DESCRIPTION
OLEFIN-BASED RESIN, METHOD FOR PRODUCING SAME AND PROPYLENE-BASED
RESIN COMPOSITION
5 TECHNICAL FIELD
[0001]
The present invention relates to an olefin resin and a method
for producing the same, a propylene resin composition including
the olefin resin, and a molded article made of the propylene resin
10 composition. More specifically, the present invention relates
to a propylene resin composition capable of producing a molded
article having an excellent balance betweeri rigidity and impact
resistance, and an olefin resin capable of producing the propylene
resin composition.
15 BACKGROUND ART
[0002].
Propylene resins, among olefin resins, are used in a variety
of fields, such as daily goods, kitchen utensils, packaging films,
consumer electronics, mechanical parts, electric components, and
20 automobile parts, and propylene resin compositions including
various types of additives are used, depending on required
performances. In recent years, efforts for producing light
weight, thin-walled molded articles have been made in various
industrial fields, as an attempt to realize 3R (Reduce, Reuse,
I.
I
·
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and Recycle) in order to achieve a recycling-oriented society.
At the same time, improvements in the propylene resin compositions
have been made, so that sufficient rigidity and impact resistance
can be obtained even in the light weight, thin-walled molded
5 articles.
[0003]
As a polypropylene having an improved impact resistance,
a polyprOpylene block copolymer has been produced industrially,
and widely used in the above mentioned applications. This block
10 copolymer is also referred to as an impact copolymer, or a
heterophasic copolymer. Specifically, in a multistage
polymerization process for producing the block copolymer, the
polymerization of a homopolymer is carried out first, and then
ethylene is copolymerized in a subsequent reaction tank, to
15 produce a composition includirig'an ethylene-propylene polymer.
Since the thus produced block copolymer has a structure
{sea-island structure) in' which "islands" of the
ethylene-propylene polymer float in the "sea" of the homopolymer,
it has a better impact strength as compared to the propylene
20 homo polymer. Note, however, that the term "block" in the
"polypropylene block copolymer" does not mean it is a "block
copolymer". In other words, the polypropylene block copolymer
is not composed of a homo-polypropylene chain and an
ethylene-propylene copolymer chain, chemically bound to each
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other, but is a composition obtained by a two-stage
polymerization.
[0004]
For example, Patent Document 1 discloses a propylene resin
5 composition composed of: a metallocene catalyst-based propylene
block copolymer composition, in which the rubber moiety of the
ethylene-propylene copolymer is constituted by two components
having a low ethylene content and a high ethylene content; an
elastomeri and an inorganic filler. Further, Patent Document 2
10 discloses a propylene block copolymer-based resin composition
containing a high molecular weight propylene/ethylene copolymer
rubber. Although the propylene resin composition disclosed in
Patent Document 1 or Patent Document 2 has an improved impact
resistance, the improvement to meet a demand for further rigidity
15 has been insufficient.
[0005]
In contrast, Patent Document 3 discloses a technique to
carry out a multistage polymerization using_ a catalyst containing
a bridged bisindenyl zirconocene capable of producing a
20 polypropylene having a vinyl group at its terminal. In the
technique disclosed in Patent Document 3, propylene is polymerized
in the first stage, and the polypropylene is copolymerized with
a small amount of comonomer(s) in the latter stage, so that a
portion of the polypropylene having a vinyl structure at its
i' ····--- ------
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terminal, produced in the first stage, is introduced into the main
chain in the latter stage polymerization. As a result, a
composition including a branched propylene copolymer composed of
a grafted polypropylene can be obtained. Further, Patent
5 Document 4 and Patent Document 5 disclose techniques to obtain
a branched polymer in which the molecular weight of the side chain
polypropylene is increased, by using a catalyst system carrying
a bridged bisindenyl hafnocene complex. Not like the above
mentioned block copolymer, the polymer produced by any of the
10 techniques disclosed in Patent Documents 3 to 5 partially includes
a branched polymer. The presence of the branched polymer improves
the compatibility between the polypropylene moiety and the rubber
moiety, and thus a polypropylene composition characterized by
having excellent transparency and a high fusibility can be
15 obtained. However, in the polymer produced by any of the
techniques disclosed in Patent Documents 3 to 5, the melting point
of the polypropylene moiety is not sufficiently high as compared
to the above mentioned polypropylene block copolymer obtained
using a general purpose Ziegler-Natta catalyst system, and there
20 are limitations on the comonomer compositions of the rubber moiety
and on the molecular weight. Therefore, obtaining a
polypropylene resin composition which sufficiently satisfies
both the rigidity and impact resistance has not yet been
successful.
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[0006]
In view of the above, techniques have been developed to
produce a block polymer (including a straight chain or a branched
polymer), in which an ethylene copolymer is bound with
5 polypropylene, and which has an excellent capability to modify
a polypropylene resin.
[0007]
Patent Document 6 and Patent Document 7 disclose methods
in which a reactive functional group such as maleic acid, a halogen,
10 or a leaving metal is introduced into a polyolefin, and then a
I
I
j
1l
:1
coupling reaction of an ethylene/a-olefin copolymer chain with
a crystalline propylene polymer chain is allowed to proceed, to
produce a composition having a high target polymer content.
I
,",
I However, in the methods disclosed therein, there is a potential
15 risk that problems in terms of product quality could occur, such
as: poor productivity due to complex reaction processes including
a step of introducing the functional group into the polymer and
a coupling step; coloration or foul odor due to byproducts or
residual substrates produced during respective reaction steps;
20 and contamination due to eluted components.
[0008]
Patent Document 8 discloses a method for producing a
straight-chain block copolymer composed of an ethylene/a-olefin
copolymer chain and a crystalline polypropylene chain, using a
l " - -- ·--'--~--' ---------------
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reversible chain transfer technique. However, since this method
requires a reversible chain transfer agent, it has a poor economic
efficiency and its application is thereby limited. On the other
hand, methods have also been disclosed in which a branched
5 copolymer of an ethylene copolymer and polypropylene is obtained
in a cost-efficient manner, utilizing a polymerization catalyst
technique. For example, Patent Document 9 and Patent Document
10 describe that a branched olefin polymer composition including
a main chain soft segment constituted by an ethylene copolymer
10 and a side chain hard segment constituted by polypropylene is
useful as a polypropylene resin modifier. Patent Document 9
discloses a composition including a grafted olefin polymer having
)j side chains composed of an ethylene polymer. Patent Document 10
discloses a composition including a grafted olefin polymer,
15 obtained by using a specific polymerization catalyst,
characterized by having excellent physical ·p-roperties as a
thermoplastic elastomer, such as elastic recovery, and having side
chains composed of a crystalline propylene polymer.
