Note: Descriptions are shown in the official language in which they were submitted.
2089~2
HOECHST AKTIENGESELLSCHAFT ~OE 92/F 045 Dr. SR/rh
Description
Cycloolefin block copolymers and a process for their
preparation
~he invention relates prLmarily to a proce~s for the
preparation of cycloolefin blo-k copolymer~, the polymer
chain~ being mad~ up of at least two chemically di~ferent
blocks and the cycloolefin being polymerized without ring
opening. The transition from one block to the next ~an be
via an intermediate block, the chaxacteristic feature of
which is that in said intermediate block there i~ a
continuous, gradual change in the chemical structure from
that of the one block towards the chemical struct~re of
the next block~
The cycloolefin copolymers which can be prepared by known
processes (cf. for example EP-A 407 870) have a random or
presumably alternating chain structure. However, these
copolymers, which, in principle, are suitable for the
preparation of a multiplicity of moldings, as a rule have
only low toughness which is expressed, for example, in
elongations at break of 5 8 % and in this re~pect are
therefore worth improving.
Cycloolefin copolymers which have hiyh heat distortion
resistance al~o have relatively high melt vi~co~ity.
Block copolymers based on 1-olefins are de~cribed in the
application WO 91/12285.
One method for improving the toughness o~ a poly~r i~ to
mix the corresponding polymer with a so-calle~ flexible
phase, a polymer which h~ a diEtinctly lower glass
transition temperature. Because of the co~tent of
flexible component, mixtures of this type in principle
also have lower melt viscosity~
:
i , .
- 2 _ 2 0 8 9 ~ ~2
It is very frequently found that mixtures of aycloolefin
copolymers having very different gla88 transition tempe-
ratures are not compatible with one another Incompati-
bility is as a rule associated with poor mechanical
properties if care i~ not taken that good phase binding
results.
A common method for improving pha~e binding i~ the
admixture o a polymer phase promoter, the characteri~tic
feature of which is that its chain is physically or
chemically anchored both in the first and in the ~econd
phase (cf. Rub~er Toughened Plastics, Adva~c0s in
Chemistry Series, Washington DC, 222, 1989; ppO 3 - 64).
The object on which the invention i5 based was thus to
find a phase promoter for cycloolefin copol~mer~ of
different glass transition temperatures and a process for
its preparation.
It has been found, surprisingly, that when the polymeriz-
ation is conducted in a particular way, based on cata-
lysis using metallocene catalysts, polymers are formed
~0 which are very suitable as phase promoters and in variol1s
cases even facilitate miscibility of different cyclo-
olefin copolymers. In this context miscibility signifies
that thP finished polymer mixture has a single glass
transition temperature or that the gla~ transition
temperatures of the mixture are closer together than the
glass transition temperatures of the pure components.
Kinetic studies have shown that the polymer material~
prepared according to the invention are cycloolefin block
copolymers.
The invention thus relates to a process for the prepara-
tion of a cycloolefin block copolymer, wherein 0.1 to
95 % by weight, with respect to the total ~mount of
monomers employed, of at least one monomer of the
2~8~2
-- 3 --
formulae I, II, III, IV, V o:r VI
/CH\ Rl
¦¦R'-C--R~
\¦ / ~R2
H C f C H
¦IR3 - C - R~ ¦ CH2 ( I I ) .
HC\I ,CH
/ ¦ \ ~ I \ /
llr3--C--R4 ¦R~--C R ¦ (
\ I H ~ \ C H /
H C/ ¦ \C H~ ¦ \C H~l \C H/
I ~S-C--R4 ¦R5--C R ¦ R7- C-R3 ¦ ( I Y) .
R s
/ I \ / \ /
~!R -C--R4 1 ¦ (V) .
HC\I ~CH /CH
CH CH \R~
~S
f
C H \C ~ ~C H \ R 2
;
2~99~2
- 4
in which Rl, R2, R3, R4, R5, R6, R7 and R~ are identical or
different and are a hydrogen atom or a Cl-C3-alkyl
radical, it being po~sible for the same radicalG in the
various formulae to have different meanings,
0 to 95 ~ by weight, with xespect to the total amount of
monomers employed, of a cycloolefin of the for~ula VII
CH CH
( V l l )
( C H 2 ) n
in which n is a number from ~ to 10, and
0 to 99 % by weight, with respect to the total amount of
monomers employed, of at least one acyclic olein of the
formula VIII
R \ / (Ylll),
,C C~
R~l/ `R'2
in which R9, Rl, Rl1 and R12 are identical or different and
are a hydrogen atom or a Cl-C~-alkyl radical, are poly-
merized at temperatures of -78 to 150C and a pre~ure of
OoO1 to 64 bar, ;n the presence of a catalyst which i~
composed of ~ cocatalyst and a metallocene o the ~ormula
XI R
/ / R~
R18 Ml (X I )
\ R15
R 1 7
:
. .. ~ : .
:
2~8~2
- 5 -
in which
M' is titanium, zirconium, hafnium, va~adium, niobium
or tantaluml
Rl4 and Rls ar~ identical or different and are a hydrogen
atom, a halogen atom, a C,-C,O-alkyl group, a Cl-C10-
alkoxy group, a C6-C,O-aryl group, a C6-ClD-aryloxy
group, a C2oClO~alkenyl group, a C7-C~O-arylalkyl
group, a C7-C~O-alkylaryl group or a Ca-C~D-arylalkenyl
group,0 Rl5 and Rl7 are a mononuclear or polynuclear hydrocarbon
radical which can form a sandwich structure with the
central atom Ml,
Rl2 is
R'9 Rl9 R'9 R'5 Rl9 R~9 Rl9 R
2_ , --U 2_ C R 2 2 ~_ --C _ _ o _ U 2 _ --C--C
R~C ~ R2D R20 R2c R20 R~ R~
= BRl9, = AIRl9, -Ge-, -Sn-, -0-~ -S-, = SO, =SO2,
= NRl9, = CO, = PRl9, or = P(O)Rl9, where R19, R20 and
R2l are identical or different and are a hydrogen
atom, a halogen atom, a Cl-ClO-alkyl group, a Cl-C10-
fluoroalkyl group, a C6-C10-fluoxsaryl group, a C6-
C1O-aryl group, a Cl-C1O-alkoxy group, a C2-C1O-alkenyl
group, a C~-C40-arylalkyl group, a Ca-C40-aralkenyl
group or a C7-C~O-alkylaryl group, or R'9 and R20, or
Rl9 and R2', form a ring, in each ca~e wlth the atom
linking them, and
M2 is silicon, germanium or ti~, ~nd, in ~ach Gase at
~5 a molecular weight diætribution M~/M~ of le~s than 2,
always with respect to the polymer block ~orming,
the reaction condition~ are changed in such a way
that the monomer/comonomer ratio ~hanges by at lea t
10 % or a further polymeri~able monomer of the
formulae I-VIII is metered into the monomer or the
monomers.
