Note: Descriptions are shown in the official language in which they were submitted.
~C)50~L9l
1 .This invention relates to a method for pro-
ducing a novel block copolymer resin which is transparent
and excellent in mechanical properties~ More particularly,
it relates to a novel method for producing a block co-
polymer resin which is transparent 9 excellent in mechanical
properties, particularly in elongation and impact resist-
ance 9 and not susceptible to flexural stress clouding.
It has heretofore been known that block
copolymers.of various structures are obtained by co-
polymerizing vinyl aromatic compounds and conjugateddienes with an alkali metal or an organo-alkali-metal
compound as inltiator. There has.been disclosed, for
example, in Japanese Patent Publication NoO 19,286/61,
a method for block-copolymerizing styrene 9 butadiene,
etc., in two stages using a lithium compound; in
Japanese Patent Publication No. 2,423/73, a method for
synthesizing a three-blocks copolymer in two stages
. using similar monomers; in Japanese Patent Publication
~os. 3,252/72 and 28 9 915/72, methods for preparing a
transparent resin by feeding similar monomers alter-
nately in four or five stages; and in Japanese Patent
Application ~aid-Open ("Kokai") No. 7,597/71, German
Patent Application Iaid-Open (Offenlegungsshri~t)
No. 2,120,232 9 and Japanese Patent Publication No.
20,038/73, methods for preparing a transparent resin
by single stage polymerization from similar monomers.
These methods employ a.s the polymerization
initiator an organolithium compound generally known as
one-end initiation type or that known as both-ends
initiation type In either case 9 these methods are
. - 1 -
-
111)5019~L
1 characterized by forming a polymer by means of a living
anionic polymerization technique so tha-t each polymer
molecule may comprise a plastic block composed chiefly
of polymerized vinyl ar~matic compound and an elastomeric
block composed chiefly of polymerized conjugated dieneO
It has been known9 however, that when the elastomeric
block is composed exclusively of a homopolymer of a
conjugated diene, the block copolymer obtained is not
sufficient for practical use in elongation, impact
strength, and resistance to flexure among mechanical
properties (~xample 11 in Japanese Patent Publication
~oO 19,286/61; Japanese Patent Publication ~o. 2,42~/73),
giving rise to a disadvantage of the block copolymer
in practical application as a resin. On the other
hand 9 in a method where a monomer mixture is added all
at a time [Japancse Patent ~pplication ~aid-Open ("Kokai")
~o. 7,597/71; German Patent Application ~aid-Open
(9'0ffenlegungsschrift") No. 2,120,Z32; Japanese Patent
Publication NoO 20,038/73], there is always formed a
copolymer block between the plastic block composed
chiefly of polymerized vinyl aromatic compound and the
ela~tomeric block composed chiefly of conjugated diene
owing to the difference in monomer reactivites. In
this case, however, a technical difficulty is encountered
2~ in removing a large quantity o* heat evolved from the
polymerization of monomers which have been added all
at a time. Such a difficulty would certainly be
deterrent to the co~mercialization of the method.
The present inventors had conducted exten-
sive investigations to develop a method for producing
-- 2 -
iO:~L9~lL
1 from a vinyl aromatic compound monomer and a conjugated
diene monomer as starting materials a transparent resin
which is excellent in mechanical properties, particular-
ly in impact resistance, and susceptible to nei~her
flexural stress clouding nor reduction in mechanical
properties at low temperatures. As a resultS it was
found that the above object can be achieved by a
method for producing a block copolymer by means of
an anionic living polymerization technique using an
organolithium compound as initiator, which method
comprises forming the block copolymer so as to contain
in the molecule at least one plas.tic block composed
of homopolymerized vinyl aromatic compound and at least
one elastomeric block partly composed of randomly co-
polymeriz.ed vinyl aromatic compound and conjugateddiene in a specified ratio. ~ased on this ~inding,
the present mvention has been accomplished.
. An object of this invention is.to provide
:~ a novel resin9 which is transparent and excellent in
mechanical properties, obtained from a vinyl aromatic
compound monomer and a conjugated diene monomer as
starting materials and a method ~or preparing same.
Other objects and advantages of this inven-
tion will become apparent from the followlng descrip-
25 tion. . - .
This invention provides a method for producing
a transparent block copolymer resin, which is characterized
by the following five essential conditions in block-
. copolymerizing 90 to 65 parts by weight of a vinyl
aromatic compound monomer and lO to 35 parts by weight
: - 3 -
,
. . .
1050~L9~.
1 of a conjugated diene monomer in a hydrocarbon solvent
with an organolithium compound as initiator: (1)
formation of a block copolymer having i~ the moleculc
at least one plastic block composed of homopolymerized
~inyl aromatic compound and at least one elastomeric
block composed of randomly copolymerized vinyl aromatic
compound and conjugated diene, (2) formation of said
plastic block composed of homopolymerized vinyl aromatic
compound by use of 50 to 90 % by weight of the vinyl
aromatic compound monomer, (3) formation of said
elastomeric block in such a manner that it may con-
tain a randomly copolymerized segment formed by con-
tinuously feeding to the polymerizing system a monomer
mi~ture of the vinyl aromatic compound and the conjugated
diene in a fixed ra-tio in the range from 0.1 to 3.0,
a homopolymerized conjugated diene segment, and/or a
randomly copolymerized segment formed by feeding all
:. . .
at a time or continuously to the polymerization system
a monomer mixture of the vinyl aromatic compound and
the conjugated diene in a fixed weight ratio of less
- than 0.1, preferably in the range from 0.001 to 0.1;
the first named randomly copolymerized segment occupy-
ing 50 % by weight or more of the elastomeric block,
(4) formation of the block copolymer having an average
molecular weight of 0.35 to 1.8 dl/g in terms of
intrinsic viscosity, as measured in toluene at 30C.,
and (5) the polymerization conducted in the presence
or absence of 0.01 to 5 mole-% based on total monomer
- of a Iewis base compound. The present method would
present no particular difficulty in commercializ~tion.
lO SO ~L9 1
1 The block copolymer resin thus produced is characterized
by transparency, excellent mechanical properties 9
particuiarly a high impact resistance, little sus-
ceptibility to flexural stress clouding9 and good
processability, permitting the resin to be used in
manufacturing sheeting, filmg usual molded articles,
and in other fields where ordinary resins are used.
