycol dimethyl ether
and veratrole; cyclic ethers containing 4 to 8 carbon atoms as furan,
2-methylfuran, and benzofuran; aromatic ketones containing 8 to 13 carbon
atoms in which at least one aryl group is bonded to the carbonyl group,
such as acetophenone, propiophenone, and benzophenone; carboxylic acid
esters containing 3 to 18 carbon atoms (excepting those containing a
conjugated double bond at the carbonyl group, such as acrylic or
methacrylic esters), for example, (1) ethyl formate, butyl formate, methyl
acetate, ethyl acetate, propyl acetate, butyl acetate, amyl acetate, hexyl
acetate, octyl acetate, decyl acetate, phenyl acetate, benzyl acetate,
methyl propionate, ethyl propionate, propyl propionate, butyl propionate,
and phenyl propionate, and esters of butyric acid, valeric acid, caproic
acid, caprylic acid, benzoic acid, and phenylacetic acid corresponding to
the above-exemplified esters, (2) dimethyl oxalate, diethyl oxalate,
dimethyl succinate, diethyl succinate, dipropyl succinate, dibutyl
succinate, diphenyl succinate, and dibenzyl succinatee, and esters of
glutaric acid, adipic acid and phthalic acid corresponding to the
above-exemplified esters, (3) methylene glycol diacetate, ethylene glycol
diacetate, and ethylene glycol dipropionate, and esters of trimethylene
glycol, tetramethylene glycol, pentamethylene glycol and diethylene glycol
corresponding to the above-exemplified esters, and (4) lactones such as
.beta.-propiolactone, .gamma.-butyrolactone, .gamma.-valerolactone, and
.epsilon.-caprolactone; carbonate esters containing 3 to 15 carbon atoms
such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate,
diphenyl carbonate, dibenzyl carbonate and ethylene carbonate; acid
anhydrides containing 4 to 8 carbon atoms and having a cyclic structure
such as succinic anhydride, glutaric anhydride and phthalic anhydride;
nitriles containing 2 to 8 carbon atoms (excepting those containing a
conjugated double bond such as acrylonitrile and methacrylonitrile) such
as acetonitrile, propionitrile, butyronitrile, valeronitrile,
capronitrile, benzonitrile, malononitrile, and glutaronitrile; tertiary
amines containing 3 to 12 carbon atoms such as triethylamine,
tripropylamine, tributylamine, and N,N,N',N'-tetramethylethylenediamine;
amides containing 3 to 12 carbon atoms such as dimethyl formamide;
thioethers containing 4 to 12 carbon atoms such as diethyl thioether,
dipropyl thioether and dibutyl thioether; sulfoxides containing 4 to 12
carbon atoms such as dimethyl sulfoxide and diphenyl sulfoxide; and
sulfones containing 4 to 12 carbon atoms such as diethyl sulfone and
thiophene-1,1-dioxide.
These other organic polar compounds can be used either alone or in
admixture of two or more. The amount of the other organic polar compound
is 1 to 50 moles, preferably 1 to 10 moles, per mole of the organoaluminum
halide (i) as in the case of those selected from the monomers (a) and (b).
The complex (ii) can be formed by sufficiently mixing the organoaluminum
halide (i) and the organic polar compound at a temperature of about
-50.degree. C to about +80.degree. C in a poor solvent used for
copolymerization. A preferred mixing procedure involves adding the
organoaluminum halide (i) dropwise to a solution of the organic polar
compound in solvent, and stirring the mixture for a while after the
addition. The complex between these two components is the one in which the
lone electron pair of the hetero atom of the organic polar compound is
coordinated with the aluminum atom of the organoaluminum halide (i), as
confirmed by its nuclear magnetic resonance spectrum.
