CA1050185A

CA1050185A - Butadiene based transparent thermoplastic mixtures of resins

Info

Publication number: CA1050185A
Application number: CA232,035A
Authority: CA
Inventors: Minoru Tabana; Tatsuyuki Mitsuno; Hiroshi Maki
Original assignee: Sumitomo Chemical Co Ltd
Current assignee: Sumitomo Chemical Co Ltd
Priority date: 1974-07-23
Filing date: 1975-07-22
Publication date: 1979-03-06
Also published as: JPS5112859A; JPS534861B2; GB1509972A; FR2279807A1; FR2279807B1; DE2532741A1

Abstract

ABSTRACT OF THE DISCLOSURE
A resin composition consisting essentially of a block copolymer resin of styrene and butadiene and a liquid homopolymer or copolymer of butadiene or a modified product of these liquid butadiene polymers. This resin composition is transparent, excellent in elongation and practical strengths, resistant to flexural stress clouding, and has excellent hinging characteristics. The resin composition is suitable inter alia for sheeting and film.
.theta.

Description

~CI SOll~S
1 This invention relates to a thermoplastic resin composition. More particularly, it relates to a thermoplastic resin composition which is transparent, excellent in mechanical properties, particularly in elongation and practical strengths, and resistant to flexural stress clouding~ and has excellent hing-ing characteristics~ said resin composition consisting essentially of a block copolymer resin of styrer.e and butadiene and a liquid butadiene polymer or copolymer or a modified product thereof, such as, for example, a low-molecular-weight homopolymer of butadiene or a low-molecular-weight copolymer of butadiene with styrene~ or a modified product of these liquid butadiene polymers with maleic anhydride or by epoxidation.
Although excellent in transparency, elonga-tion~ and impact strength, resistant to flexural - stress clouding, and having excellent hinging charac- ir teristics, conventional styrene-~utadiene block co-polymers have presented a problem of inferior strengths of practical significance.
The present inventors have now found that i~ order to markedly improve the impact strength of a styrene-butadiene block copolymer resin without deteriorating other characteristic properties thereof~ ¦
it is very effective to incorporate therein a liquid butadiene homopolymer or copolymer~ or a modified product of these liquid pol~ners (hereina~ter referred to simply as liquid polybutadiene resin).
An objcct of this invention is to provide a composition conS:istirlg ess~ntially Or a styrene _l_ ~ ' :
.

:~50~8S
1 butadiene block copolymer resin and a liquid poly-butadiene resin; said composition being excellent in transparency and elongation, resistant to flexural stress clouding~ and having good hinging characteristics and excellent practical strengths.
Although the reason for the retention in the present composition of the transparency in~erent to the styrene-butadiene copolymer is yet to be elucidated, it seems that the transparency is the result of so uniform a dispersion of the liquid polybutadiene resin in the styrene-butadiene block copolymer resin that the former can no longer be recognizable as a dispersed phase upon observation ~ of the microstructure by means of an electron micro-scope.
- ~ The invention is explained below in detail.
The styrene-butadiene block copolymer resin for use in this invention is that obtained by polymerizing in an inert solvent 65 to 90% by . .
weight of styrene and 10 to 35% by weight of butadiene in the presence of a polymeriz~tion initiator of the organolithium type. Depending on the mode of addition of styrene and butadiene~ varlous blocks can be formed. A preferable block copolymer is repr~sented by the general formula, Al - Bl - C - B2 - A2 t (wherein Al and A2 are non-elastomcric blo-ks com-prising a polymerized styrene chain; Bl and B2 are elastom~ric blocks comprising a random copolymer

