Note: Descriptions are shown in the official language in which they were submitted.
57~45 ~ .
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1 Thls lnvention relates -to a thermopl.a~tic .
resin compos:iti.on cxcellent in weather reslstance and
impact resist ~nce. More particularly, this invention
relates to a composition comprising a binary gra.ft-
copolymer of an ethylene-propylene rubber and an
aromatic vinyl compound or a ternary graft-copolymer
of these two components and a vinyl cyanide compound,
a mi.neral oil, and an antioxidant and/or an ul-tra-
: violet absorber. :
. 10 A development has heretofore been made of - .
.~ the process for producirg a graft-copolymer excellent
; in impact resistance as well as in weather resistance -.
` by graft-copolymerizing styrene or styrene and acrylo- .
.~ nitrile on an ethylene-propylene rubber, considering
15 that the ethylene-propylene rubber is excellent in .
weather resistance.
i : For preparing such impact resistant resins,
there have been known a bulk polymerization method - ~:
~ ~ (U.S. Patent 3,538,192), an emulsion polymerization .~:
.~ ~ 20 method (U.S. Patent 3,435,096), and, in addition, a
solution polymerization method (U.S. Patent 3,538,190
.~ and 3,538,191).
.~ Although the graft-copolymers obtained by .
~ such methods have a weather resistance comparable to ;~
.. : 25 - or even higher than that of, for example, ABS resins,
``, because &n ethy].ene-propylene rubber is used as the
~;~ rubber component, the graft-copolyrners have a defect ~ ;
that they are inferior in irnpact resistance particularly
~: at low temperatures to ABS resins. Further, when an
ethylene-propylene rubber i.s used, it has been necessary
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1 that the ~mount of the rubber be 10 - 15% larger than
that of thc diene rubber in ABS resins in order -to
obtain the same impact resis-tance at room temperature `~
as that of the ABS resins.
It is a known fact that various stabilizers
. ,. , , ~
have been added in order to prevent polymer materials ~ -
from degradation. However, even if various antioxldants
and ul-traviolet absorbers have been added for the
purpose of increasing the weather resistance, the
effect o:. such agents has only been recognizable in
an early stage of exposure to light, and it has been
considered to be difficult to sustain the effect for ~ ;~
a long period of time.
~` Further, as an example of addition of mineral ~`
: . . .
oil to rubber-reinforced plastic such as ABS resins
~ ~ there have been known Japanese Patent Publications
`~ No. Sho. 41-1551 (1966) and No. Sho. 41-16306 (]966).
However, the objects of these inventions are in replac-
ing a part of expensive rubber by inexpensive mineral
oil (Japanese Patent Publlcation No~ Sho. 41-1551) or
in improving impact strength at low temperature, ;~
~ hardness and processability by addition of mineral
`` oil (Japanese Patent Publication No. Sho. 41-16306).
As a result of examination iDy the inventors of the ;~
25 present invention, however, there has been kno~l that, ~ ~r
in said rubbe:.-reinforced plastics such as ABS resin
containing diene type Yubber, a mere addition of
mineral oil thereto does not make an improvement on
the weather resistance and also on the impact strength
at low -temperature.
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~ 7445
An object of this invention is to provide a thermoplastic resin
composition having excellent impact resistance particularly at low temper-
ature and weather resistance.
Another object of the invention is to provide a thermoplastic
resin composition comprising a graft-copolymer of an aromatic vinyl compound
and/or a vinyl cyanide compound on an ethylene-propylene rubber; mineral oil;
and an antioxidant and/or an ultraviolet absorber.
Other objects and advantages of this invention will be apparent
from the following description. -;
The inventors of this invention have done extensive research ~o
find that the impact resistance particularly at low temperature may be im-
proved and the weather resistance may become excellent by adding mineral oil
and an antioxidant and/or an ultraviolet absorber to a binary graft-copolymer
.. ..
of an ethylene-propylene rubber and an aromatic vinyl compound or a ternary
graft-copolymer of these two components and a vinyl cyanide compound. `
According to this invention, there is provided a thermoplastic
resin composition having excellent resistance to weather and impact, which
:. l ., ~ .
:l comprises~
~ ~A~ a graft-copolymer which is-
-- 20 ta) a binary graft-copolymer of ~1) a rubber component com- -:
prising at least 40% by weight of an ethylene-propylene
1 rubber selected from the group consisting of an e~hyl-
:. ene-propylene copolymer and ethylene-propylene terpoly-
mers and ~2) an aromatic vinyl compound, or
~b) a ternary graft-copolymer of ~1) a rubber component com-
prising at least 40% by weight of an ethylene-propylene
, rubber selected from the group consising of an ethylene-
propylene copolymer and ethylene-propylene terpolymers~
~2) an aromatic vinyl compound and ~3) a vinyl cyanide
. 30 compound;
~ ~5 c~ o~ h.~/o~
~L~ ~B) 0.5 to 10% by weight of mineral oi~1having a specific gravity
of 0.905 or more; and
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(C) an antioxidant, an ultraviolet absorber or both.