The method of this invention is explained
below in detail.
The ~inyl aromatic compounds for use in this
invention are styrene and ~-methylstyrene, vinyl-
naphthalene, and nucleus-substituted styrenes such as
vinyltoluene, and mixtures of these. The conjugated
dienes to be used are 1,3-butadiene and substituted
butadienes such as isoprene, piperylene, 2,3-dimethyl-
l,~-butadiene, l-phenyl-1,3-butadiene, and mixtures of
these. Particularly, styrene among vinyl aromatic
compounds and 1,3-butadiene among con~ugated dienes are
preferable because of their availability and effectiveness.
The monomer composition in this inven-tion
is 90 to 65 parts by weight of a vinyl aromatic com-
pound for 10 to 35 parts by weight of a conjugated
diene. If the ~inyl aromatic compound is used in
excess o~ 90 parts by weLght, the elongation and
impact strength among mechanical properties of the
resin become inferior, while if its amount is reduced
below 65 parts by weight, the tensile strength is
decreased and the processability becomes inferior. In
the present method, the block copolymer obtained has
in the molecule at least one plastic block composcd of
homopolymerized vinyl aromatic compound.
-- 5 --
''"` ' '"'~
. ~
lC~S0~9~; ~
1 In forming said plastic block, are used 50 to 90 %
o~ the total vinyl aromatic compound monomer.
The inert hydrocarbons for use in this
invention as solvent are aromatic hydrocarbons such
as benzene 9 toluene, xylene, and ethylbenzene, aliphatic
hydrocarbons such as hexane and heptane, and cyclo-
aliphatic hydrocarbons such as cyclopentane, cyclo-
hexane, and methylcyclohexaneO These are used each
alone or in mix-tures of two or more~ It is preferable
to use generally 1 to 20 parts by weight of a hydro-
carbon as solvent for one part by weight of the total~
monomer. It is necessary in advance to sufficiently
remove from the above-mentioned solvents and monomers
the substances such as water, oxygen, carbon dioxide,
some kind of sulfur compounds and acetylenes which
destroy the initiators and active ends used in the
present inve~tionO As a variation in the present
method, it is also possible to obtain the block co-
polymer in the form of suspension in a solvent instead
of the form o~ solution, by suitably selecting the
solvent and the order of addition of the monomers.
$he organolithium compound used in the present
method is generally known as an anionic polymerization
initiator of the one~end initiation type or of the
both-ends initiation type. Examples of the individual
compounds include ethyllithium, propyllithium, butyl-
lithium, amyllithium, trimethylenedilithium, tetra-
methylenedilithi~m, hexyllithium, cyclohexyllithium,
phenyllithium, tolyllithium, naphthyllithium, condensed-
ring or non-condensed-ring aromatic lithium complexes,
.
- 6 -
~ 5~
1 and oligobutadienyldilithium or oligoisoprenyldilithium
in living form. These organolithium compounds are
used in an amount of generally 0.002 to 5 mole-%,
preferably 0.005 to 1.5 mole-% based on total monomer.
~he organolithium compounds are used each alone or in
mixtures of two or more.
In the present method; as a part of the
elastomeric block in the molecule, there is formed
at least one random copolymer segment comprising a
vinyl aromatic compound and a conjugated diene and
such a segment occupies at least 50 ~0 by weight of
- the elastomeric blockO In order to allow the poly-
.
merization in this stage to proceed s~oothly, it is
also possible to use specified amounts of a ~ewis base
compound such as, for example, an ether compound or a
tertiary amine compound. Examples o~ effective ether
- compounds are cyclic ethers such as tetrahydro~uran
and tetrahydropyrane; aliphatic monoethers such as
diethyl ether and dibutyl ether; and aliphatic poly-
ethers such as diethylene glycol dimethyl ether and
diethylene glycol diethyl ether. Examples o~ tertiary
amine compounds are triethylamine, tripropylamine,
tributylamine, N,N'-dimethylaniline, pyridine, and
quinoline. When ~uch a ~ewis base compound is used,
the amount to be added is 0.01 to 5 mole-%, preferably
0.05 to 2 mole-% based on total monomer. If it is
used in an amount exceeding the upper limit, content
of vinyl-bond in the copolymer block composed of vinyl
aromatic compound and conju~ated diene and in the
homopolymeriæed conjugated diene block becomes markedly
- 7 -
:~05~
1 high, resulting in marked deterioration in mechanical
properties of the resin, particularly at low tem-
peratures. The ~ewis base compound can be added without
any particular restriction to the polymerization system
at any time prior to the stage where the copolymer
region is formed.