.,
,
:
- 6 ~ 2
The polymPrization is carried out in such a way that,
depending on the number of change~ in the parameters or
the monomer composition which are carried out, a two-
stage or multi-stage polymerization takes place, it also
being possible to polymerize a homopolymer 3equence of
one of the monomers of the formulae I to VIII in the
first polymeriæation stage.
Alkyl is straight chain or br~nched alkyl.
For the purposes of the invention, the monocyclic olefin
VII can also be substitu~ed (for ~xample by alkyl or aryl
radicals).
The cycloolefin block copolymers prepared according to
the invention are novel and are also a subject of the
present invention.
Pure monomers of the formulae I to VIII, preferably
monomers of the formulae I to VII and in particular o~
the formulae I or III, or monomer mixtures are used in
the first polymerization stage. In all subsequent poly-
merization stages only monomer mixtures are used.
The monomer mixtures used in the polymerization are
mixtures of one or more eycloolefins, in particular of
the formulae I or III, with one or more acyclic olefins
VIII or mixtures of cycloole~ins exclusively. The monomer
mixture advantageou~ly compri~es 2 monomer~, which ~re
preferably a polycyclic olefin of the formula I or III
and an acyclic olefin of the formula VIIIo
The formulae I or III in particular represent norbornene
or tetracyclododecene respectively, it ~eing po~ible for
these to be substituted by (Cl-C6)-alkylv Formula VIII
pre erably represents l-olefins, in particular ethylene
or propylene.
.
2~9952
,
-- 7 --
Cycloolefin block copolymer~ according to the invention
which may be mentioned are, in particular, norbor-
nene/ethylene block copolymers and tetr~cyclodode-
cene/ethylene block copolymer~, in which each polymer
~equence or each polymer block is made up of a copolymer
and norbornene (in the case of norbornene/ethylene block
copolymers~ or tetracyclododecene (in the case of tetxa-
cyclododecene/ethylene block copolymers) ha~ al~o been
incorporated at least in one polymerization ~tage. The
particularly preferred norbornene/ethylene block copoly-
mers are made up of norbornene/ethylene copolymer ~equen-
ces of different composition, i.e. they are compo~ed of
blocks (polymer segments) which are ~ach norbornene/ethy-
lene copolymers.
The cataly6t to be used for the process according to the
invention comprises a cocatalyst and at least one metal-
locene (transition metal component) of the formula XI
Rls
/ Rl~
Rla ~,~1/ (X I )
\ Rls
Rl7
In formula XI M' iæ a metal selected from the group
comprising titanium, zirconium, hafnium, vanadium,
niobium and tantalum, preferably zirconium and hafnium.
The use of zirconi~n is particularly preferredO
Rl4 and Rls are identical or different and are a hydrogen
atom, a C,-Cl0-alkyl group, preferably a Cl-C3-alkyl group,
a Cl-Cl0-alkoxy group, pr~ferably a Cl-C3-alkoxy group, a
C6-C,0-aryl group, preferably a C6-C8-aryl group, a Cc-C,O-
aryloxy group, preferably a C6-C8-aryloxy group, a C2-CIo-
alkenyl group, preferably a C2-C4-alkenyl group, ~ C,-C~0-
arylalkyl group, preferably a C~-C,0-arylalkyl group, a C7-
9 5 ~
-- 8 --
C40-alkylaryl group, preferably a C7-C12-alkylaryl group,
a C8-C40-arylalkenyl group, prefera~ly a Ca-C,2 arylalkenyl
group, or a halogen atom, preferably chlorine.
Rl6 and R17 are identical or different and are a mono-
S nuclear or polynuclear hydrocarbon radical which can forma r,andwich structure with the central atom Ml. Rl6 and R17
are preferably indenyl, fluorenyl or cyclopentadienyl.
These radicals can be monosubstitu~ed or polysubstituted,
in particular by ( C~-C4 ) -alkyl.
Rl8 is a single-membered or multi-membered bridge which
links the radicals R~6 and R'7 ~nd iB preferably
R'9 Rl9 R 9 R 9 Rl9 Rl9 R~9 Rl9
~ 2_ 1~ 2_ --U 2--C R 2 2 1-- , --C-- --O--~1 2-- --C--C-- ,
2 0 1 2 D I 2 D I 2 0 R ~ D R R
= BR19, = AIRl9, -Ge-, -Sn-~ O-, -S-, = SO, = SO2, = NR'9,
, PR or = P(O)R , where R19, R20 and R21 ar~ id ti
cal or different and are a hydrogen atom, a haloqen atom,
a C1-C10-alkyl qroup, a C1-C10-fluoroalkyl group, a C6-C,0-
aryl group, a C1-C10 alkoxy group, a C2-C10-alkenyl group,
a C7-C40-arylalkyl yroup, a C~-C40-arylalkenyl group or a
C7-C40-alkylaryl group, or Rl9 and R20, or R'9 and R2~, form
a ring, in each case together with the atoms linking
them.
M2 is silicon, germanium or tin, preferably ~ilicon or
germanium.