[0009]
20 However, although the composition disclosed in Patent
Document 9 or Patent Document 10 includes a branched olefin polymer
having side chains composed of a crystalline propylene polymer,
it has been found that the disclosed technique has a low efficiency
in producing the grafted olefin polymer, and, when the polymer
L.C __ ,' __ :_, '_- ___ ,_',•,-,,_,,_:__,_'-.:'--"•-----·-'--'"
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is blended with a polypropylene resin to form a mixed composition,
the improvement in the balance between the physical properties
is insufficient. In order to obtain a branched copolymer having
a high content of polypropylene side chains and an excellent
5 modification ability, a catalyst having a good copolymerizability
is required, which is capable of efficiently copolymerizing a
vinyl terminated polypropylene macromonomer produced in the first
stage Polyffierization and increasing its molecular weight in the
latter stage polymerization vessel, at a high temperature (90°C
10 or more) at which the macromonorner is able to melt in a favorable
manner.
PRIOR ART DOCUMENTS
PATENT DOCUMENTS
[0010]
!
15 Patent Document 1: JP 2007-211189 A
' r Patent Document 2 : JP 2003-327758 A
I'
~ Patent Document 3: JP 2001-525460 A
r:
't~ Patent Document 4 : JP 2008-144152 A
i':
f
t) Patent Document 5: JP 2009-114404 A
t;
(-
·' 20 Patent Document 6: JP 2009-102598 A i'
:':
i! "·' Patent Document 7 : JP 2009-227898 A
! Patent Document 8 : JP 2013-529705 A
i
Patent Document 9: JP 2001-527589 A
Patent Document 10: wo 2013/061974 A
I;
",.
1' i;
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SUMMARY OF THE INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION
[0011]
An object of the present invention is to provide an olefin
5 resin having a low content of byproducts or residual substrates
which causes quality problems, and a high content of a polymer
composed of an ethylene/ex-olefin copolymer chain and a crystalline
propylene polymer chain, chemically bound to each Other, wherein
a propylene resin composition obtained from the olefin resin and
10 polypropylene has an excellent balance between rigidity and impact
resistance; and to provide a method for producing the olefin resin,
and the propylene resin composition.
MEANS FOR SOLVING THE PROBLEMS
[0012]
15 The present inventors haVe found out, as a result of
intensive stUdie:'l, that the: .'~.bove mentioned problems can be solved
by: an olefin resin including a grafted olefin polymer having a
main chain composed of an ethylene/a-olefin copolymer and a side
chain (s) composed of a propylene polymer, and satisfying specific
t-·. 20 requirements; a specific method for producing the olefin resin;
i,
t; and a propylene resin composition including the olefin resin.
'
[0013]
In other words, the present invention relates to the
following [1] to [12].
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[1] An olefin resin (~) satisfying the following requirements
(I) to (VI):
(I) the olefin resin (~) comprises a grafted olefin polymer
[Rl] comprising a main chain composed of an ethylene/a-olefin
5 copolymer and a side chain composed of a propylene polymer;
(II) when the ratio of the amount of the propylene polymer
contained in the olefin resin {~) is taken as P wt%, the value
P is within the range of from 5 to 60;
(III) when the ratio of the amount of a component (s) having
10 a peak temperature of a differential elution curve as measured
by cross-fractionation chromatography (CFC) using
a-dichlorobenzene as a solvent of less than 65°C, to the amount
of the olefin resin (~) is taken as E wt%, the value a represented
by the following equation (Eq-1) is 1.4 or more;
15 [0014]
a= (100-E) /P (E q -1)
(IV) the melting point (Tm) and the glass_ transition
temperature (Tg)' as measured by differential scanning
calorimetry {DSC), are within the range of from 120 to 165°C and
20 within the range of from -80 to -30°C, respectively;
(V) the hot xylene-insoluble content is less than 3 wt%;
and
(VI) the limiting viscosity [~] as measured in decalin at
135°C is within the range of from 0.5 to 5.0 dl/g.
<-
~-..
~:·
- ., :. -- ___ ;
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[2] The olefin resin (~) according to the item [1], wherein the
ratio of repeating units derived from ethylene with respect to
the total repeating units is within the range of from 20 to 80
mol%.
5 [3] The olefin resin (~) according to the item [1] or [2],
wherein the propylene polymer constituting the side chain(s) of
the grafted olefin polymer [Rl] has an isotactic pentad fraction
(mmmm) of 93% or more.
[4] The olefin resin (~) according to any one of the items [1]
10 to [3], wherein the propylene polymer constituting the side
chain(s) of the grafted olefin polymer [R1] has a weight average
molecular weight within the range of from 5,000 to 100,000.
[5] The olefin resin (~) according to any one of the items [1]
to [4], wherein the ethylene/o-olefin copolymer constituting the
15 main chain of the grafted olefii-l polymer [Rl] has a weight average
molecular weight within the range of from 50,000 to 200,0.00.
[ 6] The olefin resin {~) according to any one of the items [1]
to [5], wherein the olefin resin (~) has a phase-separated
structure composed of a sea phase constituted by a non-crystalline
20 component and an island phase constituted by a crystalline
component, and wherein the particles of the island phase have an
average diameter as observed in a transmission electron microscope
image within the range of from 50 nm to 500 nm.