In the present method 7 a vinyl aromatic
compound monomer and a conjugated diene monomer are
block-copolymerized in the presence of an organolithium - ;
compound. The block copolymer thus formed should have
in the molecule at least one plastic block composed
o~ homopolymerized vinyl aromatic compound and at
least one elas-tomeric block containing a segment formed
by copolymerization of a vinyl aromatic compound and
a conjugated diene in a speoified ratio. A block co~
- polymer of a structure in which a homopolymerized vinyl
aromatic compound block is absent or less than 50 %
by weight of the vinyl aromatic compound monomer are
used in forming the homopolymerized block is undesirable
because of defects in mechanical properties, particular-
ly in tensile strength and hardness of the resin. On
the other hand, a block copolymer of a structure in
which more than 90 %9 particularly 100 % by weight, of the
vinyl aromatic compound monomer form the homopolymerized
block is not called a useful resin because it is inferior
in elongation and impact strength among mechanical pro-
perties and easily susceptible to flexural stress
clouding. In a block copolymer of a structure in which
two or more homopolymerized vinyl aromatic compound
blocks are present, sum of the vinyl aromatic compound
1 ~ 5 ~ ~ 9 ~
l used in each homopolymerized block should be 50 to 90 %
by weight o~ the total vinyl aromatic compound monomer.
In the present method, formation of the
elastomeric block from a vinyl aromatic compound and
a conjugated diene should be conducted in such a manner
that the elastomeric block may contain a randomly co-
polymerized segment formed by continuously feeding to
the polymeriæation system a monomer mixture of the
vinyl aromatic compound and the conjugated diene in
lO a fixed ratio in the range from 0.1 to 3.0, a homo-
polymerized conjugated diene segment, and/or a randomly
copolymeri~ed segment formed by feeding all at a time
or continuously to the polymerization system a monomer
mixture of the vinyl aromatic compound and the con-
jugated diene in a fixed weight ratio of less than 0.1,pre~erably in the range from OoOOl to 0.1. The seg-
ments composing the elastomeric block are not necessarily
linked directly to one another but can be distributed
separately throughout the block copolymerO ~he random-
ly copolymerized segment in the elastomeric block shouldbe formed from a continuously fed monomer mixture of
the vinyl aromatic compound and the conjugated diene
in a fixed ratio in the range from 0.1 to 3Ø If
the ratio is decreased below 0.1, the impact resistance
among mechanical properties of the resulting block co-
polymer resin is deteriorated and the susceptibility
to flexural stress clouding is increased 9 while if
the ratio is increased beyond 3.0, the tensile strength
- and hardness of the resin become inferior, both cases
being undesir~ble.
- _ 9 _
.
,.
1~51~19~
1 In the case of a block copolymer having a
molecular structure in which two or more copolymer
segments formed from a monomer mixture of the vinyl
aromatic compound and the conjugated diene in the
specified ratio as mentioned above are present, each
of the segments should be formed from the monomer in
the specified ratio and the ratio between the sum of
the vinyl aromatic compound and the sum of the con-
jugated diene used in forming said segments should be
maintained within the specified range from O.l to 3.0;
the monomer ratio in forming each of the segments can
be the same or different from one another~
The random copolymer segment formed by con-
tinuous feeding of a monomer mixture of the vinyl
aromatic compound and the conjugated diene in a weight
ratio of 0.1 to 3.0 should occupy 50 % by weight or
more of the total elastomeric block. If the proportion
o~ random copolymer segment in the elastomeric block
~ is below 50 ~ by weight, particularly if it is null,
such a block copolymer is undesirable because of its
reduced impact resistance and elongation among mechanical
properties and its enhanced susceptibility to flexural
stress clouding. On the other hand, if the homopoly-
merized conjugated diene segment and/or the copolymer
segment formed from a monomer mixture of the vinyl
aromatic compound and the conjugated diene in a weigh
ratio of less than 0.1, preferably in the range of
OoOOl to 0.1, is absent in the elastomeric block, such
- a block copolymer shows unsatisfactory mechanical pro-
~0 perties, particularly at low temperatures. A preferable
-- 10 -- ,
~050~gl
1 proportion of the random copolymer segment formed froma monomer mixture of the vinyl aroma-tic compound and
the conjugated diene in a weight ratio of 0.1 to 3.0
is in the range from 50 to 90 % by weight of the total
elastomeric block. When two or more segments are
present ln the elastomeric block, the sum of the
segments formed from a monomer mixture of the vinyl
aromatic compound and the conjugated diene in a weight
ratio of 0.1 to 3.0 should be 50 % by weight or more
of the elastomeric block.
- In forming the randomly copolymerized seg-
~ent by continuous addition of a vinyl aromatic compound
and a conjugated diene, both monomers can be fed either
i~ a mixture or separately, maintaining a fixed monomer
ratlo within the aforesaid range. In either case, it
i8 necessary to feed both monomers in a fixed ratio
continuously or substantially continuously to the poly-
merization system under such conditions of polymeriza-
tion temperature and feeding rate that both monomers
will not remain unreacted in the system.
The present method permits to adopt continuous
feeding of the monomers in each stage of forming a block
copolymer. This is one of the characteristic features
of the present method, which allows effective removal
of a large quantity of heat evolved from the polymeri-
zation reaction when carried out on an industrial scale
and, moreover, prevents occurrence of side reactions
such as gelation accompanying the heat evolution.
- - Although the block copolymer formed accord-
ing to the present invention has no restriction placed
~L~SOl91 ~ .
1 on its structure so long as the conditions mentioned
in the foregoing are satisfied~ examples of particularly
. preferred structures are given below, wherein Sl, S2,
and S3 represent homopolymerized vinyl aromatic com-
pound block, (S/B)ls (S/B)29 and ~S/B)~ represent
- randomly copolymerized vinyl aromatic compound and
conjugated diene block, and Bl and~B2 represent homo- -
polymerized conjugated diene block or a block formed
from a monomer mixture of a vinyl aromatic compound and
a conjugated diene in a weight ratio of less than 0.1,
preferably in the range from 0.001 to 0.1.