The prsparation of the metallocenes to be u~ed ac~ording
to the invention is known (cf. Journal of Organometallic
Chem. 288 (1985) 63-67, EP-A 320 762, EP-A 336 128,
EP-A 336 127, EP-A 387 690 and BP A 387 691)~
2~9~2
g
Metallocenes preferably used are:
rac-dimethylsilyl-bis(1-indenyl)zirconium dichloride,
rac-dimethylgermyl-bi~(1-indenyl)zirconium dichloride,
rac-phenylmethylsilyl-bis(l-indenyl)zirconium dichloride,
rac-phenylvinylsilyl-bis(1-indenyl)zirconi.um dichloride,
1-6ilacyclobutyl-bis(1-indenyl)zirconium di~hloride,
rac-diphenylsilyl-bis(l-indenyl)hafnium dichloride,
rac-phenylmethylsilyl-bi~(l-indenyl)hafnium dichloride,
rac-diphenylsilyl-bis(l-indenyl)zirconium dichloride,
rac-ethylene-l,2-bis(l-indenyl)zirconium dichloride,
dimethylsilyl-(9-fluorenyl)-(cyclopentadienyl)zirconium
dichloride,
diphenylsilyl-(9-fluorenyl)-(cyclopentadienyl)zirconium
dichloride,
diphenylmethylene-(9-fluorenyl)-cyclopentadienylzirconium
dichloride,
isopropylene-(9-fluoxenyl)-cyclopentadienyl-zixconium
dichloride,
phenylmethylmethylene-(9-fluorenyl)-cyclopentadienyl-
zirconium dichloride,isopropylene~(9-fluorenyl)-(1-(3-isopropyl)cyclopentadi-
enyl)zirconium dichloride,
isopropylene-(9-fluorenyl~(1-(3-methyl)cyclopentadienyl)-
zirconium dichloride,
diphenylmethylene-~9-fluorenyl)(1-t3 methyl)cyclopentadi-
enyl)zirconium dichloride,
methylphenylmethylene-(9-fluorenyl)(1-(3~methyl)cyclo-
pentadienyl)zirconium dichloride,
dimethylsilyl-(9-fluorenyl)(1-(3-methyl)-cy~lopentadi-
enyl)zirconium dichloride,diphenylsilyl-(9-fluorenyl~ (3-methyl)cyclopentadi-Pnyl)zirconium dichloride/
diphenylmethylene-(9-fluorenyl)tl-l3-tert.-butyl)~yclo-
pentadienyl)zirconium dichloride,
isopropylene-(9-fluorenyl)(1~(3-tert.-butyl)cyclopen adi~
enyl)zirconium dichloride and analogou6 hafnocenes.
2 ~ 2
-- 10 --
Particularly preferred metallocenes areo
rac-dimethylsilyl bis(1-indenyl)zirconium dichloride,
rac-phenylmethylsilyl-bis(1-indenyl)zirconium dichloride,
rac-phenylvinylsilyl-bistl-indenyl)zirconium dichloride,
rac-diphenylsilyl-bis(1-indenyl)zirconium dichloride,
rac-ethylene-1,2-bis(l-indenyl)zirconium dichloride,
dimethylsilyl-t9-fluorenyl)-(cyclopentadienyl)zirconium
dichloride,
diphenylsilyl-(9-fluorenyl)-(cyclopentadienyl)~irconium
dichloride,
diphenylmethylene-(9-fluorenyl~-cyclopentadienyl-
zirconium dichloride,
isopropylene-(9-fluorenyl)-cyclopentadienyl-zirconium
dichloride or
phenylmethylmethylene-(9-fluorenyl)-cyclopentadienyl-
zirconium dichloride and analogous hafnocenes.
The cocatalyst used according to the invention iB prefer-
ably an aluminoxane of the formula (IX)
- Rl3
Rl3--A i--O---A I 0---A l Rl3 ( I X)
for the linear type and/or of the formula (X~
R 1 3
O--A 1~
p ~ 2
for the cyclic type, where, in the formulae IXXj and (X),
the radicals R13 can be identical or different and are a
C,-C6-alkyl group, a ~6-Cl8-aryl group, benzyl or hydrogen,
and p is an integer from 2 to 50, preferably 10 to 35.
The radicals R'3 are pref~rably identical and are methyl,
isobutyl, phenyl or benzyl, particularly preferably
methyl.
If the radicalR Rl3 are different, they are prefer~bly
methyl and hydrogen or alternatively methyl and isobutyl,
the hydrogen or isobutyl content preferably bein~ 0~01 -
40 % (number of radicals R~3).
The aluminoxane can be prepaxed in various way~ by known
processes. One of the methods i8, for example, to react
an aluminum hydrocarbon compound and/or a hydridoaluminum
hydrocarbon compound with water (ga~eous, soli~, liquid
or bound - for example as water of crystallization) in an
inert solvent (such as, fQr example, toluene). In order
to prepare an aluminoxane containing different alkyl
groups R'3, two different aluminum trialkyls (AIR3 ~ AIR'3)
are reacted with water in accordance with the desired
composition (cf. S. Pasynkiewicz, Polyhedron 9 (1990) 429
and EP-A 302 424).
The precise structure of the aluminoxane is not known~
Irre~pective of the mode of preparation, a varying
content of unreacted aluminum starting compound, which is
in a free form or in the form of an adduct, i~ common to
all aluminoxane solutions.
25 It is possible to preactivate the metallocene with an
aluminoxane of the formula (IX~ and/or (X) before it i6
used in the polymerization reactionO The polymeriæation
activity is distinctly increased by this mean~.
The preactivation of the transition metal compound is
carried out in solution. Preferably, the metallocene is
dîssolved in a solution of the aluminoxane in an i~ert
- 12 ~ 2
hydrocarbon. A suitable inert hydrocarbon i~ an aliphatic
or aromatic hydrocarbon. Toluene is preferably u~ed.
The concentration of the aluminoxane in the solution i5
in the range from about 1 ~ by weight up to the ~atura-
tion limit, preferably from 5 to 30 % by weight, in eachcase with respect to the total solution. The metallocene
can be used in ~he C~me concentration, but it i8 prefer
ably used in an amount of 10-4 - 1 mol p~r ~ol of alumi-
noxane. The preactivation time is 5 minut~ to 60 h~ur~,
pr~ferably 5 to 60 minute~. ~he preactivation is carried
out at a temperature of -78C to 100C, pr~ferably 0 to
70C.