.~ The above thermoplastic resin composition can be prepared by
` adding to the binary or ternary graft-copolymer obtained by a conventional
method 0.5 - 10% by weight of mineral oil and an antioxidant and/or an
ultraviolet absorber. In producing the graft- ~ , the additives
in this invention may be added either before or after the polymerization,
` or during the course of polym0rization.
Contrary to the conventional way of securing approximately
` the same impact resistance as that of an ABS resin by increasing the
.~ ethylene-propylene rubber content of the graft-copolymer, this invention
'; lO enables a resin having impact resistance comparable to that of the ABS
resin to be obtained by simply adding 0.5 to 10%, preferably l to 5%,
by weight of mineral oil to the binary or ternary graft-copolymer. The
` effect of addition of an antioxidant and/or an ultraviolet absorber to -~
the graft-copolymer in this invention is amazingly enhanced in the pre-
sence of mineral oil. So far as the weather resistance is concerned,
the graft-copolymer in this invention is generally superior to the `i~
, ABS resin~ but the effect of addition of an antioxidant and/or an
ultraviolet absorber has been recognizable only in an early stage of
exposure to light, whereas the addition of mineral oil enables the
effect of said additives on the light exposure to be sustained for a
long period of time.
The mineral oil for use in this inv~ntion is
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a colourless or pàle yellow naphthene type hydrocarbon oil
having a specific gravity of 0.905 or more. ~-
The antioxidants for use in this invention are of phenolic
type, thioether type, amine type, phosphite type, and dithio acid -
salt type. The ultraviolet absorbers for use are of salicylic
acid type, benzophenone type, and benzotriazole type. These
: :
~ stabilizers may be used usually either alone or in combination of
, . ,
two or more and added usually in a proportion of 0.05 to 3% by -
weight based on the weight of the resin composition.
It is not desirable to add more than 10% by weight of mineral
oil to the graft-copolymer, because the mechanical properties are
markedly decreased and the balance of physical properties is damaged.
On th0 other hand, an addition of less than 0.5% by weight thereof
does not give a desirable effect.
The ethylene-propylene rubbers for use in this invention
~` include not only a binary copolymer consisting of ethylene and
propylene (hereinafter referred to as EPM)~ but also ethylene-
, propylene terpolymers (hereinafter referred to as EPDM) consisting
of said two components and a third component such as, for example,
., ~
' 20 dicyclopentadiene, ethylidenenorbornene,
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he~adiene, 1,5-hexadlene, 2-methyl-1,5-hexadiene,
l,~-cycloheptadiene, 1,5-cyclooct~diene, and mixtures
of these compounds.
The ethylene-propylene rubbers for use are
preferably those in which the molar ratio of ethylene
to propylene is in the range frorn 5 : 1 to l : 3.
. . . .
The propor-tion of unsaturated radicals in EPDM corres-
. . .
ponds preferably to an iodine number of 4 to 50. It ~-
is also possible to use at least two rubbers. As the ~
10 rubber component, there may be employed blends of 40 ~ ;
to 99.9% by weight of EPDM or ~PM with 60 to 0.1% by
weight of one or more members selected from,for example.
polybutadiene, polyisoprene, and styrenebutadiene rubbers.
Such blends of different types of rubbers are suitably
selected according to the intended use.
~ xamples of the aromatic vinyl compounds
to be used include, for example, one or more members
;~ ~ selected from styrene, a-methylstyrene, ~-chloro-
- styrene, dimethylstyrene and the like. Of these,
styrenè is preferred. ~ Acrylonitrile, methacrylo-
nitrile and the like may be used as the vinyl cyanide
.:~ : ,~
; compound.
The weight ratio of these vinyl compounds
~ to the rubber may be selected from a suitable range,
A~ 25 depending upon the intended use. Usually, 5 to 20
by weight of the rubber component is used with 95 to
. 80~o by weight of the aromatic vinyl compound for the ;~
binary graft-copolymer or the aromatic vinyl and vinyl
cyanide compounds for the ternary graft-copolymer.