1) Sl - (S/B)l - Bi
: 2) Sl - Bl - (S/~)l
~) 51 - (S/B)l - Bl - S2
. 4~) Sl - (S/B)l - B1 - (S/B)2 ~ S2
. . 5) Sl - Bl - (S/B)l - B2 ~ S2
6) Sl - (S/B)l - (S/B)2 - Bl - S2
7) ~1 - (S/B)l - Bl - (S/B)2 - B2 - (SjB)3 - S2
- 8) Sl - (S/B)l - S2 - (S/B)2 ~ Bl - S3
Z 9) Sl - (S/B)l - Bl - S2 - ~2 - ($/B)2 S3
10) Sl - (S/B)l - S2 ~ Bl - tS/B)2
11) 'Sl - (S/B)l - S2 - (S/B)2 - Bl
The present method is carried out by way of
multistage polymerization. In each stage, addition of
the monomer may be conducted a-t any time after the con-
version in the preceding stage has reached substantially
100 %. In the present method, it is possible to obtain
an overall converslon of substantially 100 %.
In the present method, the mean molecular
- 12 _
105~)~91
1 wei~ht of the block copolymer resin to be formed is
regulated by the amount of an initiator used. Accord-
ing to this invention9 the mean molecular weight of
the block copolymer should have a value in the range
from 0.35 to 1.8 dl/g in terms of intrinsic viscosity
{~ , as measured in toluene at 30C. A block co-
polymer of low molecular weight, which has an intrinsic
viscosity below 0O~5 dl/g~ is undesirable because of
decreased mechanical properties 9 while a resin of ex-
cessively high molecular weight, which shows an intrinsic
~iscosity exceeding 1.8 dl/g9 is also undesirable be-
cause of deterioration in transparency and in pro- -
cessability.
The polymerization according to this invention
is carried out at a temperature from -20 to 150C.,
prefe~ably from 20 to 120C. The polymerization
pressure is selected from those which are sufficient
to keep the monomer and solvent in liquid phase at
~ the polymerization temperature. A sufficient poly-
merization time is 1 to 48 hours, usually 1 to 24
hours, though depending on polymerization conditions.
After the polymerization is completed, to
the polymerization mixture is added sufficient amount
of water, methanol, ethanol, or ispropanol to deactivate
the active terminal of the polymer and the residual
initiator. After adding, if necessary, a small amount
of an antioxidant such as, for example, 4-methyl-2,6-
di-tert-butylphenol, the polymer can be precipitated
and recovered by use of an excess of methanol, ethanol,
or isopropanol. ~n alternative procedure is to recover
- 13
so~
1 the polymer by directly heating the polymerizate solu-
tion to dryness or by contacting the polymerizate
solution with steam to remove the solvent by distilla-
tion.
The block copolymer obtained according to
this invention can be processed by conventional pro-
cessing techniques to be used in the field where the
conventional resins have been used. The copolymer
can also be compounded with conventional stabilizers,
reinforcing agents, fillers, and various other addi-
tivesO
As mentioned in the for,egoing, the presentinvention provides a novel method for producing a co-
polymer resin, transparent and excellent in mechanical
propertie,s 9 from 90 to 65 parts by weight of a vinyl
aromatic compound monomer and 10 to 35 parts by weight
of a conjugated diene monomer, both used as starting
materials, by adding to the polymerizatlon system said
monomers in specified sequence and in specified combina-
tions using an organolithium compound as initiator. The
present method may be easily carried out on a commercial
scale and the resin obtained is characterized by trans-
parency and excellent mechanical characteristics so
that it may be used even in the field where conventional
resins could not be succe-ssfully used.
~ he invention is illustrated below in detail
with reference to Examples, but the invention is not
limited to these examples.
- 14
~1~5~
1 Example 1
Into a 2.5-liter glass autoclave provided
with a stirrer, after the air in which had been re-
placed by argon, were charged 1.5 liters of purified,
dried cyclohexane 9 1 17 g of tetrahydrofuran~ 125 g
of purified styrene 9 and a hexane solution containing
6.5 millimoles of n-butyllithium. The autoclave was
externally heated to 60C~ to conduct the first stage
polymerization for one hour. Into the autoclave was
then added under an argon pressure a mixture of 125 g
- of styrene and 75 g of butadiene~ continuously for a
period of about 2 hours to con-tinue the second stage
polymerization for 3 hours in total. Then, 50 g of
butadiene was added into the autoclave to continue
the third stage polymerization for one hour. After
addition of another 125 g of styrene, the fourth stage
polymerization was carried out for 1.5 hours~ hfter a
total of 6.5 hours 9 the polymerization ~as terminated
by addition of 50 ml of methanol as terminating a~ent.
The resulting solution was poured into a large amount
of methanol to precipitate a polymer. The polymer
obtained in a yield of 98.5 % had an intrinsic viscosity
~ of` 0.68 dl/g, as measured in toluene at ~0C.
A mixture of 100 parts by weight of the polymer, 005
part of 4-methyl-2,6-di-tert-butylphenol and 0.5 part
of tris(nonylphenyl) phosphite, both used as antioxidant,
was pelletized by means of an extruder and the pellets
were injection molded to prepare specimens for testing
physical properties. The molded specimen had an
attractive appearance and a hi~h transparency~ The
- 15 -
., ..... .. .. .. , ..................... . .. .. _.~,~
50~L9~
1 results of test were as shown in Table 1.
Table
_ . .
Intrinsic viscosity(l), dl/g 0.68
_ __ . _ .
Melt index(2) 9 g/10 minutes 1.96
_ _ _ _ .
. Tensile strength (yield point)(3), kg/cm2 171
, _ __ _ . _ _ .
Tensile strength (breaking point)(3), kg/cm2 239
Elongation(3), ~o 359
~ .