The metallocene itself can also be prepolymerized or
applied to a support or enclosed in a prepolymer (for
example on the basis of a metallccene-catalyzed prepoly-
merization). The (or one of the) olefin(s) used in the
polymerization is preferably u ed for the
prepolymerization.
Suitable supports are, for example, silica gels, aluminum
oxides, solid aluminoxane or other inorganic aupport
materials. A polyolefin powder in finely divided form is
also a suita~le support material.
According to the invention, compounds of the formulae
R,~NH" XBR'4, R,~P~4 XBR',~, R3CBR'4 or BR' 3 can be used a~
suitable cocatalyst~, instead of sr in addition to an
aluminoxane. In these formulae x is a number fr~m 1 to 4,
pref~rably 3, the radicals R are identical or different,
preferably identical, and are C1-C,D alkyl or Cc-C~B-aryl,
or 2 radicale R form a ring together with the atom
linking them, and the radic~ls R' are identical or
different, preferably ide~tical, and are C6-C18-~yl,
which can be ~ubstituted by alkyl, haloalkyl or fluorine.
In particular R i8 ethyl, propyl, butyl or phenyl ~nd R'
is phenyl, pentafluorophenyl, 3,5-bi~trifluor~methyl-
-- 2 ~
- 13
phenyl, mesityl, xylyl or tolyl (cf. EP-A 277 003,
EP-A 277 004 and EP-A 426 638~.
When the abovementioned cocatalysts are u6ed, the actual
(active) polymerization cataly~t compri~e~ the reaction
product of metallocene and one of the said ~ompounds.
This reaction product is therefore preferably fir~t
prepared out~ide the polymerization reactor in a ~eparate
step using a suitable solvent.
In principle, any compound which, on the basi~ of its
Lewis acidity, i8 able to convert the neutral metallocene
into a cation and to sta~ilize the latter ("labile
coordination") iB a suitable cocatalyst according to the
invention. In addition, the cocatalyst or the anion
formed therefrom should not enter into any further
reactions with the metallocene cation formed (cf.
EP-A 427 697).
Purification with an aluminum alkyl, for example AlMe3 or
AlEt3, is advantageous in order to remove catalyst poi~on~
present in the olefin. This purification can either be
carried out in the polymerization system itself, or the
olefin i8 brought into contact with the Al compound
before it iB added to the polymerization system and then
separated off again.
If a small amount of solvent i5 added to the reaction
mixture, the solvents u~ed are conventional inert ~ol~
vents, such as, for example, aliphatic or cycloallphatic
hydrocarbon6 (for example cyclohexane, dekalin~, yasoline
fractions or hydrogenated diesel oil fraction~ or
toluene.
The polymerization takes place in dilute ~olution (<30 %
by volume cycloolefin), in concentrated sollltion (>80 %
by volume cycloolefin) or directly in the liquid un~
diluted cycloolefin monomer.
- 14 - 208~52
Depending on the activity of the catalyst and on the
desired molecular weight and the desired molecular weight
distribution of the par~icular polymer block, the temper
ature and reaction time must be matched accordin~ly. The
monomer concentration ~nd the nature of the solvent must
also be taken into account, especially as the~e para-
meters e~sentially determine the relative rates of
incorporation of the monomers ~nd thus are deci~ive for
the ylass transition temperature and heat dietortion
resistance of the polymers.
The lower the polymerization temperature is cho~en within
the range from -78 to 150C, preferably between -78 and
80C and particularly preferably between 20 and 80C, the
longer can be the polymerization time for virtually the
same range of molecular weight distribution MW/M~ for the
particular polymer blocks.
If the sudden change in the reaction conditions takes
place at a time at which the molecular weight distribu-
tion M~/Mn of the polymer block forming is 1, it can
reliably be assumed that all of the polymer blocks formed
in this polymerization stage possess a cataly~t-active
chain end (i.e. the chains are so-called live polymer
chains) and thus a further block can be polymerized onto
these chain ends by changing the polymerization condi-
tions. For thi~ extrema case coupling i~ 100 %, The morethe molecular weight distribution M~/M~ of the polymer
blocks ~ormed in a polymerization ~tage deviatq~ from 1,
i.e. M~/Mn >1, the greater is the increase in ~he number
of catalyst-inactive chain ends (i.e. ~o-called dead
chain ends or ~topped chains), which are no longer
capable of coupling a further block.
For the process according to the invention for the
preparation of block copolymers this siqnifie~ that the
more MW/Mn of the polymer block X prepared in the poly
merization stage X is in the vicinity of the value 1 at
2089~2
- 15 -
the ~ime at which the change in the reaction parameters
takes place the greater will be the proportion of block
polymer chains in the finished product at which a chemi-
cal coupling between block X and block X+1 ha~ been
effected.
With respect to the structural homogeneity or ~urity of
the cycloolefin block copolymers this signifies that the
time window6 for the individual polymerization ~tages
should as far as possible be 80 cho~en that they cor-
respond to an M~/M~ of the corresponding polymer blockæ ofvirtually 1, in order to obtain cycloolefin block copoly~
mers of high purity and high structural homogeneityO
If it is also desired to trigger a ~pecific molecular
weight of a polymer block, the reaction time must also be
adjusted to the desired molecular weight~
The determination of the requisite reaction time beore
the reaction conditions are changed, which varie~ depend-
ing on the said reaction parameters and the rate of
cycloolefin incorporation, is carried out by means of a
calibration by simple sampling as de cri~ed in the
illustrative embodiments. Diagrams from which the re-
quisite times can then be taken (pr ~ rmined) can be
plotted from test series. Fig. 3 ~ hich generally shows
the dependence of the molecular weight distribution M~
of a polymer block on the reaction time t, i8 an example
of such a diagr~m.
With the ex~eption of the first polymerization ~tage in
a discuntinuous proce~, the cali~ration to determin~ the
reaction time for all polymerization ~tages in discon
tinuous and continuous proces3es must be carried out in
separate single-stage experiments in which ~ except for
the reaction time - the particular rsaction conditions of
the corresponding polymerization -~tage are u~ed.