Formation of a complex (ii) between the organoaluminum halide (i) and an
organic polar compound other than the monomers (a) and (b) is effected
preferably such that the amount of the organic polar compound to be
reacted corresponds to 1 to 50, preferably 1 to 10, ether linkages (in the
case of ethers), 1 to 50, preferably 1 to 10, carbonyl groups (in the
case of aromatic ketones), 1 to 50, preferably 1 to 10, ester linkages (in
the case of carboxylic acid esters), 0.5 to 25, preferably 0.5 to 5
carbonate groups (in the case of carbonate esters), 0.5 to 25, preferably
0.5 to 5, acid anhydride structures (in the case of cyclic acid
anhydrides), 1 to 50, preferably 1 to 10, nitrile groups (in the case of
nitriles), 1 to 50, preferably 1 to 10, amino groups (in the case of
tertiary amines), 1 to 50, preferably 1 to 10, amine linkages (in the case
of amides), 1 to 50, preferably 1 to 10, sulfur atoms (in the case of
thioethers and sulfoxides), or 1 to 50, preferably 1 to 10, sulfur atoms
(in the case of sulfones), all being for each aluminum atom of the
organoaluminum halide.
In general radical copolymerizations, the composition of a copolymer is
determined by the type of monomers and their proportions charged. The
present invention has the advantage that when a complex (ii) formed
between the organoaluminum halide (i) and the organic polar compound is
used, the composition of the resulting copolymer can be changed by
selecting the type of the organic polar compound.
The second catalyst component (B) used together with the component (A) is
an organic peroxide. Generally, those having a half life of 1 to 10 hours
in decompositions reactions at 50.degree. to 120.degree. C are generally
preferred, but useful organic peroxides are not limited to them. Usable
organic peroxides include, for example, diacyl peroxides containing 4 to
18 carbon atoms, ketone peroxides containing 4 to 20 carbon atoms,
hydroperoxides containing 4 to 10 carbon atoms, dialkyl peroxides
containing 8 to 18 carbon atoms, and peroxy esters containing 5 to 15
carbon atoms. Specifically, examples of the diacyl peroxides containing 4
to 18 carbon atoms are acetyl peroxide, propionyl peroxide, isobutyryl
peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide,
3,3,5-trimethylhexanoyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl
peroxide, di-isopropyl peroxydicarbonate, di-2-ethylhexyl
peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, and acetyl
cyclohexylsulfonyl peroxide; examples of the peroxy esters containing 5 to
15 carbon atoms are tert-butyl peroxyacetate, tertbutyl peroxyisobutyrate,
tert-butyl peroxypivalate, tertbutyl peroxyreodecanoate, tert-butyl
peroxy-2-ethylhexanoate, tert-butyl peroxy 3,3,5-trimethylhexancate,
tert-butyl peroxylaurate, tert-butyl peroxybenzoate, di-tert-butyl
diperoxyphthalate, and tert-butyl peroxyisopropylcarbonate; examples of
the ketone peroxides containing 4 to 20 carbon atoms are methyl ethyl
ketone peroxide and cyclohexanone peroxide; examples of the hydroperoxides
containing 4 to 10 carbon atoms are tert-butyl hydroperoxide, cumene
hydroperoxide, di-isopropylbenzene hydroperoxide, p-menthane hydroperoxide
and 2,5-dimethylhexane 2,5-dihydroperoxide; and examples of the dialkyl
peroxides containing 8 to 18 carbon atoms are di-tert-butyl peroxide,
tert-butyl cumyl peroxide, di-cumyl peroxide, 2,5-dimethyl-
2,5-di(tertbutylperoxy) hexane, and 2,5-dimethyl-2,5-di(tert-butylperoxy)
hexyne-3.
Of these peroxides, those containing the group
##STR3##
are most preferred.
In the performance of the process of the present invention, the amount of
the catalyst component (A) is preferably about 1/1,000,000 to about 1
mole, more preferably about 1/10,000 to about 1/10 mole, calculated as the
organoaluminum halide (even in the case of the complex (ii)) per mole of
the monomers (a) and (b) combined. The amount of the component (B) is
preferably about 1/100 to about 100, more preferably about 1/10 to about
10, per mole of the organoaluminum halide (i) (in the case of the complex
(ii), the molar amount is calculated as the organoaluminum haide).
The following examples illustrate the present invention more specifically.
EXAMPLE 1 AND COMPARATIVE EXAMPLE 1
A 2-liter six-necked separable polymerization flask equipped with a
vane-type stirring rod connected to a motor controllable as to its
rotating speed, a condenser, a thermometer, a stopper cock and two
metering pumps was disposed in a constant-temperature tank including a
temperature controlling device, and the inside of the flask was thoroughly
purged with nitrogen. 1065 ml of n-hexane and 35 millimoles of eth | | |