[7] A method for producing the olefin resin {~) according to
'_, ----- _ _-: __ ,:_,------ _, -_ ---' ---- -~- ,_- ; -
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any one of the items [1] to [ 6], the method comprising the following
steps (A) and (B):
(A) polymerizing propylene in the presence of an olefin
polymerization catalyst comprising a transition metal compound
5 [A] of a transition metal of Group 4 in the periodic table, the
compound comprising a ligand having a dimethylsilylbisindenyl
skeleton, to produce a polypropylene having terminal
unsaturation; and
(B) copolymerizing the polypropylene having terminal
10 unsaturation produced in the step (A), ethylene, and at least one
a-olefin selected from c:x-olefins having from 3 to 20 carbon atoms,
in the presence of an olefin polymerization catalyst comprising
a bridged metallocene compound represented by the following
general formula [B]:
15 [0015]
[B]
(wherein in the formula [B],
R1
, R2
, R3
, R4
, R5
, R8
, R9 and R12 each independently represents
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12
a hydrogen atom, a hydrocarbon group, a silicon-containing group,
or a hetero atom-containing group other than silicon-containing
groups, and two mutually adjacent groups of the groups represented
by R1 to R4 are optionally bound together to form a ring;
5 [0016]
R6 and R11 are the same atom or the same group selected from
hydrogen atom, hydrocarbon groups, silicon-containing groups,
and hetero atom-containing groups other than the
silicon-containing groups; R7 and R10 are the same atom or the same
10 group selected from hydrogen atom, hydrocarbon groups r
silicon-containing groups, and hetero atom-containing groups
other than the silicon-containing groups; R6 and R7 are optionally
bound together: to form a ring; and R10 and R11 are optionally bound
together to form a ring; with the proviso that all of R6
, R7
, R10
15 and R11 are not hydrogen atoms;
[0017]
R13 and R14 each independently represents an aryl groupi
M1 represents a zirconium atom or a hafnium atom;
Y1 represents a carbon atom or a silicon atom;
20 [0018]
Q represents a halogen atom, a hydrocarbon group, a
halogenated hydrocarbon group, a neutral conjugated or
non-conjugated diene having from 4 to 10 carbon atoms, an anionic
ligand, or a neutral ligand capable of being coordinated with a
' ''
SF-2911
13
lone pair of electrons;
j represents an integer of from 1 to 4; and
in cases where j is an integer of two or more, a plurality
of Qs may be the same as or different from each other) .
5 [ 8] The method for producing the olefin resin (~), according
to the item [7], wherein the step (B) is a solution polymerization
process carried out at a polymerization temperature of 90°C or
more.
[9] A propylene resin composition comprising a propylene resin
10 (a) and the olefin resin {[)} according to any one of the items
[1] to [6].
[10] The propylene resin composition according to the item [9],
comprising 50 to 98 parts by weight of the propylene resin (a)
and 2 to 50 parts by weight of the olefin resin ([)) (wherein the
15 total amount of the propylene -re-sin {a) and olefin resin (~) is
100 parts by weight}.
[11] The propylene resin composition according to the item [9]
or [10], wherein the olefin resin (~) is obtained by the method
for producing the olefin resin (~), according to the item [7] or
20 [8].
[12] A molded article obtainable from the propylene resin
composition according to any one of the items [9] to [11].
EFFECT OF THE INVENTION
[0019]
----- ------------------------
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14
Since the olefin resin according to the present invention
has a low content of byproducts or residual substrates which causes
quality problems, and a high content of a graft polymer, it has
a markedly high compatibility with a polypropylene resin and
5 significantly improved mechanical properties as compared to the
existing olefin elastomers, styrene elastomers, and the like.
[0020]
Further, since it is possible to continuously produce the
olefin resin according to the present invention, by using a
10 specific catalyst, preferably one used in a high-temperature
solution polymerization system, a resin having a desired structure
can be produced economically.
[0021]
Still further, since the propylene resin composition
15 according to the present invention has a high rigidity, high impact
resis_t_an_ce, _and an excellent balance_ between the rigidi t_y and the
high impact resistance, it can be suitably used in various types
of products, such as automobile parts, food containers, and
medical containers.
ii 20 BRIEF DESCRIPTION OF TE DRAWINGS
1:
[0022]
FIG. 1 is a transmission electron microscope image of the
olefin resin (~-2) obtained in Example 2.
FIG. 2 is a transmission electron microscope image of the
,. __ ,_ ------
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15
olefin resin (B-1) obtained in Comparative Example 3.
FIG. 3 is a transmission electron microscope image of the
propylene resin composition obtained in Example 13.
FIG. 4 is a graph illustrating the correlation between the
5 ratio P, the ratio E, and the value a.
FIG. 5 is a graph plotted with the ratio P against the ratio
E of each of the Examples and Comparative Examples, and shown with
a line representing the correl-ation betWeen the ratio P and the
ratio E when a = 1.4.
10 MODE FOR CARRYING OUT THE INVENTION
[0023]
The olefin resin [~], the method for producing the olefin
resin, the propylene resin composition, and the molded article,
according to the present invention, will now be described in
15 detail.
' L

,r.~
I
The olefin resin [~] according to the present invention may
t'
['
~ be composed of one type of olefin polymer_alone, or two or more
['i
!! types of olefin polymers, but it is characterized in that the
fi
[,. 20 olefin resin [j3] necessarily satisfies all of the following
i' ~ requirements (I) to (VI) :
(I) the olefin resin (~) includes a grafted olefin polymer
[Rl] containing a main chain composed of an ethylene/a-olefin
copolymer and a side chain composed of a propylene polymer;
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16
(II) when the ratio of the amount of the propylene polymer
contained in the olefin resin (~) is taken as p wt%, the value
P is within the range of from 5 to 60;
(III) when the ratio of the amount of a component (s) having
5 a peak temperature of a differential elution curve as measured
by cross-fractionation chromatography (CFC) using
a-dichlorobenzene as a solvent of less than 65°C, to the amount
of the olefin resin (~) is taken as E wt%, the value a represented
by the following equation (Eq-1), in relation to the ratio E and
10 the ratio P, is 1. 4 or more;
[0024]
a= (1 0 0-E) /P (E q -1)
(IV) the melting point (Tm) and the glass transition
temperature (Tg I , as measured by differential scanning
15 calorimetry (DSC), are within the range of from 120 to 165°C and
within .. the .. range of from -80 to -30°C, respectively;
(V) the hot xylene-insoluble content is less than 3 wt%;
and
(VI) the limiting viscosity [~] as measured in decalin at
20 135°C is within the range of from 0.5 to 5.0 dl/g.
,,,
'
[0025]
:.
These requirements (I) to {VI) will now be described
specifically.