. . .
2 ~ r~ 2
- 16 -
In the case of a copolymerization ~tag~, th~ molar
monomer ratio in the reaction medium of cycloolefins to
acyclicolefins or of a cycloolefin to the other
cycloolefins, if no acyclic olefins are used, i6 then
changed accordingly at the time at which the reaction
conditions are changed. The change in the monomer ratio
should amount to at least 10 %, preferably more than
25 %.
If the first polymerization stage is a homopolymerization
(for example polymerization of norbornene), at lea~t a
second monomer enters the reaction chamber at the time at
which the change is m~de.
During a polymerization stage, or the formatLon of a
polymer block, the monomer ratios in the reaction chamber
are as a rule kept constant, ~o that chemically uniform
polymer blocks are formed. However, it is al90 po~sible
continually to change the monomer ratios during a poly-
merization stage, which then lead~ to polymer blocks
which have a structural gradient along the polymer chain,
i.e. the incorporation ratio (for example the ratio
between the number of norbornene units and the number of
ethylene units in a pdrt of the polymer block) changes
continually along the corresponding polymer bloak. In the
case of polymer blocks which are made up of more than two
types of monomer, this gradient can be aahieved by
continually changing the concentration of a ~ingle
monomer component. Blocks which have structural gradients
can alco be prodllced in those polymerization ~tage~ in
which the concentration of several monomer comp~nents is
changed continuously at the same time. The re~ulting
block copolymers are likewise Gf intere~t and a subject
of the present invention.
The changes in the mor.omer ratios o be carried out in
the proces~ according to the invention can be achieved,
for example, by changing the pressure of the acy~lic
~8~2
- 17 -
olefin, by changing the temperature and thus the 801u-
bility of gaseous olefins, by dilution with ~olvents
under constant pressure of the acyclic olefin or by
metering in a liquid monomer. Several of the ~aid para-
meters can also be changed at the same time.
Both sudden and continuous changes of this type in the
monomer ratio - and thus the preparation of blo~k copoly-
mers according to the invention - ~an be effected both
when the reaction is carried out di~continuou~ly and when
the reaction is carried out ~ontinuously.
Continuous and multistage polymerization pro~esses are
particularly advantageous because they make pos~ible
economically advantageous use of the cycloolefin. In
addition, in continuous processes the cyclic olefin,~
which can be obtained as residual monomer together with
the polymer, can be recovered and recycled to the reac-
tion mixture.
When the polymerization is carried out in this way, the
block length can be controlled via the throughput and
reaction volume of th~ various reaction vessel~ (i.e-.
these two parameters determine the dwell time in the
various reaction locations).
An example of a process of this type i8 ~hown diagram-
matically by Figures l and 2. Figure 1 ~how~ ~ possible
2; set-up for a simple continuous procedure, whioh can be
expanded by further element~ (reaction vessels etcO) if
required. ~he symbols have the following me nings:
Parameters: pressures pl and p2i pl>>p2; throughput v;
throttling d; level adju~tment l;0 Parts: ~tirred vessels R; pump P, tubular reactor
K; valves V
a = gaseous olefin or olefin mixture;
b = cycloolefin or cycloolefin solution; cycloolefin
mixture or ~olution of cycloolefin mixture
':
--`` 2~`~9~52
c - polymer solution;
k - catalyst;
Pr = product.
Figure 2 shows an example of the variation profile for
the reaction conditions to which the re~cting chain end
of a block copolymer chain according to the invention can
be subjected, assuming two pa~ses through the ~ontinuous
reaction cycle which is 6hown diagrammatically in Figure
l, start and discharge of the chain taking pla~e in
reactor chamber Rl.
The symbols have the following meaning~:
X1 = cycloolefin/1-olefin ratio in reaction chamber
Rl
X2 = cycloolefin/1-olefin ratio in reaction chamber
R2
tl+~tl = dwell time in reaction chambex Rl
t2+~t2 = dwell time in reaction chamber R2
+~ = indicates that a dwell time distribution exi6ts
and therefore these times vary about a ~tatis-
tical average value
tl';t2' = dwell time in the tu~es between R1 and R2 or R2
and R1 (in comparison with R1 and R2, the dwell
time distributions in these tube lines are
narrow and therefore the indication "~t" ha~
been dispensed with here; usually the rate of
incorporation of the 1-olsfin i8 yreater than
that of the cycloolefin, which then lead~ to a
slight change in the monomer ratio in favor of
the cycloolefin)
fl;f2 ~ r~latively sudden change in the monomer ratio
on entering the reaction cha~ber R2 or Rl
An installation according to ~igure 1 can be operated
either continuously, i.e. by permanent pump transfer oi
the reaction ~olution or permanent metering o~ the
monomers and discharge of the product ~olution, or
' ''~'~ ` . ..
~ .
- lg- ~9g~2
discontinuously by batchwise pump tran~fer of the entire
reaction solution from reactor to reactor.
The discontinuous variant has the advantage that both
block length and the number of blocks per polymer chain
can be precieely adjusted. In the ca~e of the continuous
procedure, the block l~ngth can be accurately controlled,
whilst the number of blocks is acce~sible or adjustable
as a statistical average over the achieved average
molecular weight of the block copolymer and the aLmed-at
averaqe molecular weight of the polymer blocks. The
prPparation of block copolymers which have ~pecific block
chain ends can be effected very accurately using the
discontinuous procedure, whereas the continu~us process
enables only statistical information in this respect.
It follows that the described change in the reaction
conditions (parameters) can be carried out one or more
times, which leads to a sequence of two or more different
blocks within a pslymer chain. The only condition with
which it is necessary to comply is that the particular
start of -the reaction ror the formation of a new block is
so chosen that the latter takes place at a time at which
- according to the calibration - the molecular weight
distribution MW/M~ o~ the growing polymer block is stiil
~2, preferably virtually 1. If this condition is complied
with, a new block which has a new composition can always
be polymerized onto ihe growing polymer chain. These
reaction times vary depending o~ the catalyst system
used, the reaction temperature and the monomer concentra-
tion.