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~ 74~5
1 However, in case a graft-copolymer is to be prepared
for the purpose of improving its compatibil:Lty with
other rubbers or resins, a weight ratio of the rubber
componen-t to the vinyl compounds as high as possible
is preferable because the degree of grafting is i.n-
creased. For i.nstance, a pre~erable range is from
: ~ 20 to 90~0 by weight of the rubber component based on ~ :~
. .;
:~ the weight of the vinyl compounds. :~ ~
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: . In the case of a ternary graft-copolymer
10 of the ethylene-propylene rubber with an aromatic . ,
.. vinyl compound and a vinyl cyanide compound, the
. weight ratio between both monomers is adjusted with-
. in the range from 4 : 3 to 5 : 1. For example, in .. i
. -the copolymerization system of styrene and acrylo-
, , . 15 ni-trile, the most suitable weight ratio ranges from .
65 : 35 to 80 : 20. ... `~
he graft-copolymer for use in this inven- :~:
tion can be prepared by bulk polymerlzation, emulsion .
; polymerization, and solution polymerization. Since
the ethylene-propylene rubber is i.nsoluble by nature
in a monomer mixture of styrene and acrylonitrile in :.
the above-mentioned ratio, and al.so a stable emulsi.on
of an ethylenc-propylene rubber cannot easily be
reproduced, the graft-copolymer obtained by bulk ~-
. 25 polymerization or emulsion polymerization tends to
. be inferior in impact resistance to that obtained by ;~
. . . ~ .
.. : solution polymerization. Although a graft-copolymer ~ :
: obta:ined by any polymerization method can be markedly
improved in impact strength particular]y at low tempe-
0 ratures, by the addition of mineral oi.l, the most
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~ 1 pronounced effect of the la.tter is exhibited in the
. . ,
; case of a gra:r-t-copolymer ob-tained by a solution poly-
. . merization method.
In preparing a gra.ft-copolyrner for use in:~
5 this invcntion by the solutlon polymerizat:ion method, .
. sui-table solvents are pentane, n-hexane, 3-methylpentane,
::: 2-methylpentane, 2,2- and 2,4-dimethylpentanes, heptane, .
.:: ~ ..
::~ cyclopentane, cyclohexane, and alkyl-substituted ;
cyclopentane and cyclohexane in which the alkyl has
: lO :l to ~ carbon atoms; also usable are aromatic hydro~ .~
` carbon solvents such as benzene, toluene, dimethyl- : :
. ~ ~
.~ benzenes, xylenes, ethylbenzene, diethylbenzenes, and
: triethylbenzenes.
On the other hand, solvents which may also ~ :
be used in combination wlth the above-listed aliphatic
or aromatic hydrocarbon solvents are ketones such as
` ~ acetone, methyl ethyl ketone, methyl-n-propyl ketone,
-.; diethyl ketone, 2~hexanone, 3-hexanonej acetophenone~
:: and propiophenone; esters such as:methyl formate,
~:~ 20 ethyl formate, methyl acetate, ethyl acetate, n~propyl : -
: i .
-:.z acetate, n~butyl acetate, n~amyl acetate, methyl .~
..
~ propionatej and methyl n~butyrate; ethers such as :~
.~ tetrahydrofurane and dioxane; halogen~substituted
~, .
aliphatic hydrocarbons such as dichloroethane and - ~
25 chloroform; and hydrocarbons containing hetero atoms ~ ~;
selected from nitrogen, oxygen and sulfur, such as
. ~ pyridine, aniline, acetonitrile, dimethylformamide,
dimethyl sulfoxide and the like.
~ The catalysts to be used in the grafting
:. 30 reaction are conventional radical polymerization
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79~45
1 catalysts. Suitable catalysts are, for example,
peroxldes such as benæoyl peroxide, lauroyl peroxide,
di-tert-butyl perioxide, acetyl peroxide, tert-butyl
peroxybenzoic acid, dicwnyl peroxide, peroxybenzoic
acid, peroxyacetic acid, tert-butyl peroxypivalate
and the like; and diazo compounds such as azobisisobutyro-
nitrile, and the like.
i ,
The catalyst may be used in an amount of ~`
O.1 to 10% by weight based on the weight of tha
10 vinyl monomer. The suitable polymerization tempera- ~
ture is 30C to 120~, particularly 50C to 80C. ~;
The polymerization time depends markedly on polymeri-
zation conditions, and is preferably adjusted so that
the conversion may reach 90~ or higher in 5 to 40
hours.
In this invention, the incorporation of an -
antioxidant, ultraviolet absorber, and mineral oil
can be effected by adding these additives to the
polymerization reaction mixture while being s-tirred
before, during, or after polymeriY~ation, or by blend-
`i; ing them with the isolated graft-copolymer immediately
:. :
before the latter is granulated in a granulator.