[Requirement (I)]
, ... _ -- - - ----- ----- ' --
SF-2911
17
The olefin resin (~) includes the grafted olefin polymer
[Rl] as an essential component. The grafted olefin polymer [Rl]
is a graft copolymer containing a main chain composed of an
ethylene/a-olefin copolymer and a side chain composed of a
5 propylene polymer·.
[0026]
In the present invention, the term "graft copolymer" refers
to a polymer in which one or more side chains are bound to a main
chain.
10 [0027]
Since the grafted olefin polymer [Rl] has a structure in
which side chains composed of a propylene polymer are chemically
bound to a main chain composed of a non-crystalline or
low-crystalline ethylene/a-olefin copolymer, the olefin resin
15 (~) including the grafted ole-fi'n polymer [Rl] exhibits a high
compatibility as compared to an ethylene/a-olefin copolymer
propylene resin having a straight chain structure. Therefore,
the propylene resin composition including the olefin resin (~)
and a propylene resin (a) to be described later is capable of
20 exhibiting a markedly superior balance between physical
properties.
[0028]
Further, since the olefin resin (~) includes the grafted
olefin polymer [Rl] having the above mentioned structure, it is
- - ---- - __ , --- -- ---· '"'"'·-
SF-2911
18
characterized by having a reduced stickiness, and an excellent
handleability when formed into pellet products, as compared to
common ethylene elastomers (such as ethylene/propylene copolymer,
ethylene/butene copolymer and ethylene/octene copolymer) .
5 [0029]
The grafted olefin polymer [Rl] is a graft copolymer having
a main chain and one or more side chains, as described above. In
the present invention, the main chain and the side chains of the
grafted olefin polymer [Rl} preferably satisfy the following
10 requirements (i) to (iv):
(i) the main chain is composed of repeating units derived
from ethylene and repeating units derived from at least one
a-olefin selected from a-olefins having from 3 to 20 carbon atoms,
wherein the ratio of the repeating units derived from the a-olefin
15 with respect to the total repeat'ing units contained in the main
chain is within the range of from 10 to 50 mol%;
(ii) the main chain is derived from an ethylene/a-olefin
copolymer having a weight average molecular weight of from 10,000
to 200,000;
20 (iii) the side chains are composed of repeating units
substantially derived from propylene; and
{iv) the side chains are derived from a propylene polymer
having a weight average molecular weight of from 5, 000 to 100,000.
[0030]
- -----------~-~-'" -- _,,,.,- -.. ,._ ,;,._:·"--'
SF-2911
19
These requirements (i} to (iv) will now be described
specifically.
[Requirement (i) ]
The main chain of the grafted olefin polymer [R1] is composed
5 of an ethylene/cx:--'olefin copolymer, and it serves as a moiety
responsible for providing properties such as flexibility and low
temperature properties required for a modifier, in the grafted
olefin polymer [Rl]. In order to secure such properties, the main
chain of the grafted olefin polymer [R1] is composed of repeating
10 units derived from ethylene and repeating units derived from at
least one a-olefin selected from a-olefins having from 3 to 20
carbon atoms.
[0031)
Specific examples of the o:-olefin having from 3 to 20 carbon
15 atoms, copolymerized with ethy'lene in the ethylene/a-olefin
:_: copolymer, include propylene, 1-butene, 2-methyl-1-propene,
II,, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene,
;,
't:
0 ''
2-ethyl-1-butene, 2, 3-dimethyl-1-butene,_ 2-methyl-1-pentene,
I
(,'
r~
3-methyl-1-pentene, 4-methyl-1-pentene, 3,3-dimethyl-1-butene,
·:·
~;
' 20 r 1-heptene, methyl-1-hexene, dimethyl-1-pentene, ethyl-1-pentene,
(, e:
' trimethyl-1-butene, methylethyl-1-butene, 1-octene,
methyl-1-pentene, ethyl-1-hexene, dimethyl-1-hexene,
propyl-1-heptene, methylethyl-1-heptene, trimethyl-1-pentene,
\ propyl-1-pentene, diethyl-1-butene1 1-nonene, 1-decene,
SF-2911
20
1-undecene, 1-dodecene, and the like.
[0032]
More preferred is an a-olefin having from 3 to 10 carbon
atoms, and still more preferred is an a-olefin having from 3 to
5 8 carbon atoms. Specific examples thereof include: linear
olefins such as propylene, 1-butene, 1-pentene, 1-hexene,
1-octene, and 1-decene; and branched olefins such as
4-methyl-1-pentene, 3-methyl-1-pentene, and 3-methyl-1-blit·e~e.· ·
Among these, preferred is propylene, 1-butene, 1-pentene,
10 1-hexene, or 1-octene, and still more preferred is !-butene,
1-pentene, 1-hexene, or 1-octene. When 1-butene, 1-pentene,
1-hexene, or 1-octene is used as the a-olefin having from 3 to
20 carbon atoms to be copolymerized with ethylene, a propylene
resin composition having the best physical property balance
{ 15 between the rigidity and the imp'act resistance can be obtained.
':<
20
[0033]
The ratio of the repeating units derived from ethylene with
respect to the total repeating units contained in the main chain
of the grafted olefin polymer [Rl] is within the range of from
50 to 90 mol%, and preferably from 60 to 90 mol%. Further, the
ratio of the repeating units derived from the a-olefin with respect
to the total repeating units contained in the main chain is within
the range of from 10 to 50 mol%, and preferably from 10 to 40 mol%.
[0034]
' '
SF-2911
21
The relationship between the ratio of repeating units
derived from ethylene and the repeating units derived from the
a-olefin with the glass transition temperature (Tg} varies
depending on the type of the ex-olefin used. However, it is
5 preferred that the ratio of the repeating units derived from
ethylene and the repeating units derived from the a-olefin
contained in the main chain of the grafted olefin polymer [Rl]
be within the aboVe mentioned range, in order to achieve the glasS
transition temperature (Tg) within the range described in the
10 requirement (IV) .