2 --~L~50~1~S
1 chain in which styrene and butadiene are uniformly distributed; C is an elastomeric block comprising a butadiene homopolymer chain or a styrene-butadiene eopolymer chain; the proportion of the sum of Al and A2 in the block copolymer is 40 to 80% by weight;
the proportion of the sum o.f Bl and.B2 in the block copolymer is 10 to 60% by weight; the proportion of C in the block copolymer is 0 to 25% by weight and is always smaller than the proportion of the sum of Bl and B2; the weight ratio of Al to A2 is in the range from 2/8 to 8/2; the weight ratio of Bl to B2 is in the range from 0/10 to 10/0; the weight ratio of styrene to butadiene in Bl and B2 is in the range from 10/90 to 75/25; and the weight ratio of styrene to butadiene in C is in the range from 0/100 to : 1~/90) and has a total styrene content of 65 to 90%
by weight, a total butadlene content of 10 to 35% by weight, and an intrinsic viscosity of 0~.35 to 1.8 .dl/g as measured in toluene at 30C.
Of the liquid butadiene polymers, that is, low-moleeular~weight homopolymers of butadiene~ a polymer containing a major amount of 1,4-cis eonfigura-tion is obtained in the presence of a.Ziegler catalyst such as a catalyst system comprising an organo-aluminum compound and a niekel eompound; a polymer containing a major amount o~ trans configuration is obtained by polymerization of 1~3-butadiene in the presence of a transi-tion metal catalyst system o~ the Ziegler type or a radiçal polymerization initiator; and a polymer cont~ini.ng a major proportion ~50~85 1 of 1,2-vinyl configuration is obtained by polymeriza tion of l,3-butadiene with a polymerization catalyst system comprising an elementary alkali metal or an organoalkali-metal compound. The average molecular .
.weight of these liquid polymers is 300 to 10,000, preferably 1~000 to 7~000.
The low-molecular-weight copolymer of -. butadiene and styrene is obtained by polymerizing 40% by weight or less of styrene and 60% by weight or more of butadiene with a catalyst system of the Ziegler type and has an average molecular weight of 300 to 5,000.
, . The low-molecular-weight homopolymer of butadiene modified with maleic anhydride is obtained 15 preferably by modifying a low-molecular-weight ~ ~.
butadiene polymer having an average molecular weight : . - of 250 to 5,000 with 20~ by weight or less of maleic anhydride.
~he low-molecular-weight butadiene homo-polymer modified by epoxidation is obtained by epoxidiæ-ing a low-molecular-weight butadiene polymer having an average molecular weight of 250 to 5J000 with an organic peracid such as performic acid or peracetic acid and has an oxi~ane-oxygen content of preferably 0.5 to 20% by weigh-t.
Although the liquid polybutadiene resin .- content of the present composition is generally 1 to 30~ by weight, the most effective content for improving the practical strengths without deteriora-tion in transparency of thè styrene-butadiene block ~ 85 1 copolymer resin depends upon the structure Or the liquid polybutadiene resin. The liquid tlow-molecular-weight) butadiene homopQlymer among the liquid poly-butadiene resins gives good transparency and markedly improved impact strength when its content of the present composition is 3 to 27% by weight, the specimen becoming unbreakable in the Izod impact test particularly when the content is 10% by weightO If the content is below 3% by weight~ the improvement in impact strength is insufficient, while if it exceeds 27% by weight, the transparency decreases to some extent and also the impact strength rather decreases. Such tendencies are generally recognizable when a liquid (low-molecular-weight) butadiene homopolymer contains a major amount of 1~4-cis configuration~ trans configuration, or 1,2-vinyl configuration.
The liquid (low-molecular weight) copolymer of butadiene and styrene gives a composition excellent in both transparency and impact strength when its content of the composition is 3 to 27~ by weight. If the content is below 3% by weight, the impact streng-th is unsatisfactory, while if it exceeds 27% by weight, the transparency becomes decreased.
The liquid (low-mo~ecular-weight) butadiene 2~ polymer modified with maleic anhydride gives a com-position having good transparency and excellent impact - strength when its content is 2 to 12% by weight.
If the content is below 2% by weight, the impact strength is unsatisfactoIy~ w~lile if it excecds 12%
by weight, the transparency is considcrably decreased.