If no further new block is to be polymerized on, the
polymerization is completed, i~e~ discharged or ~toppad,
under the last chosen reaction conditions.
A discontinuous procedure can also be carried out in one
reaction ve~sel in that the change in the r0action
conditions and stopping of the reaction are carried out
2 0 ~ 2
- 20 -
successively in one reactor.
In general the following applie~ with respect to the
reaction parameters:
If pure open-chain olefin, for example ethylene, is being
injected under pressure, pxes~ure~ of between 0.01 and
64 bar, preferably 2 to 40 bar and particularly prefer`ab-
ly 4 to 20 bar are used. I, in addition to the open-
chain olefin, an inert gas, for example nitrogen or
argon, is al~o injected undPr pressure, ~he total pres-
sure in the reaction vessel is 4 to 64 bar, preferably 2to 40 bar and particularly preferably 4 to 25 bar. If the
cycloolefinic component is in the undiluted iorm, a high
rate of incorporation of cycloolefin is also achieved at
high pressures.
The metallocene compound is used in a concentration, with
respect to the transition metal, of 10~1 to 10-8, prefer-
ably 10-3 to 10-6 mol of transition metal per dm3 of
reactor volume. The aluminoxane is used in a concentra-
tion of 10-5 to 10-1, preferably 10-4 to 2 x 10-2 mol per dm3
of reactor volume, with re~pect to the aluminum content~
In principle, higher concentrations are, howe~er, also
possible. The other cocatalysts mentioned are preferably
used in approximately equimolar amounts with respect to
the metallocene.
Apart from the said, bridged metallocene~, metalloc0nes
which have identical or similar non-bridged ligand~ can,
in principle, also be used. In the case of the~e me~al-
locenes, the reaction times chosen must be distinctly
shorter tha~ those for the bridged metallocene~, under
comparable xeaction conditions.
When preparing copolymers, the molar ratios of the
polycyclic ol~fin to the open-chain olefin (preferably)
used can be varied within a wide range. The molar ratios
of cycloolefin to open-chain olefin are preferably
2~Y,~9!~,
- 21 -
adjusted to 50:1 to 1:50, in particular 20:1 to 1:20.
The cycloolefin block copolymers according to the inven-
tion lead to advantageous mechanical property co~ina-
tion~ in blends with other cycloolefin copolymer~.
S The following examples are intended to illu~trate the
invention in more detail:
Example 1
A clean and dry 1.5 dm3 polymeri~Ation reactor provided
with a stirrer was flushed with nitrogen and then with
ethylene and filled with 576 ml of an 85 ~ strength by
volume solution of norbornene in toluene.
The reactor was then kapt at a temperature of 20C, with
stirring, and 2 bar ethylene texcess pre~4ure) wa~ in-
jected under pressure.
20 cm3 of a solution of methyl aluminoxane in toluene (MA0
solution) ~10.1 ~ by weight of methyl aluminoxane having
a molar mass of 1300 g/mol according to cryoscopic
determination) were then metered into the reactor and the
mixture was stirred Ior 15 min at 20C, the ethylene
pressure being kept at 2 bar by metering in additional
ethylene. In parallel, 60 mg of rac-dimethylsilyl-bis(l-
indenyl)zirconium dichloride were di~solved in 10 cm3 of
a solution of methyl aluminoxane in toluene (~ee above
for concentration and quality) and preactivated by
leaving to ~tand for 15 minutes. The ~olution of th~
complex was then metered into the reactor. Polymerization
was then carried out at 20C, with stirrin~ 1750 rpm),
the ethylene pressure bein~ kept at 2 bar by metering in
additional ethylene.
After 30 min, 50 ml of the reaction solution were removed
via a lock. Immediately after this sampling, the ethylene
2~9~2
- 22 -
pressure was increased to 7 bar in the course of 10 sec
and kept at this pressure for 5 min by metering in
additional ethylene~ The polymerization was then ~topped
ky adding lO ml of water via a lock. ~fter ~ubsequent
letti~g-down, the reaction solution was drained into a`
vessel and then added dropwise to 2 d m3 of acetone, the
resulting mixture w ~ 9 stirred for 10 min and the ~u~pend
ed, polymer solid was filtered off.
20 g of polymer which has a gla6s transîtion temperature
of 140C and a vi~cosity number of g5 ml/g and a mole-
cular weight distribution M,,,/ Mn Of 1.5 were obtained.
After removal, the 50 ml of sample were treat~d, with
stirring, with 0.5 ml of water and then worked up analo-
gously to the abovementioned working-up of the reaction
solution of the end product. 4.5 g of polymer which has
a glass transition temperature of 165C, a visco~ity
number of 150 mlig and a molecular weight distribution
MW/Mn of 1.3 were isol~ted from the 50 ml of sample.
-
Examples 2 - 4
The procedure was analogous to Example 1 but, in deviat-
ion therefrom, the condition6 from Table 1 w~re cho~e~.
The resulting polymer properties are summarized in ~ble
2.
Table 1:
_ _ .
Example Nb ~olution PolymorisationPolymerlsation h~ount o~
No. ConC~ntratiDn St~ge 1 Stag ~ 2 ~otallDccno
(~ by volum~ Timn Et prn3auro Ti~ ~t pre~ure ~g)
~rlin) j ~bar) ~min) ~oar)
2 24.4 30 1 15 7 ~0.3
3 24.4 30 1 10 7 92.2
4 43.B 30 2 2 6 69.9
_ _
Nb ~ NorbDrn~no
- 23 -
~able 2:
Example5ample ~n~ product
No. Vn Tg ¦ Mwt~Vn Tg M~
(ml/g) (C) - (ml/g) (~C)
2 22 167 1.2 10898 1.2
3 27.5 165 1.2 19281 1.6
4 73 173 1.2 107134 1.3
. . _ __
Example 5
A kinetic te6t was carried out analogously to Example 1.
860 cm3 of an 85 % strength by volume solution of norbor-
nene in toluene were used for the polymerization. The
reactor temperature was 24C and the ethylene sxcess
pressure was kept constant at 6 bar. 60 cm3 of a solution
of MAO in toluene (10.1 ~ strength by weight) were added
and the mixture wa~ stirred for 15 min. 21 mg of rac-
dimethylsilyl-bis(1-indenyl)zirconium dichloride were
added to 20 cm3 of MAO solution and after preactivation
the mixture was injected into the reactor under pre~sure.