[0035]
When the ratio of the repeating units derived from ethylene
and the repeating units derived from the a-olefin contained in
the main chain is within the above mentioned range, the resulting
15 olefin resin {!)) will have an -excellent flexibility and low
temperature properties, and thus the propylene. resin composition
containing the olefin resin (~) will have an excellent impact
resistance at low temperature. On the other hand, when the ratio
of the repeating units derived from the a-olefin is less than 10
20 mol%, the resulting olefin resin will have a poor flexibility and
low temperature properties, and thus the propylene resin
composition containing the resin may have a poor impact resistance
at low temperature.
[0036]
' - - ' :,- -'-'---'--'- -- - ' ______ , ,__ -'-----'' -
SF-2911
22
The molar ratio of the repeating units derived from ethylene
and the repeating units derived from the a-olefin contained in
the main chain can be adjusted by controlling the ratio of the
concentrations of ethylene and the a-olefin to be present in the
5 polymerization reac:tion system in the step of producing the main
chain.
[0037]
The molar ·ratio. (~oi%) · ~f the repeating units derived from
the a-olefin contained in the main chain, namely, the a-olefin
10 composition in the main chain, can be obtained, for example, by
obtaining, in a conventional manner, the a-olefin composition in
an ethylene/a-olefin copolymer obtained under conditions where
a polypropylene having terminal unsaturation to be described later
is not contained; or by deducting the influence of the
r 15 polypropylene having terminal uns'aturation or the side chains from
the a-olefin composition of the olefin resin (~) .
[Requirement (ii)]
The weight average molecular weight of the
ethylene/a-olefin copolymer constituting the main chain of the
20 grafted olefin polymer [Rl] is within the range of from 50,000
to 200,000. The weight average molecular weight of the
ethylene/a-olefin copolymer is preferably within the range of from
100,000 to 200,000, in order to improve the moldability (fluidity)
of the resin while maintaining the mechanical strength in the
,,
L-;
[ .. .:.. ,- ,.,._._, __ ; __ ,_,_ ~- --- '
SF-2911
23
polypropylene resin composition according to the present
invention. The weight average molecular weight as described
above is a weight average molecular weight in terms of polyethylene,
as obtained by gel permeation chromatography (GPC) .
5 [0038]
When the weight average molecular weight of the
ethylene/a-olefin copolymer constituting the main chain of the
grafted olefin polymer [Rl] is within the above mentioned range,
the propylene resin composition containing the olefin resin (~)
10 tends to have a better balance between the impact resistance,
rigidity and toughness. On the other hand, a weight average
molecular weight of less than 501 000 results in a decreased impact
resistance or toughness 1 while a weight average molecular weight
of greater than 200, 000 causes a poor dispersion in the propylene
15 resin, possibly failing to obt'ain a desired balance between
physical properties.
[0039]
The weight average molecular weight of the
ethylene/a-olefin copolyme_r constituting the main chain of the
20 grafted olefin polymer [Rl] can be adjusted by controlling the
ethylene concentration in the polymerization system in a
production step to be described later. The concentration of
ethylene can be controlled, for example, by adjusting the partial
pressure of ethylene or adjusting the polymerization temperature.
SF-2911
24
The adjustment of the weight average molecular weight of the
ethylene/a-olefin copolymer constituting the main chain can also
be achieved by supplying hydrogen into the polymerization system.
[0040]
5 The weight average molecular weight of the
ethylene/a-olefin copolymer constituting the main chain can be
obtained, for example, by analyzing the ethylene/a-olefin
copolymer produced under conditions where the polypropylene
having terminal unsaturation to be described later is not
10 contained; or by analyzing the olefin resin (13) and deducting the
influence of the polypropylene having terminal unsaturation or
the side chains from the analyzed result.
[Requirement (iii}]
The side chains of the grafted olefin polymer [Rl] are
15 composed substantially of repeating units derived from propylene.
The side chains of the grafted olefin polymer [Rl] are a propylene
polymer composed substantially of repeating units derived from
propylene and having an isotactic regularity.
[0041]
20 The propylene polymer composed substantially of repeating
units derived from propylene refers to a polymer in which the molar
ratio of the repeating units derived from propylene with respect
to the total repeating units contained in the propylene polymer
is preferably from 99.5 to 100 mol%. In other words 1 a small amount
~ I i I
"",,
<
SF-2911
25
of ethylene and an a-olefin (s) other than propylene may be
copolymerized in the propylene polymer, to the extent that the
functions and characteristics thereof are not impaired.
[0042]
5 More preferably, the side chains of the grafted olefin
polymer [Rl] are a propylene polymer chain having an isotactic
pentad fraction (mmmm) of 93% or more.
[0043]
When the side chains of the grafted olefin polymer [Rl] have
10 the above mentioned characteristics, the side chains exhibit
crystallinity and have a melting point. When the side chains of
the grafted olefin polymer [Rl] are an isotactic polypropylene
polymer having a high melting point, they serve to increase the
compatibility of the olefin resin (~) with the propylene resin.
15 Therefore, the resulting propylene resin composition maintains
a good rigidity and hardness, while exhibiting a good impact
resistance.
[0044]
The grafted olefin polymer [Rl] can be obtained by
20 copolymerizing the polypropylene having terminal unsaturation
produced in step (A), ethylene, and the a-olefin, in the production
step (B) of the olefin resin {~) to be described later. In other
words 1 the composition and the stereoregularity of the
polypropylene having terminal unsaturation correspond to the
;
I
'I
SF-2911
26
composition and the stereoregularity of the side chains of the
grafted olefin polymer [Rl]. Therefore, the composition and the
stereoregularity of the polypropylene having terminal
unsaturation to be produced in the step {A), calculated by a known
5 method, can be defined as the composition and the stereoregulari ty
of the side chains of the grafted olefin polymer [Rl].
[Requirement (iv)]
The side chains are derived from a propylene polymer having
a weight average molecular weight of from 5,000 to 100,000. In
10 other words, the grafted olefin polymer [Rl] has a structure in
which chains of a macromonomer which is a propylene polymer having
a weight average molecular weight of from 5,000 to 100,000 are
bound to the ethylene/a-olefin copolymer, and the propylene
polymer moiety of the grafted olefin polymer constitutes the side
15 chains. The weight average molecular weight is preferably within
the range of from 5, 000 to 60,000, and more preferably, from 5, 000
to 25,000.