Izod impact strength(4) 9 Xg-cm/cm2 > 100
. _ _ __
Haze value(5), % 7.5
.
~ote: (1) Measured on the polymer before pelleti~ation,
ln toluene at 30C. by means of an Ubbelohde
viscometer.
(2) Measured according to JIS K 6760.
. (3) Measured according to JIS K 6871 at 20C.
and at a speed of testing of 5 mm/minuts.
(4) Measured according to JIS K 6871 on un-
. notched specimens at 20C.
(5) Measured according to ASTM D 100~.
Examples 2 to 4
Polymerization was conducted by use of the
same apparatus and in the same manner as in Example
1, except that combinations o~ the monomers were as
shown in Table 2. In each Example, 1.17 g o~
- 16 -
~.
iOSOi9~L ~
1 tetrahydrofuran were used as the ~ewis base com-
pound.
,
.
': . '
. . .
, . . . .
. ~ ~
. . .
, . . :
.
'
,
'
~, 17
\c
~L~50~1
_. _
. ~ ~ .
. O ~ ~ r .~
~ ~, O ~J N ~J . ..
O ~0 .
'~- ' '~h~a~ _
'~ O O O .
h ~ h ~ h
--- O O O, . ''
~ j h o~ ¦ ~ ;
E~ _
. '~bD ~DC =~ ~ : ' .
O ~ rl
~ ~ ~ o rd
. _ U~ ~ l ~Q ~
. 1::- O O O
- -
. ~æ N 1~ _
.: . .
~os~9~l
1 ~ The polymer obtained was treated in the same
manner as in Example 1. Results of test for physical
properties were as shown in Table ~.
.. . .
19
D5~:SL9~
., ~ ,
' . ~_
..
P~ o o o
~ r-- ,0~ N
N
. -- _ .
~ ~ ~ U~ O O
O C~ St ~ IS~ O O . ..
N ~ ~1 ~_1
H ~h
.~ A ~
, __ _ _
. ~ .
~ N d t~
O . ,
. . , ~ _ , _.
, ~, ~-~1 ,U~
. h E3 ~1 ~
~a c) .
~1~ ~.~ c~ o. .
~--1 '~ N N 1--l
_
C.) h .
rl ~
t'rl bD '
S~ l O O O
~t.~.
_ _ _
. r~' .
_
,
~s~
1 Example 5
In a manner similar to that in Example 1,
five.-stage polymerization was carried out using the
monomer combination as shown below. Polymerization
in the second and fourth stages was conducted while
feeding the monomer mixture under an argon pressure
continuously for a period of 1.5 hours. The amounts
of tetrahydro~uran and n-butyllithium were the same
as in Example 1.
Monomer in the first stage: Styrene. 125 g
Monomer in the 2nd stage: Styrene 62.5 g
Butadiene 37.5 g
Monomer in the 3rd stage: Butadiene 50 g
Monomer in the 4th stage: Styrene 62.5 g
' . . Butadiene 37.5 g
.Monomer in the 5th stage: Styrene 125 g
. . The polymerization procedure in Example 1
. was ~ollowed and the polymerizate obtained was treated
.
in the same manner as in Example 1. The results of
.,test for physical properties were as shown in Table
4.
`~
.
- 21 -
91 ' .
1 ~ Table 4
Int,rinsic ViSCos1ty, dl/g 0.69
Melt index, g/10 minutes 0.91
Tensile strength (yield point)~ kg/cm2 205
Tensile strength (breaking point) 9 kg/cm2 2~3
Elongation, % ' 384
. Izod impact strength9 kg~cm/cm2 > 100
Haze value 9 % . 9 5
~ . _
Examples 6 to 8
Polymerization was carried out in the same
manner as in Example 5, except that the monomer com-
binations used were,as shown in Table 5. ~he amountsof n-butyllithium (as initiator) and tetrahydrofuran
ewis base compound) were the same as in Example 5.
: : .
~ - 22 -
- '~
~SO~IL9~ .
' ~o o o o .`
h :1 ~ ~ .a~
:~ P. ~ ~ .
U~ ~ ~ .
,. .~ 00 ~t-
~ ~ 3 ~ 3
O ~ S~ Cd S-l ~ S~ ~
~: ~ ~ ~ ~: v~ m . `
~ o--o ~ ':
. L 'a . ~ ~
U~ 1~ _-- ' CU
~ ' Il~ U~ . I
' -~ bD LL~ C- ~ GO r-
~ ~ ~ ~ ~ V~ ~
~ ~ o lo o
`:
~ ~ ~ ~
.`
æ~ f~ ~
.. __
aO ~D ~ 0 .
~ .
10501~
1 . The polymerizate obtained was treated in the
8ame way as in Example 1. The results of test for
physical properties were as shown in Table 6.
.... .
: , .
-
.
: -
:`: ~ . : :
,
'~ : ` ',.
, ` . : .
.
.
.
'
.
.
: ; - 24 -
~!5~9~9~
''. Q)~ . _
. ~ o ~ U~ , .
a)~ ~
N
_ _ _ _ , l
,~ ~ , ,siE~ ~D 'cn o .'
C~ ~ ~ ~ ~ O
O ~ .
N p~ ~ . .
H ~ ~ ~ .
_ _
r~
~ . N t~ l
~1
~O
U~ ~ ~1 Ir~ O t~ C~J '
h~,, P.
rl ~ a) ~ O N d-
~ ~1 o cr~ 1
E-l P-~ ~ N N
_
~. , .
. . rl ~ .
~ ~ bD C- ~ ~
~C)~~ O O O
H ~
' ~
~1
~ O ~O ~ OD
`_.~ _'
. .