~LID51[)~L85 1 The liquid (low-molecular-weight) butadiene polymer modified by epoxidation gives a composition having comparatively good transparency and excellent impact strength when its content of the composition is 2 to 10% by weight. If the contént is below 2% by weight, the impact strength is unsatisfactoryg while if it exceeds 10% by weight, the transparency becomes markedly inferior.
Blending of the styrene-butadiene block copolymer and the liquid polybutadiene resin may be effected by use of customary mixing equipements such as a mixing roll mill9 Banbury mixer~ and extruder.
Since the present thermoplastic resin composition thus obtained is excellent in transparency and elongation, resistant to flexural stress clouding, and has good hinging characteristics and improved practical strengths, it is really suitable for use as a material for sheeting and film.
The present composition can be incorporated with a plasticizer such as widely used phthalate esters and dibasic aliphatic acid esters.
The invention is further illustrated below in detail with reference to Referential Example and Examples.

Referential Example Preparation of the styrene-butadiene block copolyme`r for use in this invention was carried out in the following manner.
Preparation of styrene-butadiene block ~os~g85 1 copolymer A:
Into a 25-liter autoclave provided with a stirrer and a jacket, which had been flushed with nitrogen to replace the air, were charged 15-liters of dried cyclohexane as solvent, 1.25 kg of styrene, 9.0g o~ tetrahydrofuran, and a n-hexane solution containing 75 millimoles of n-butyllithium as initiator.
The polymerization was started and after 1.5 hours o~ polymerization at 60C a second-stage monomer .
mixture of 1.25 kg of styrene and 1.25 kg of butadiene was added. The polymerization was continued for further 3.0 hours at 60C. ~hen~ 1.25 kg of styrene was added as a third-stage monomer and thé polymeriza-tion was continued for ~urther 1.5 hours. The poly-merization was terminated by addition of 50 ml of ethanol. The resulting viscous polymerizate solution was mixed with a large quantity of methanol with . .
vigorous stirring to precipitate a polymer which was collected by filtration and dried in vacuo. The polymer, which was obtained in a yield of substantially 100%~ showed on analysis an intrinsic viscosity of 0.74 dl/g as measured in toluene at 30C~ a butadiene content of 25% by weight, and a melt i.ndex (JIS K 6760) of 0.5 g/10 min. as measured at l90C and under a load of 2.16 kg.
Preparation of styrene-butadiene block copolymer B:
The above procedure was repeated, except that 1~50 kg of styrene was used as the first-stage monomer; a second-stage monomer mi~ture of 375 g of , - ~ ~05~185 styrene and 375 g of butadiene was added at a constant rate over a period of 1 hour; 500 g of butadiene was sdded as the third-stage monomer and polymerization was continued for 1 hour; a fourth-stage monomer mixture o~ 375 g of styrene and 375 g of butadiene was added at a constant rate over a period of 1 hour;
and polymerization was continued after addition of 1.50 kg of styrene as a fifth-stage monomer. There was obtained a polymer having an intrinsic viscosity of 0,76 dl/g9 a butadiene content of 25% by weight, and a melt index of 0O30 g/10 min.

Example 1 ~ ' Compositions were obtained by mixing on a 8-inch roll mill at a roll-surface temperature ,15 of 150C for 10 to 15 minutes prescribed amounts of the styrene'-butadiene block copolymer A obtained in ' Referential Example and a liquid high-cis poly-butadiene having an average molecular weight of

3~000; a liquid 1~2-polybutadiene having an average molecular weight of 1~000; a liquid styrene-butadiene copolymer having an average molecular weight of 1,000 and a styrene content of 20%; a liquid high-cis polybutadiene having an aver~ge molecular weight of 520 modified with 5% by weight of maleic anhydride; or a liquid high-cis polybutadiene having an average molecular weight of 520 modiI'ied by epoxi-- dation to contain 9c5% by weight O.r oxirane-oxygen.
The compositlons thus obtaine,d were molded by compres-sion to yie]d pr~scribed test sp~cimens for physical ~CI 56)18~
testsO
The results obtained were summarized in Table lo ' ' '' `' ~ , ' ' ' ' ' ' ' ' "

' . '~ ' :

.

.
: ' . ' ~' , .

.. . .