[0045]
When the weight average molecular weight of the propylene
20 polymer constituting the side chains of the grafted olefin polymer
[Rl) is within the above mentioned range, the compatibility of
the propylene polymer with the olefin resin (~) is increased, and
the propylene resin composition containing the propylene resin
and the olefin resin (~) will have a good impact resistance and
SF-2911
27
elongation at break, as well as a good fluidity during injection
molding.
I 004 6 I
When the weight average molecular weight of the propylene
5 polymer constituting the side chains of the grafted olefin polymer
[Rl] is less than S, 000, the interface strength with the propylene
resin is decreased, possibly resulting in a decrease in the
elongation or the impact resistanc~·- ~f the propylene ·resiri
composition.
10 [0047]
When the weight average molecular weight of the propylene
polymer constituting the side chains of the grafted olefin polymer
[Rl] is greater than 100,000, the fluidity during molding of the
resin composition containing the olefin resin (~) is impaired,
i: 15 possibly causing a deterioration-in workability. Further, there
are cases where the compatibility between the p:r:·opylene resin and
the olefin resin (~) is reduced tb result in a decrease in the
tensile elongation or the impact resistance of the propylene resin
composition containing the propylene resin and the olefin resin
20 (~), or in a decrease in the surface hardness of a molded article
obtained from the propylene resin composition.
[0048]
The weight average molecular weight of the propylene polymer
constituting the side chains can be obtained by measuring the
SF-2 911
28
weight average molecular weight of the polypropylene having
terminal unsaturation produced in the step (A) by a conventional
method, in the same manner as described in the "Requirement {iii)"
above. For example, the weight average molecular weight in terms
5 of polypropylene of the polypropylene having terminal
unsaturation as measured by gel permeation chromatography (GPC}
can be used as the weight average molecular weight of the propylene
polymer constituting the side chains.
[0049]
10 The weight average molecular weight of the propylene polymer
constituting the side chains can be adjusted by controlling the
polymerization temperature or the polymerization pressure in the
production step (A) to be described later.
[Requirement (II)]
15 When the ratio of the amount of the propylene polymer
contained in the olefin resin ( ~) (hereinafter; also referred to
as the ratio P) is taken as P wt%, the value Pis within the range
of from 5 to 60%. As used herein, the amount of the propylene
;,
polymer contained in the olefin resin ( ~) refers to the total sum
20 of the amount of the polypropylene side chains incorporated into
the main chain in the polymerization step {B) to be described later,
and the amount of a straight-chain polypropylene polymer
unincorporated into the main chain.
[0050]
SF-2911
29
The ratio P is preferably from 8 to 50 wt%, and more
preferably, from 8 to 40 wt%.
[0051)
When the ratio Pis within the above range, the compatibility
5 of the propylene polymer with the olefin resin ([3) is increased,
and the propylene resin composition containing the propylene
polymer and the olefin resin(~} will have a good impact resistance
and elongation at break. When the ratio P is less than 5, the
compatibility with the propylene polymer is reduced, and the
10 resulting propylene resin composition may not have a good impact
resistance or elongation at break. When the ratio P is greater
than 60, the relative content of the ethylene/a-olefin copolymer
is reduced, and the resulting propylene resin composition may not
have a good impact resistance at low temperature or elongation
15 at break.
[0052]
The ratio P can be obtained, for example, from the ratio
of the weight of the polypropylene having _terminal unsaturation
used in the polymerization step (B) to be described later, to the
20 weight of the resulting olefin resin (~).
[0053)
The polypropylene having terminal unsaturation refers to
a polypropylene having unsaturated terminals represented by the
following terminal structures (I) to (IV). The term "poly" in
:-::
~:_,
i-
' -' ··-----~-"-- ,.,.~ ----- ------- ·--
SF-2911
30
each of the terminal structures (I) to (IV) indicates the binding
position of the terminal structure and a propylene polymer
molecular chain other than the terminal structures.
[0054]
5 Terminal structure (D
Poly
Terminal structure (II)
Poly
Terminal structure (III)
10 Poly
Terminal structure (IV)
Poly
The ratio of the number of the unsaturated terminals
contained in the polypropylene having terminal unsaturation is
15 usually from 0.1 to 10 per 1,000 carbon atoms, and more preferably
0.4 to 5.0. Further, the ratio of the number of the unsaturated
terminal represented by the terminal structure (I), generally
referred to as a terminal vinyl, is usually from 0.1 to 2.0, and
SF-2911
31
preferably from 0.4 to 2.0 per 1,000 carbon atoms.
[0055]
The quantification of the unsaturated terminals can be
performed by determining the terminal structures of the
5 polypropylene having terminal unsaturation by 1H-NMR measurement.
The 1H-NMR measurement can be performed according to a
conventional method. The assignment of the terminal structures
can be performed according to the method described in
Macromolecular Rapid Communications 2000, 1103, or the like.
10 [0056]
In the case of the terminal structure (I), for example, when
the integral value of 5 4.9 to 5.1 {2H} is taken as A, and the
total integral value derived from the propylene polymer is taken
as B, the ratio of the number of the terminal structure {I} per
15 1, 000 carbon atoms can be obtained by the formula: 1, 000 )( (A/2}
I (B/2). In the case of other terminal structures, the ratio of
each of the terminal structures can be obtained by replacing the
integral value in the above formula with _the integral value of
the peak assigned to each of the structures, with careful attention
20 to the ratio of hydrogen.
[Requirement (III)]
In the olefin resin (~), when the ratio (hereinafter, also
referred to as the ratio E) of a component (s) having a peak
temperature of a differential elution curve as measured by
- ---- - - _____ , •---- . -
SF-2911
32
cross-fractionation chromatography (CFC) using
a-dichlorobenzene as a solvent of less than 65°C, is taken as E
wt%, the value of "a" (hereinafter, also referred to as "value
a") represented by the following equation (Eq-1) is 1.4 or more,
5 preferably 1.6 or more, and more preferably 2.2 or more.