1~50:~9~ -
1 Examples 9 and 10
Polymerization was carried out in the same
manner as in Example 1, except t`hat the monomer com-
binations were as shown in Table 70 As the ~ewis
base compound, 009 g of tetrahydrofuran was used.
.
_
- - 26 -
~05~9~ -
~ . . _
~3~ D
' ~
_ _
~bO ~0 O ~ .- .
~ ¦ a~ ~D ¦ a a ¦ a ~, ¦
H 9 N r N
~` ~ ¦ a ¦ a j- a ¦;
~1
_ - I '
~ ~__
~50~1
1 The polymerizate obtained was treated in
the same manner as in Example 1. The results of
test for physical properties were as shown in Table
8~ -
,. .. : .
. ~
:
,
.. .
- 28 -
50~L9~ -
'. I ~.~.. ~ ~ 1
~ ~
. N ~ h ~ -
~ ' . '
O ~ ~O ,
~0 1~1
~ a~ a ~ ~1 ~
~1 Fq ~
. a ~ a
C)P~ .
cq.,~ b~ O ~
.~ o ~ O O
. o
_ _
~oso~
1 ~Example 11
In the present Example 9 oligoisoprenyldi-
lithium compound was synthesized in the following
manner and used as an organolithium compound of the
both-ends initiation type.
Into a 300-ml four-necked flask, after the
air in which had been replaced with argon, were charged
50 ml of purified tetrahydrofuran and 0.35 g (0.05 mole)
o~ dispersed metallic lithium~ Into -the flask was
added with stirring 6O4 g (0.05 mole) of naphthalene
dissolved in 150 ml of tetrahydrofuran through a
dropping funnel and allowed to react for 24 hours.
To the reaction solution, after having been cooled
.. . .... .
to -40 to -50C., was added gradually 40 ml of
isoprene with a period of about 6 hours. Thereafter,
the flask was warmed slowly to room temperature and
further heated under reduce pressure to remove tetra-
hydrofuran by distillation. The contents of flask
~ere dissolved by adding 400 ml of purified benzene,
and the resulting benzene solution was subdivided into
small portions and stored in ampoules to be used later
in polymerization.
The polymerization according to this invention
was carried out by use of the same apparatus as in
Example 1 in the following way.
Into the reactor, were added 1.5 liters
of cyclohexane, 0.9 g of tetrahydrofuran, 50 g of
. ~ .
_ 30 -
~1~5~L9~
1 butadiene, and 120 ml of oligoisoprenyldilithium
initiator solution, and allowed to react at 60C~
for 2 hours. To the reaction mi~ture9 was added
continuously a mixture of 125 g of styrene and 75 g
of butadiene to continue the polymerization for 3
hoursO Then9 250 g of s-tyrene was added and poly-
merization was allowed to proceed for 1.5 hours.
After termination o~ the polymerization9 the poly-
merizate mixture was treated in the same manner as
in Example 1. Physical properties of the polymer
obtained were as shown in Table 9
Table 9
_ _ . . I -
Intrinsic viscosity, dl/g - 0.73 .
Tensile strength (yield point), kg/cm2 197
Tensile strength ~breaking point)9 kg/cm2 228
Elongation, % ~72
I~od impact strength9 kg.cm/cm2> 100
Haze value, % lO.S
.
Comparative Examples 1 to 4
Polymerization and after-treatment were carried
out in the same manner as in Example 19 except that the
combinations of monomer and a I.ewis base compound were
as shown in Table 10. The results obtained were as
shown in Table 11.
- 31 -
1~5~L9~iL
_ _ = _ _ ~
-q~ ~ 3 ~ ~
,, o 0 o o ,~ ,,
V V ~ ~
_ ___ o O O h o
__ æ ~ h O h h
~I> ~ \ \ ~ ~
. a~D \ \ ~" s~
_ _
~ ^ o o o o ~ o
O~ h ~ ~ d s~ s:~
,. ~ o~ :~ ~ ~ 01
E~ ~ U~ U~ ~ U~ ~
.~ '. . . ~ O O- O O--
~ ~ ~D ~ rl rl rl
~ N _ ~1 ~q Irl
_ o o o a~
h ~c~l cu r-l ~1
a~ ~ a) a) ~
~D ~I :: ~ , ~:
~- _ _
"a _ _ _ ~
.
.. .
1050~91
'' ~.. ~'
__ _
? ~
N
H
__
rl .
~1
~ ¦ - l !
,~.
~ ,~
o :~, .
W~I I
. _ .
~ P ~ ~ C~ '
~ ;
_~ ~ . _ .
. , ..... .,.~,~.. _
1 As is apparent from Table 11, those block
copolymers which have in the molecule an elastomeric
block composed of polymerized conjugated diene alone 7
are inferior in physical properties (Comparative
5 Examples 1 and 2). It was also found that when the
monomer mixture was added all at a time and poly-
merization was carried out in the absence of a ~ewis
base compound such as tetrahydrofuran, mechanical pro-
perties of the resulting polymer become markedly
10 inferior (Comparative Example 3). It was further
found that a block copoly~er having elastomeric blocks
in which the copolymerized conjugated diene and vinyl
aromatic compound segments occupy less than 50 ~ by
weight is inferior in mechanical properties to the
15 block copolymer prepared according to this invention
(Comparative Example 4).
: ' . .