~ 9 _ U~
C~ t ~- o ~ o o~ C~ CO C~ 0 CO ~ o~
C) ~ ~ .. ..
_~
. . - . .
G) O O O O C O O O O O ~
, .,, ~ ~ ~.o ~ (U o o o o ~ o o ~:
u~ ~ h ' H ~ .l O ~ 0 ~D O
b~ ~ ~J
h a~ --~
-. ~ ~ ~ O ,~d O ~ ,~4 0 ~ O
C) ~ O ~ ~ O ~ ~ ~
a~ c ~l ~ h O ~ h ~ _:t h O
H.,l u~ 3 ~ ~ ~
__ ~ ~ o ~ o r~ ~. o ~ ~ orl ~ -- - - - - --~ ~ :
,~ ~ l ,, a) , ,~ :
a~ ~ . ~ ~ ~ .
'r-~ ~ ~
ld ~' p~
............... ? .
P. I -- - P~ h h bD o C~ ~ h . ~ El .~
. . .,~ ' . ~
~'i ~ ~ .
,_ ~ ~ ~ ~ ~ O C' O ~ C`~ O ~ C' O
h n~ O O o~ 0~ ~ (~ C~ C' 0~ C~ r O P. ~1 ~ ~ O
ca ,o ~ c . _ ~ ~
O ~ N ~ ~ 1~ O
., _ . = = _ = . _ _ . ._ _ .

- .lO

.
- - ; ~ ~

~ N 11~ ~5) OJ O
oo o2) ~o Co oc) ~O .' .' . '' - _ . . ' .
.
~ . .
O O O O O O
~ O O ~ O O
. ~ ~ l _ __ _ .
. . . ~ . : :
.' O O' O ~ ~0 .
o ~ ~
~ O~ ~ ,~ =
~ . ' , .
= ~
. C~ J ~ O . ~ , .
. . ~ , ___ _ , ' . ~ ~ ' :
., C) ~
r-l rl :.
~': ' ~3 X
, 5:~ a) ~rl ~ ~
i~ = _ ~r~
~:1 h ~
a~
~rl ,~ ~I
~ rd .' ~0 ~0 . ~ ' _ .
.' .' . a~ ~ o o~
= . - __ ~ . .
. ~.
~ ~ ~ ~ ~ ~O
r~ ~ ~ ~I r~l r-l .
_~_ .

-- 11. -- .

`- ! iq~5018~
1 .~ Physical properties shown in Table 1 had been measured in the following way:
Izod impact strength: According to JIS
K 6871 (notched).
Energy of rupture in high-speed tensile test: Energy required to rupture JIS No. 3 dumbbell test specimen at a testing speed of 500 mm/minD
. Luminous transmittance: According to - ASTM D 1003 - 52.

Example 2 . ~
. . The procedure of Example 1. was followed, : . except that the styrene-butadiene block copolymer B
obtained in Referential Example was used. The resuits obtained were as summarized in Table 2.
- :
~. ' ' ~.
.

:

. , _. , U~ ~
.,, O a~
c~ ~ O~ ~ ~ ~ oo a~ t~ oo h a~
_ . ~
~ ~ .
m ~J h ~ ~3 O O O O O O O O O O O S:~
I ~ D C) 00 0 0 0 ~ O O r-l O 0 11~ 0 u~ ~ h ~ C~J VD ~ ~1 ~ OC~ N CC) ~1 t~
: ' bO~ ~
h a) `_ _ .
.. ,_ ' S:
O ~ ~0 0 0 ~ O ~ ~' O C) ~ ~ h ~ h ~ h h C~
O ~ bO
N U3 ~ P i~ P
H ~_ : -. . .
l O ~ O C` ~ O ~ ~ O' ~ C~
s:: ~ . ~ '`' ~1 '`J ~ '`' ~
,1 .
U~ ~ .
c~l a . h . .

.
. ~ .

. h O ,g ~ ,C
O

rl ~ bO N h a) ~ h U' h r l ~
~ '01 ~ ~
~ ~ 1:~' P. ~ tl~ , . ~
. . _ , I ~ 1~ .

O a) C.) h o c~ o ~ c~ o ~ C~ o ~ a:~
~ o o~ ~ C' ~ o~ C' o~ O~ C' O~
. ~ , ~1 0~1 ~1 0 ~n ,0 ~ p, _ __. _ ._ ._.__ _.. _.. ..... _ .. _ .. . . ._ ._ _ .__ .
O C' 0~ (S` O ~I C~ ~ ~ Ir~ ~C) C`
_ _.. ____ ~.. _._.. _.-___ _ _ .