[0057]
a=(lOO-E)/P (E q -1)
The above mentioned differential elution curve is obtained
by differentiating a cumulative elution curve obtained in the
10 elution temperature range of from -20°C to 140°C. Further, by
separating the respective elution peaks observed in the
differential elution curve into normal distribution curves, the
ratio of the components corresponding to the respective elution
peaks can be obtained. In the measurement, when the ratio of a
15 component(s) soluble at less ·than -20°C (the ratio of a
component(s) which remain{s) uncoated on the beads inside the
temperature rising elution fractionation (TREF} column in the
r: cooling step of CFC measurement, even at -20°C} is taken as E(<-2o°C1
wt%; the sum of the ratios of eluted components having peaks within
ii 20 the range of -20°C or more and less than 65°C is taken as E(<65 °CJ
wt%; the sum of the ratios of eluted components having peaks within
wt%; the ratio of a component(s} insoluble at 140°C is taken as
--~ - • ------~ ____ , ·- -- ·,' .. -:-- . • -"--~ : .. _. :-o-c:-:,~--. - - - • ""--· ,
SF-2911
33
[0058]
In general, the total amount of the olefin resin ([3) is fully
soluble in a-dichlorobenzene at 140°C, and it is possible to detect
5 easily separable, clear peaks in the temperature range of 65°C
or more. Therefore, when E!>140 °C1 = 0, it is defined that E = 100
- E<~ 65 °C1. The detector to be used in the CFC measurement is
preferably an infrared spectrophotometer (detection wavelength:
3.42 pm).
10 [0059]
I
i
~
Regarding the ratio E and the ratio P with respect to the
total amount of the above mentioned olefin resin ([3), the "total
amountu refers only to the total amount of the resin obtained
through the polymerization step to be described later, and the
15 amounts of the resins, additives' and the like added thereto are
not included in the above described total amount.
[0060]
When the value a is within the above mentioned range, it
indicates that the olefin resin (~) contains a significant amount
20 of the grafted olefin polymer [Rl], namely, the ethylene/a-olefin
copolymer having the propylene polymer moiety as side chains.
i': [0061]
' ''
FIG. 4 shows a graph illustrating the relationship between
the ratio E (wt%), the ratio P (wt%) and the value a.
! -
'
i,
~~
-----------'----~--- _,_-_ --;c_,
SF-2911
34
[0062]
In FIG. 4, the dotted line indicating the relationship when
a = 1 illustrates the case where the grafted olefin polymer [Rl]
is not contained, in other words, in the case of a mixture of an
5 ethylene/a-olefin copolymer and a propylene polymer. On the
other hand, as the production efficiency of the grafted olefin
polymer [Rl] is increased, the value of the ratio E with respect
to the ratio Pis deCreased. As shown irt-FIG. 4, a higher value
of "a" indicates a higher production efficiency of the grafted
10 olefin polymer [Rl] . The olefin resin ( [3) according to the
present invention is characterized by having a "value a" of 1. 4
or more.
[0063]
In general, a corrunercially available olefin elastomer,
15 which is used as a polypropylene' resin modifier or the like, is
composed of an ethylene/a-olefin copolymer (such, as
ethylene/butene copolymer or ethylene/octene copolymer) , and is
a polymer in which the ethylene composition is adjusted to about
from 90 mol% to 50 mol%. Accordingly1 the ratio E of the soluble
20 component(s) in a common ethylene/a-olefin copolymer is
substantially 100%.
[0064]
When an olefin elastomer composed of the ethylene/ex-olefin
copolymer is added to the propylene resin, the olefin elastomer
-- - -_- "'-·----- _, ---
SF-2911
35
is dispersed in the propylene resin and plays a role to provide
an improved impact resistance. When the amount of the olefin
elastomer added is increased, although the impact resistance is
improved, the rigidity and the mechanical strength inherent to
5 the propylene resin are decreased. Thus, the impact strength and
the rigidity are usually conflicting physical properties in the
polypropylene resin composition.
[0065]
Since the olefin resin (\3) includes a high content of the
10 grafted olefin polymer [Rl] in which the chains of the crystalline
propylene polymer are chemically bound to the ethylene/a-olefin
copolymer, the resin is characterized by having a low ratio E
relative to the content of the ethylene/a-olefin copolymer.
[0066]
15 The addition of the olefin· resin (~) as described above to
a propylene resin results ~n _the formation_ 9f a phas_e-separated _
structure in which the ethylene/a-olefin copolymer is finely
dispersed in the propylene resin, because the polypropylene side
chains of the grafted olefin polymer [Rl] have a good compatibility
20 with the propylene resin. At this time, it is considered that
the polypropylene side chains of the grafted olefin polymer [Rl]
get in between the crystals of the propylene resin, at the
interface between the ethylene/a-olefin copolymer and the
propylene resin, which are mutually incompatible, thereby
SF-2911
36
exhibiting the effect of improving the strength at the interface.
Accordingly, the propylene composition including the olefin resin
{~) containing a high content of the grafted olefin polymer [Rl)
has an excellent impact resistance, a high rigidity and mechanical
5 strength, an excellent elongation, and a high surface hardness
when formed into a molded article, as well as a markedly improved
balance between each of the physical properties.
[ReqUirement (IV)]
The olefin resin (~) has a melting point (Tm) and a glass
10 transition temperature (Tg), as measured by differential scanning
calorimetry (DSC), within the range of from 120 to 165°C and within
the range of from -80 to -30°C, respectively.
[0067]
The melting point of the olefin resin ([3) is preferably from
15 130 to 160°C, and more preferably from 140°C to 160°C. In other
words, _the olefin re~in .([3)_ has a melting peak as measured by
differential scanning calorimetry (DSC) within the range of from
120 to 165°C, preferably from 130 to 160°C, and more preferably
:-: 20 [0068]
The temperature at which the above mentioned melting peak
is observed, namely, the melting point (Tm), and the heat of fusion
(~H) to be described later are obtained using DSC by: melting a
sample through a first temperature-increasing step; then allowing
i-
the melted sample to crystalize through a cooling step to 30°Ci
and subjecting the resultant to a second temperature-increasing
step (at a temperature rise rate of l0°C/min) and analyzing the
endothermic peak observed at this step.