~xample 12
~ Into a 2.5-liter glass autoclave, after the
20 air in which had been replaced with argon~ were charged
1~5 liters of purified, dried, and deaerated cyclohexane
and i50 g of styrene. A n-butyllithium solution diluted
with n-hexane to a predetermined concentration was
added dropwise into the stirred autoclave until a pale
25 orange color characteristic of a polystyryl anion
appeared. Thereafter, 6.5 millimoles of n-butylli~hium
was added as an initiator into the autoclaveO The
- autoclave was heated to 100C. and stirrin~ was con-
- tinued for one hour. ~ mixture prepared from 50 g of
30 styrene and 30 g of purified dry butadiene was added
34
1 to the polymerization system, maintained at 100C.,
continuously at a rate of 1 g per minute. After the
addition, stirring was continued for 30 minutes. `t'
Then, 40 g of butadiene was added and polymerization
was continued for one hour. To the polymerization
system was further added a mixture of 50 g of styrene
and 30 g of butadiene continuously at a rate of 1 g
per minuteO After the addition 9 stirring was con-
tinued for ~0 minutes and then 150 g of styrene was
added to continue the polymerization for further one
hour at 100C.
The polymerization was terminated by addi-
tion of 50 ml of methanol and the resulting poly-
merizate solution was poured into a large amount of
methanol containing 4-methyl-2,6-di-tert-butylphenol
as antioxidant, to precipitate a polymer. The pre-
cipitated polymer was collected by filtration and
dried in vacuo to obtain a dry polymer in a yield of
98.6 ~. The polymer had an intrinsic viscosity ~ of
0.70 dl/g, as measured in toluene at 30C. A mixture
of 100 parts by weight of the polymer, 0.5 part of
4-methyl-2,6-di-tert-butylphenol and 0.5 part of
tris(nonylphenyl) phosphite, both used as antioxidant,
was pelletized by means of an extruder. The pellets
were injection molded to prepare specimens for testing
physical properties. The molded specimen had an attrac-
tive apperance and a high transparency. The resul-ts of
test were as shown in Table 120
- 35 -
~050~L91
1 Table lZ
. . . _. _
Intrinsic viscositytl), dl/g 0.70
Melt index(2) 9 g/10 minutes 0.81
Tensile strength(3), kg/cm2 279
Elongation(3) 9 % 220
Izod impact strength(4), unnothced 9 kg - cm/cm2 45.0
Flexural stress clouding , mm 3.3
~lass transition temperature(6), C. -58
. _ _ _ __ _
~ote: (1) Measured on the polymer before pelletization,
i~ toluene at 30C. by use of Ubbelohde
viscometer.
(2) Measured in accordance with JIS K 6760.
1 (3) Measured in accordance with JIS E 6871.
(4) Measured in accordance with JIS K 6871,
at 20C., unnotched.-
- (~5) ~ specimen9 38 mm 2 13 mm, was cut out
o~ a press-molded sheet, 1 mm in thickness,
and annealed at 80C~ for 3 hours. ~he
annealed specimen, without incision, was
mounted on a holder specified in JIS Z 1703,
left standing ln the air at room temperature
for 24 hours and the width of cracks dis-
tribution developed due to the stress was
measured.
(6) Calculated from the kinetic viscoelasticity
data as a function of temperature.
36 -
' ' '' -'"'`''~F
~s~
1 iExamples 13 and 14
. Polymerization was carried out in the same
manner as in Example 12, except that monomer combina-
tions were as shown in Table 13.
,.... ...... ~
1~50~
- - - o
'~ b~ ,~ ,~
S~ ~d a) ~
~ ~ ~ . i ~
~ ~ h
_
~ , U~ U~
N 1~ C-- i~
5 bD ~ , t~ ~
~ ~ ~ a) .
¦ i~ ~ ¦ h :~ h ~ ¦ ;
, . _
'~'~0` ~ U~ .
El ~q bD ~ - ~1
G~ ~ ~ ~ . ~ I ~
~1 _ 00
E~ . L~ Ll~
t~ c- c-
s~ ~ ~ t-~ ~
,. El~qbD ~I~ s:~
s:: ~ a) ~ Q) ~ ~ ~
, ~:~ ~ ~ ~ ~, '
O '
h 0 . ~1
'o~ ~ ~ .
~1 ,~ ~ ~ .'
~- ~ ~
X~; . .,. , '';
.
. .
. .... .... ... _.
~)5(~1g~
1 The polymerizate obtained was treated in the
; 5ame manner as in Example 12. Phys~cal .properties o~
the polymer were as shown in Table 14.
'
.. :
,
, , , -
:~
; . _ 39 -
:
...... - ~-
,..... _ _ .
,..... - ' ~ ~ .
~: h ~Q bD t~ O
~ . ~
$~ J
~1 :
c) ~
~ ~ O t~
~ ~\
H U~ Yl
' ~ _ . .
-1 '~
. ~ .
C ~ Uo~ ,~ ~
. ~ 5: h ~ c~ J
. -- -
L . ~ ~
' ' . ~0 O O
' __
.
. ' ~ 0
H P O O
~ I .
t~ ;~j ..
.. '. . ~. ' '
;. :
.. _ ... ~r~
9LQ50~9~1L
1 ~Example 15
In a manner similar to that in Example 12,
four-stage polymerization was carried out by use of
the monomer combinations shown below. Polymerization
in each of the first, third, and fourth stages was
conducted for one hour. The copolymer segment of
styrene with butadiene was formed in the second stage
while feeding the monomer mixture continuously at a
rate of 1 g per minute.
1~ . .
~onomer in the first stage: styrene 150 g
Monomer in the second stage: styrene 100 g
butadiene 60 g
Monomer in the third stage: butadiene 40 g
Monomer in the fourth stage: styrene 150 g
The amount of n-butyllithium used as the
initiator was 6.5 millimoles. The polymerizate obtained
was treated in the same manner as in ~xample 12. ~he
results of test physical properties were as shown in
Table 15.