, ~ O ~D ~ ~
o~ ~ .' -.
.-.
o o o o o o o o o o o ~o ~ ~ ~ . . .
C~ l . .
., _ . .. .
.

o o o ~
.
.
.__ . ...
. : ' co ~1N ~ O
.----_ .
.' , , . . . :
. C) ., a .~ . i' . ~
~ - P = =
h ~
,1 . .
~td' X

C~ ~ O

.

~ O~ O ,~ ~
tU ~ ~ ~

.

11 '

Claims

The embodiments of the invention in which an exclusive property or privikege is claimed are defined as follows:

1. A transparent, thermoplastic resin composition consisting essentially of a styrene-butadiene block copolymer resin and 1 to 30% of a liquid polybutadiene resin.

2. A composition according to Claim 1, wherein the styrene-butadiene block copolymer resin is re-presented by the general formula, A1 - B1 - C - B2 - A2 (where A1 and A2 are non-elastomeric blocks comprising a polymerized styrene chain; B1 and B2 are elastomeric blocks comprising a random copolymer chain in which styrene and butadiene are uniformly distributed; C
is an elastomeric block comprising a butadiene homo-polymer chain or a styrene-butadiene copolymer chain;
the proportion of the sum of A1 and A2 in the block copolymer is 40 to 80% by weight; the proportion of the sum of B1 and B2 in the block copolymer is 10 to 60% by weight; the proportion of C in the block copolymer is 0 to 25% by weight and is always smaller than the proportion of the sum of B1 and B2; the weight ratio of A1 to A2 is in the range from 2/8 to 8/2; the weight ratio of B1 to B2 is in the range from 0/10 to 10/0; the weight ratio of styrene to butadiene in B1 and B2 is in the range from 10/90 to 75/25; and the weight ratio of styrene to butadiene in C is in the range from 0/100 to 10/90) and has a total styrene content of 65 to 90% by weight, a total butadiene content of 10 to 35% by weight, and an intrinsic viscosity of 0.35 to 1.8 dl/g as measured in toluene at 30°C.

3. A composition according to Claim 1, wherein the liquid polybutadiene resin is a liquid butadiene homopolymer or copolymer thereof with styrene or a product thereof modified with maleic anhydride or by epoxidation.

4. A composition according to Claim 3, wherein the liquid butadiene is a homopolymer having an average molecular weight of 300 to 10,000.

5. A composition according to Claim 3, wherein the liquid butadiene is a copolymer composed of 40%
by weight or less of styrene and 60% by weight or more of 1,3-butadiene and has an average molecular weight of 300 to 5,000.

6. A composition according to Claim 3, wherein the modified product of liquid butadiene homopolymer is that obtained by modifying a low-molecular-weight butadiene homopolymer having an average molecular weight of 250 to 5,000 with 20% by weight or less of maleic anhydride.

7. A composition according to Claim 3, wherein the modified product of liquid butadiene homopolymer is that obtained by epoxidizing a low-molecular-weight butadiene homopolymer having an average molecular weight of 250 to 5,000 with an organic peracid and has an oxirane-oxygen content of 0.5 to 20% by weight.

8. A composition according to Claim 7, wherein the peracid is performic or peracetic acid.

9. A composition according to Claim 4, wherein the liquid polybutadiene resin is a liquid butadiene homopolymer and the content thereof is 3 to 27% by weight.

10. A composition according to Claim 5, wherein the liquid polybutadiene resin is a liquid butadiene copolymer and the content thereof is 3 to 27% by weight.

11. A composition according to Claim 6, wherein the liquid polybutadiene resin is a maleic-anhydride-modified liquid butadiene homopolymer and the content thereof is 2 to 12% by weight.

12. A composition according to Claim 7, wherein the liquid polybutadiene resin is an epoxidized liquid butadiene homopolymer and the content thereof is 2 to 10% by weight.

13. A composition according to Claim 1, which is incorporated with a plasticizer.