Samples (50 cm3 ) were taXen via a iock at the reaction
times indicated in Table 3. The polymerization wa~
immediately stopped by adding 4 çm3 of isopropanol. The
product was w~shed several times wikh acetone and dilute
hydrochloric acid (see Example 1).
The resulting polymer product~ were mea~ured by gel
permeation chromatography. The number-average molecular
weight (M~) and weight-average molecular weight ~M~) and
the inhomogeneity (MW/M~) ar~ given in Table 3. The
distribution curves for all samples are shown in Fig. 4.
.
: ~ ,
~- 20~3~5~
- 24
Table 3:
Sample Reaction M~ Mw M~/Mn
No. time/min x 10~3g/molx 10 3g/mol
1 10 21.~ 2~.4 1.10
2 20 37.3 4~.8 1O15
3 30 51.0 62.0 1.22
4 45 73.0 92.0 1.25
83.0 121.0 1.46
6 90 110.0 167O0 1.52
7 120 125.0 217.0 1.74
8 150 153.0 261.~ 1.7l
Fig. 4 shows the molecular weight distribution functions
obtained by gel permeation chromatography for ~mples
Nos. 1 - 8 from Exampla 5 from left to right with in-
creasing molecular wei~ht and increasing reactivn time.
Reaction time and average molecular weights (M~, Mw~ are
given in Table 3.
The area of the dis~ribution function in Fig. 4 is
weighted by the yield.
GPC (gel permeation chromatography) measurements were
carried out as follows. A type 150-C ALC/GPC Millipore
Waters Chrom. chromato~3raph And a column set comprising
4 Shodex columns of type AT-80 M/S were u~edO The solvent
was o-dichlorobenzene.
Further mea~urement parameters were:
Temperature: 135C
30 Flow rate: 0,5 ml/min
5ample amount: 0.4 ml of sample solution
Concentration of
the sample solution 0.1 g/dl
.
2V~9~2
- 25 -
Calibration: according to polyethylene
standard
Example 6
The procedure wa~ analogous to Example 1 but, in devia~
tion therefrom, the following conditionc were ~ho~en:
- cycloolefin = tetracyclodode~ene
- concentration of the cycloolefin solution = 127 g/l
- amount of cycloolefin solution = 860 ml
- amount of NA0 solution = 100 ml
- metallocene = rac-dimethylsilyl-bistl-indenyl~zirconium-
dichloride
- amount of metallocene = 62 mg
- ethylene pressure maintained by additional metering =
3 bar
- sampling time = after 20 min
- the cycloolefin concentration was changed by adding pure
cycloolefin via a lock.
- duration of thP addition operation = 2 ~ec
- amount of cycloolefin metered in = 170 g
- ethylene pressure after addition = 3 bar
- duration of polymerization after m~tering in -- 30 min
The resulting polymers are distinguished by:
- amount of resulting end product = 1705 g
- amount of polymer from sample ~ 390 mg
25 - gla8s transition temperature of the end product ~ 175C
glass transition temperature o~ the polym~r from
sample = 110C
- molecular weight Mn of the end product - 7~,000 g/mol
- molecular weight Mn o the polymer ~r~m s~mple -
52,000 g/mol
- viscosity nu~ber of the end product ~ 105 ml/g
- viscosity number of the polymer from ~ample ~ fi6 ml~g
- molecular weight distribution Mw~Mn of the end
product = 1.9
" 2~9952
- 26 -
- molecular weight distribution ~w/~n of the polymer ~rom
sample = 1.4
Comparison example 1 (compari~on example with respect to
Example 6
The procedure was as in xamPle_6 but, in deviatio~
therefrom, the addition of the pure cycloolefin wa3
already carried out before the addition of the metallo-
cene and thu~ before the start of the polymerization~ The
polymerization was stopped after 3 hour~. The re6ulting
end product i~ distinguished by the following
characteristics:
- glass transition temperature = 151C
- viscosity number = 84 ml~g
Example 7
Polymerization experiments were carrie/ ~out in an instal-
lation corresponding to that in Fig.~10 The installation
was characterized by the following features:
- R1 has a volume of 80 l
- R2 comprises a tube in which static mixing elements are
~ixed
-- R2 has a volume of 2~0 ml
- K is a cooling tube which has a volume of 15 l
- P is a gear pump
The polymerization was carried out in a~cordan~e with the
following concept:
- a olution of cycloolefin in toluene was initially
introduced into R1;
- pllmp transfer was carried out using the pump in a~cor-
dance with a calibration with constant flow rate;
- the gaseous olefin was introduced at excess pre~ure
into the circulation flow immediately upstream of the
~0~9~2
.
~ 27 -
static mixer,
- in reactor Rl the pressure was kept constant by con-
trolled letting-off of gas.
The following polymerization conditions were maintained:
- cycloolefin: norbornene
- gaseous olefin: ethylene
- metallocene:diphenylmethylene-(9-fluorenyl)cyclopenta-
dienylzirconium dichloride
- amount of norbornene (liquid) initially introduced =
10 1
- amount of toluene initially introduced - 30 1
- amount of MAO solution (MAO solution according to
Example 1) initially introduced = 1000 ml
- amount of metallocen~ (catalyst preparation according
to Example 1) = 200 mg
- ethylene excess pressure during the polymerizatioll on
the ethylene line = 11 bar
- pressure in R2 immediately downstream of th~ static
mixing elements = 10.5 bar
- pressure in R1 during the polymerization = 2.5 bar
- circulation stream during the polymerization = 1500 l/h
- polymerization temperature: in R1 = 40C
in R2 = 43C
After the start of the polymerization by addition of the
catalyst via a lock, samples were taken regularly at the
location in the installation designated by Pr in Fig. 1.
The polymerization was stopped after 50 minut~ Workin~
up of the samples and of the end product was c~rr ed out
analogously to Example 1.