Table 15
Intrinsic viscosity, dl/g 0.71
Melt index, g/lO minutes 0.55
Tensile strength, kg/cm2 258
Elongation, % 213 ~
Izod impact strength, unnotched, kg-cm/cm242 0
Flexural stress clouding, mm 3.1
. : . -
41 -
D
105~
1 Example 16
. In a manner similar to that in Example 12,
seven-stage polymerization was carried out by use
of the monomer combinations as shown below.
5Monomer in the first stage: styrene 150 g
Monomer in the second stage: styrene 25 g
butadiene 25 g
Monomer in the third stage: butadiene 25 g
Monomer in the fourth stage: styrene 25 g
10butadiene 25 g
Monomer in the fifth stage: butadiene 25 g
- Monomer in the sixth stage: styrene 25 g
. - ~ butadiene 25 g
Monomer in the seventh stage: styrene 150 g
' The amount of the initiator used was 6.5
millimoles 9 as in Example 12. Polymerization was con-
ducted for one hour in each of the first and seventh
stages and for 30 minutes in each of the third and
fifth stages. In the second and fourth stages, the
monomer mixture was continuously fed at a rate of 1 g
per minute. In Table 16 were shown physical properties
of the polymer obtained after the treatment similar to
that in Example 12~
,
`
1~5C7~L91
1 Table 16
, . . .
Intrinsic viscosity, dl/g . 0.70
Melt index, g/10 minutes 0.60
Tensile strength, kg/cm2 23~
Elongation, % . 297 .
Izod impact strength, unnotched, kg cm/cm2 50.3
Flexural stress clouding, mm 4.6
.
: Comparative Examples 5 to 8
.
Polymerization was carried out in the same
manner as in Example 12, except that the monomer com- :
binations and methods of feeding monomers in forming
the copolymer segments of styrene with butadiene and
. the homopolymerized butadl.ene segments were as shown
- in Table 170
- .,
.
. . 43
~LOS~
_
F~. a) ~ O ~ a) Q) h O
Q) Q) ~ c) I ~ ~ 'H ~D
h ~ O O +' ~d ,~ ,~h Q) O o ~
h ~ E 'd El h::~ O bO +' a) ' o h
El ~ bD ~3 rd ,D ~ . tn :~ ~3 rd
O ;~D O ~ Q~ a) ~ ~ r~ . Q cd
'~ -~H Q> ~ ~H c~ ~ E3 ^~H
~ a C~ ~d 5~ c~ ~ ~D ~ O ~ ~1
O ~H S:~ ~ +~ ~: ~ +~ C) (D ta cd t~i +~
, ~ . O~ ~ E3 sl 'H ~ ~ ~ o E3
Q~ ~ ~ Q~ o X ~ bD~ ~ ~ ~ ~ ~ s~
~ ~rl ,D t~ ~ H 3 +~ ~1H ;~ ~d H ~ ~ H E3 ~ ~ .
_
~^ g O O
~ ~J rl l
. ~bD .1 ~ S:~ Q~
h h U~ h
~_ ,01 ,01~ 00
. E3 ~ l Q) ~ ~ Q
. N +~ ,Q) ~d h
. ~q ~ ~ ~ m
: _ _ .
~ o $ $ o o~
~-1 d- ~--I N ~--I ~1
h
3 ~q bD d s~ S:
--I :~ h ~ ' P~
V~ 1~1 U~ U~ V~
. _ _.
P
.
h ~ ~2; If~ ~ t--
~ . .
C~ . .
_ _ _
'
105~91
1 -After having been treated in the same manner
as in Example 12, the polymer obtained was tested for
physical properties. The results obtained were as
shown ln Table 18.
. "' , '.
.
,
. I~5
S~
_ . _ _
,,.. -. .
, .~ ..
~ U~ ~ ~ . W L~ I
:, ~ V ~ ~ 0~ 1
~1 u~ a) o
C~ .
, _ _ _ __
s~ ~
r~ ~ O ~ ~, ~ N
X Ql ~ ,!d~ l
~D ~ O O
C~ ~d
_ .
O U~
~bD~ O t~ ~ O .
o ~ E~ O r~ O
C~ ~> C) ~ ~
O ~ S~ ~
_ ,
,CD 1~ .
,D O O vt ~ d I ~ ~
E-~ . _ . _
. ~ ' 'I ~ O t~
~1 ~ ,
E~ 1 ~ 0~ '
. _ _ . :
..
a~
. ~'~ ~ C~
.. ''10 ~I ~ o ~
~'l ~i o o ~ .,
~:~
. . _
oP.
d o~ w Lr~ ~
~ O, o o o
H P .
__ '.
~ ~1 .
~, o .
. ~r~ ~ O U~
~ ;
C~ F~l ~ _
o ` . ... . ,.~
Sl~iL9~L
1 It is seen from the results that if the co-
polymer lacks in homopolymerized styrene block, as
in Comparative Example 5, tensile strength of the
resin becomes markedly low, while if in the second
s~tage butadiene was homopolymerized or styrene and
butadiene were copolymerized to form less randomly
copolymerized segment by feeding the monomer mixture
all at a time, as in Comparative Examples 6 and 7,
the resulting block copolymers become lnferior in
elongation and impact strength9 and more susceptible
to flexural stress clouding. Therefore, such copoly-
mers are undesirable.
On the other hand, if in the second stage
styrene and butadiene were randomly copolymerized by
continuously feeding the monomer mixture and no homo--
polymerized butadiene segment was formed, as in Com-
parative ~xample 8, the resulting polymer becomes
~uperior in impact strength and less susceptible to
flexural stress clouding, whereas the glass transi-
tion point becomes higher, indicating deterioratedmechanical properties at low temperatures.
; 47 -
. ~ r~