The invention is illustrated below in detail
with reference to Examples, but the invention is not
limited thereto.
~ !
- Example ~
,. :
Into a 10-liter separable flask provided
with a Dimroth cooler, a thermometer, a glass tube
for bubblir~g a gas, a Hopkins cooler, and a stirrer
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1~57445
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Wit}l three turbine-type blades were charged 324 g of EPDM having an iodine
number of 8.5, a Mooney viscosity of 61, and a propylene content of ~3% by
weight, and containing ethylidenenorbornene as the diene component, 3,600 g
of n-hexane, and 1,800 g of styrene. To the charged mixture, after having
been thoroughly dissolved, were added 600 g of acrylonitrile and 48 g of
benzoyl peroxide diluted with 2,400 g of ethylene chloride, and the resulting
mixture was allowed to polymerize at G7C. for 10 hours while being agitated
at 600 rpm under an argon atmosphere. After completion of the reaction, the
graft-polymerization solution was subjected to precipitation in 25 liters of
methanol. The precipitate was separated and dried under reduced pressure at
50C. for 20 hours, and then at 150C. for 3 hours to obtain a graft-copolymer
having a rubber content of 13.7% by weight.
To 100 parts by weight of ~he copolymer thus obtained were
added 3 parts by weight of mineral oil, namely Sonic Process Oil [a registered
trademark of Nippon Kogyo (Japan Mining) Co., Ltd., and manufactured by
'"~; the same], naphthene type R-1000, or aromatic types X-100, X-140 or X-200,
0.5 part by weight of a thioether-type antioxidant ~Sumilizer TPS, a
` registered trademark of Sumitomo Chemical Co. for distearyl thiodipropionate),
; 0.5 part by weight of a phenolic antioxidant (Irganox 1010, a registered
trademark of Ciba Geigy Co. for tetrakis (methylene 3-(3',5'-di-t-butyl-4'- ~ -
hydroxyphenyl)propionate)methane), and 0.5 part by weight of a benzophenone-
type ultraviolet absorber (Sumisorb 10, a registered trademark of
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~57~45
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1 Sumitomo Chemical Co. :~or 2-hydroxy-4-me~thoxybenzophe-
none). The mixture was pelletized by means of an
extruder and a pelletizer and molded by means of' an
in,jection molding machine to prepare JIS No. 3 dwnbbell
test pieces for tes-t:ing the tensile strength and test
pieces for testi.ng Izod impac-t strength specif'ied in
. ASTM D 256-56. Using these test pieces, the tensile
strength was tested at room temperature at a testing :
speed of 5 mm per minute, and the Izod impact strength
; 10 was tested in conformity with ASTM D 256-56. ~::
Referential Example ~ ~
' To a test of tensile strength and impact ' ,
':strength was subjected the resin composition obtained
in the same manner as in Example, except that the
`,15 mineral oil was not added to the graft-copolymer obtain~
ed in Example.
he test results obtained in Example and .
~`-Referential Example were as shown in Table 1.
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\ \ Physical. _ _ Notched Izod
\ property strength impact strength
\ ~ 2 (kg-cm/cm2)
\ Min.eral \ (kg/cm ) ._~ . .
Examplè oil \ 20a oa -30a
__ s p . r ~ _
: R - 1000 0. 9300 512 29.2 15.3 9.5
.~ . Example X - 100 1. 0037 532 21.2 14.6 9 - 3
x - 140 1.0065 53~ lg . o 15.0 9 - 5
~; X - 20G 1. 0154 52~ 23.0 14.2 ~ .1 ~ ~ ~
._ .... _ ... ,:
REXf ple 543 ¦ 17. 2 10.9 4.9 . .
-
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I The resin compositions obtained in Example
: ~ and Referential Example were compression-molded to
. prepare sheets, 3 mm in thickness. These sheets were
exposed to light for 100, 200, and 400 hours in Sunshine
5 Weather-0-meter wE-suN-Ha, manufactured by Toyo Rika
Co. Test pieces were cut from the exposed sheets and
~ tested for change in impact strength by means of a :
-~ Dynstat impact tester in conformity with BS 1330-1946 :
and DIN 53,453. The test results were as shown in
` 10 Table 2.
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. \ ~ 0 100 200 400
. \ Rxampl~ 1~ r~
. R - 1000 bneak bneak 43.3 32.1
Dynstat
strength Example X - 100 nbeak bneak 41.4 30.4 : ;
(kg-cm/cm2) X - 140 bnreak bneak 42-3 31-4
~ ¦ L l X - 200~ brea
`.`.~ Example _ break 51 4 21. a 16.4
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