The following properties were determined for 8ampl~ and
end product:
- 900 ml sample after 10 minutes:
- amount of polymer = 0.5 g
- glass transition temperature = 140C
`:
~ 2~9~
-- 28 --
- viscosity number = 62 ml~g
- 600 ml sample after 20 minutes~
- amount of polymer = 1. 4 g
- glass transition temperature = 137C
5 - viscosity number = lO9 ml/g
- end product after 50 minutes:
- amount of polymer - 15 g in 1 1 of polymerization
solution
- glass transit' on temperature = 134C
10 - viscosity number = 160 ml/g
Example 8
Two polymer blends were prepared by mixing 5 % strength
toluene solutions of the components and then precipita
ting in acetone and drying the precipitated powder. The
15 following compositions were ~elected:
E~lend I: 3 parts of component A + 3 part~ of component
B ~ 1 part of component C
Blend II: 3 part6 of component A + 3 parts oiE component
B
2 0 Component A is a norbornene-ethylene copolymer poly-
merized in one stage and having a gla~ tran~ition
temperature of 102 C and a viscosity number of 52 ml/g.
The catalyst u~ed for its polymerization wa~ diphenyl-
methyl- t 9~f luorenyl ) -cyclopentadienylzirco~ium
25 dichloride.
Component B iB a norbornene-ethylene copolymer poly-
merized in one stage and having a glass tran~ition
temperature of 178C and a vi~rosity number of 48 ml~O
~he catalyst used for its polymerization was diphenyl-
30 methyl- ( 9-fluorenyl)-cyclopentadienylzirconium
dichloride .
- 29 -
Component C is a block copolymer which was prepar~d by a
process according to Example 1 but, in deviation there-
from, the following condition~ were chosen:
- amount of norbornene solution = 860 ml
- amount of MAO solution = 60 ml
- metallocene = diphenylmethylene-(9-fluorenyl)-cyclo-
pentadienylzirconium dichloride
- amount of metallocene = 20 mg
- ethylene pre~sure maintained by additional metering =
6 bar
- sampling time = after 25 min
- time over which the ethylene pressure was changed -
20 sec
- second ethylene pressure maintained by additional
metering of ethylene = 12 bar
- duration of polymerization at the second ethylene
pressure = 2.5 min
The resulting polymers are distinguished by:
- amount of resulting end product = 13.5 g
- amount of polymer from sample = 370 mg
- glass transition temperature of the end product ~ 1269C
- glass transition temperature of the polymer ~rom
sample = 143C
- molecular weight Mn of the end product = 155,000 g/mol
- molecular weight Mn of the polymer from sample =
90,000 g/mol
- viscosity number of the end product = 176 ml/g
- viscosity number of the polymer from sample ~ 114 ml/g
- molecular weight distribution ~w/Mn of the end
product = 1.8
molecular weight distribution Mw/Mn of the pol~mer from
sample - 1.3
Aft~r drying in an oven at 80C for 18 hours, pressed
sheets were produced from both blends at 240GC, 100 bar
compression pressure and a pres~ing time of 15 minutes.
The sheets have a diameter of 60 mm and a thickness of
20~52
1 mm. Samples, which were used to determine the gla~5
transition tempera~ure, were taken from these sh~ets.
The following glass transition temperatures were
measured:
Blend I: first glass transition temperature = 121~C
~econd ylass transition temperature ~ 163C
Blend II: irst glagB transition temperature z 105C
aecond glass transition temperature = 165~C
As the glaQs transition temperatures confirmt b~th blends
are two-phase. The increase in the fixst glas~ transition
temperature in the case of blend I compared with the
first glass txansition temperature in the case of blend
II apparently shows that the corresponding phase has, as
a result of the addition of the block copolymer, clearly
approached the phase which i6 characterized by the second
glass transition temp~rature, i.e. the two pha~es become
more compatible.
Example 9
The procedure was analogous to Example 8, the component~
being polymerized using rac-dimethylsilyl-bi~ inden-
yl)zirconium dichloride. Deviating from Example 8, the
following characteri~tics apply:
- component A: glass transition temperature = 75~C
viscosity num~er = 97 ml/g
5 - component ~: gla s transition temperature ~ 165~C
viscosity number = 58 ml/g
- component C is a block copol~m r prepared according to
- 31 ~ 2
Example 2.
- blend I haæ a single glass transition temperature of
108C.
- blend II: fir~t glass transition temperatur~ c 88~C
5second glass transition temp~rature ~ 142C
Example 10
The procedure was analogous to Example 8, the components
being polymerized using rac-dimethyl~ilyl-bis(l-
indenyl)æirconium dichloride. Deviating from Example 8,
the following characteristics apply:
- Blend I: 5 parts of component A + 12 parts of com-
ponent B + 3 parts of component C
- ~lend II: 5 parts of component A ~ 12 parts of com~
ponent B
5 - componenk A: glass transition temperature - 15C
viscosity number = 145 ml/g
- component B~ glass transition temperature - 179C
viscosity number = 112 ml/g
- component C is a block copolymer prepared according to
Example 2 but, in deviation therefrom, the following
data pply:
- time for the e~ond polymerization stage ~ 3 min
- Et pressure in the second polymerization stage 8 14 bar
- Vn of the end product = 180 ml/g5 - the end product has two glas~ tran~ition temperature~:
first glass transition temperature = 48a~
æecond glass transition temperature = 148C
- Mw/Mn of the end product - 1.9
' .
. .
~: .
- 32 - 2~ 2
- Blend I: fir~t glaPs transition temperature ~ 30gC
~econd glass txan~ition tempera~ure - 156C
- Blend II: first glass tran~ition temperature = 18C
second glass tran3ition temperature - 173C
Whereas the pressed plates from blend I had a translucent
appearance, the pre3sed plate6 from blend II were opaque.
Dumbbell test pieces for mechanical testi~g were produced
from a further portion of the blends prepared.
Determination of the notched impact strength carried out
on the correspondin~ dumbbell test pieces in acaordance
with ISO 180/A gave the following value~ at a test
temperature of 60C:
Blend I: 6.3 kJ/m2
Blend II: 4.2 kJ/m2