5 [0069]
The melting point (Tm) observed within the above mentioned
range and the heat of fusion (~H) are mainly derived from the
polypropylene side chains of the grafted olefin polymer [Rl]
constituting the olefin resin (~). By having a melting point {Tm}
10 within the above mentioned range, and having a heat of fusion {~H)
preferably within the range to be described later, the olefin resin
(~) exhibits a good compatibility with the propylene resin, and
as a result, the propylene resin composition containing the olefin
resin (~) and the propylene polymer will have a good balance
15 between the rigidity, heat i:esistance, and toughness. The
melting point (Tm) can be adjusted within the above mentioned range,
for example, by adjusting the polymerization temperature or the
polymerization pressure in the produCtion s_tep (A) to be described
later.
20 [0070]
The glass transition temperature (Tg) of the olefin resin
(!3} is preferably from -80 to -40°C, and more preferably from-70°C to -50°C

CLAIMS
1. An olefin resin (~) satisfying the following requirements
(I) to (VI):
5 (I) the olefin resin ( ~) comprises a grafted olefin polymer
[Rl] comprising a main chain composed of an ethylene/a-olefin
copolymer and a side chain composed of a propylene polymer;
(II) whe-n the ratio of the amount of the propylene polymer
contained in the olefin resin (p} is taken as P wt%, the value
10 P is within the range of from 5 to 60;
(III) when the ratio of the amount of a component (s) having
a peak value of a differential elution curve as measured by
cross-fractionation chromatography (CFC) using
a-dichlorobenzene as a solvent of less than 65°C, to the amount
15 of the olefin resin (~) is taken as E wt%, the value a represented
by the following equation {Eq-1) is 1.4 or .. more;
a=(lOO-E)/P (E q -1)
{IV) the melting point (Tm) · and the glass transition
temperature (Tg) ' as measured by differential scanning
20 calorimetry (DSC), are within the range of from 120 to 165°C and
within the range of from -80 to -30°C, respectively;
(V) the hot xylene-insoluble content is less than 3 wt%;
and
(VI) the limiting viscosity [~] as measured in decalin at
135°C is within the range of from 0.5 to 5.0 dl/g.
2. The olefin resin ( ~) according to claim 1, wherein the ratio
of repeating units derived from ethylene with respect to the total
5 repeating units is within the range of from 20 to 80 mol%.
3. The olefin resin (~) according to claim 1 or 2, wherein the
propylene polymer constituting the side chain(s) of the grafted
olefin polymer [Rl] has an isotactic pentad fraction (mmmm) of
lD 93% or more.
4. The olefin resin (~) according to any one of claims 1 to
3, wherein the propylene polymer constituting the side chain(s)
of the grafted olefin polymer [Rl] has a weight average molecular
15 weight within the range of from ·s,ooo to 100,000.
5. The olefin resin (~) according to any one of claims 1 to
4, wherein the ethylene/a-olefin copOlymer constituting the main
chain of the grafted olefin polymer [Rl] has a weight average
20 molecular weight within the range of from 50,000 to 200,000.
6. The olefin resin (~} according to any one of claims 1 to
5, wherein the olefin resin (~) has a phase-separated structure
composed of a sea phase constituted by a non-crystalline component
and an island phase constituted by a crystalline component, and
wherein the particles of the island phase have an average diameter
as observed in a transmission electron microscope image within
the range of from 50 nm to 500 nm.
5
7. A method for producing the olefin resin (~) according to
any one of claims 1 to 6, the method comprising the following steps
(A) and (B):
(A) polymerizing propylene in the presence of an olefin
10 polymerization catalyst comprising a transition metal compound
[A] of a transition metal of Group 4 in the periodic table, the
compound comprising a ligand having a dimethylsilylbisindenyl
skeleton, to produce a polypropylene having terminal
unsaturation; and
15 (B) copolymerizing the polypropylene having terminal
unsaturation produced in the step (A), ethylene, and at least one
cx-olefin selected from ex-ole fins having from 3 to 20 carbon atoms,
in the presence of an olefin polymerization catalyst comprising
a bridged metallocene compound represented by the following
20 general formula [B]:
'·-~. ---- -_,_
SF-2911
184
R2 R3
R1 ~4
R14.... 1 1
R13,.......Y. Qi
R12 5
R1 !' R6
'=--
R'o R9 Rs R7
[B)
(wherein in the formula [ B] ,
a hydrogen atom, a hydrocarbon group, a silicon-containing group,
5 or a hetero atom-containing group other than silicon-containing
groups, and two mutually adjacent groups of the groups represented
by R1 to R4 are optionally bound together to form a ring;
R6 and R11 are the same atom or the same group selected from
hydrogen atom, hydrocarbon groups, silicon-containing groups,
10 and hetero atom-containing groups other than the
silicon-containing groups; R1 and R10 are the same atom or the same
group selected from hydrogen atom, hydrocarbon groups,
silicon-containing groups, and hetero atom-containing groups
other than the silicon-containing groups; R6 and R1 are optionally
15 bound together to form a ring; and R10 and R11 are optionally bound
together to form a ring; with the proviso that all of R6
, R7
, R10
and R11 are not hydrogen atoms;
R13 and R14 each independently represents an aryl group;
SF-2911
185
Y1 represents a carbon atom or a silicon atom;
M1 represents a zirconium atom or a hafnium atom;
Q represents a halogen atom, a hydrocarbon group, a
halogenated hydrocarbon group, a neutral conjugated or
5 non-conjugated diene having from 4 to 10 carbon atoms, an anionic
ligand, or a neutral ligand capable of being coordinated with a
lone pair of electrons;
j represents an integer of from 1 to 4; and
in cases where j is an integer of two or more, a plurality
10 of Qs may be the same as or different from each other).
8. The method for producing the olefin resin (~), according
to claim 7, wherein the step (B} is a solution polymerization
process carried out at a polymerization temperature of 90°C or
15 more.
20
9. A propylene resin composition comprising a propylene resin
(a) and the olefin resin (~) according to any one of claims 1 to
6.
10. The propylene resin composition according to claim 9,
comprising 50 to 98 parts by weight of the propylene resin (a)
and 2 to 50 parts by weight of the olefin resin {~) (wherein the
total amount of the propylene resin (a) and olefin resin (~) is
~' ,'t;
100 parts by weight).
11. The propylene resin composition according to claiffi 9 or 10,
wherein the olefin resin (~) is obtained by the method for
5 producing the olefin resin (~), according to claim 7 or 8.
12. A molded article obtainable from the propylene resin
composition according to any one of claims 9 to 11.