U.S. patent application number 09/842172 was filed with the patent office on 2001-09-27 for thermoplastic elastomer composition, powder or pellet of the same, and molded article comprising the same.
This patent application is currently assigned to Sumitomo Chemical Company, Limited. Invention is credited to Ejiri, Susumu, Nakatsuji, Yoshihiro, Sugimoto, Hiroyuki.
Application Number | 20010024717 09/842172 |
Document ID | / |
Family ID | 26577116 |
Filed Date | 2001-09-27 |
United States Patent
Application |
20010024717 |
Kind Code |
A1 |
Sugimoto, Hiroyuki ; et
al. |
September 27, 2001 |
Thermoplastic elastomer composition, powder or pellet of the same,
and molded article comprising the same
Abstract
A thermoplastic elastomer composition comprising 100 parts by
weight of a polyolefin resin, 5 to 250 parts by weight of a rubbery
polymer and 0 to 500 parts by weight of an ethylene-.alpha.-olefin
copolymer rubber, wherein a complex dynamic viscosity .eta.*(1) at
250.degree. C. is 1.5.times.10.sup.5 poise or less and a Newtonian
viscosity index n is 0.67 or less, and furthermore, wherein said
thermoplastic elastomer composition has a specific tan .delta.
peak, the peak temperature of which is different from that of the
polyolefin resin and that of the rubbery polymer, at a temperature
within the range from -70 to 30.degree. C. in a temperature
dependence curve of tan .delta. determined by solid dynamic
viscoelasticity measurement, powder or pellet thereof, and a molded
article thereof.
Inventors: |
Sugimoto, Hiroyuki; (Chiba,
JP) ; Nakatsuji, Yoshihiro; (Chiba, JP) ;
Ejiri, Susumu; (Chiba, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
Sumitomo Chemical Company,
Limited
|
Family ID: |
26577116 |
Appl. No.: |
09/842172 |
Filed: |
April 26, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09842172 |
Apr 26, 2001 |
|
|
|
08994776 |
Dec 19, 1997 |
|
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Current U.S.
Class: |
428/318.4 ;
428/304.4; 428/319.3; 525/240 |
Current CPC
Class: |
Y10T 428/249953
20150401; B29C 41/18 20130101; C08L 9/00 20130101; Y10T 428/249991
20150401; Y10T 428/249987 20150401; C08L 23/16 20130101; C08L 21/00
20130101; C08L 21/00 20130101; C08L 2666/06 20130101; C08L 23/16
20130101; C08L 2666/04 20130101 |
Class at
Publication: |
428/318.4 ;
525/240; 428/304.4; 428/319.3 |
International
Class: |
B32B 009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 20, 1996 |
JP |
08-341990 |
Dec 20, 1996 |
JP |
08-341989 |
Claims
What is claimed is:
1. A thermoplastic elastomer composition comprising 100 parts by
weight of a polyolefin resin, 5 to 250 parts by weight of a rubbery
polymer and 0 to 500 parts by weight of an ethylene-.alpha.-olefin
copolymer rubber, wherein said thermoplastic elastomer composition
has a specific tan .delta. peak, the peak temperature of which is
different from that of the polyolefin resin and that of the rubbery
polymer, at a temperature within the range from -70 to 30.degree.
C. in a temperature dependence curve of tan .delta. determined by
solid dynamic viscoelasticity measurement.
2. The thermoplastic elastomer composition according to claim 1,
wherein said thermoplastic elastomer composition has a complex
dynamic viscosity .eta.*(1) at 250.degree. C. of 1.5.times.10.sup.5
poise or less and a Newtonian viscosity index n of 0.67 or
less.
3. The thermoplastic elastomer composition according to claim 1,
wherein the rubbery polymer is a conjugated diene based elastomer
or a hydrogenated product thereof.
4. The thermoplastic elastomer composition according to claim 3,
wherein the conjugated diene based rubber polymer is a copolymer
rubber of a conjugated diene and the other monomer.
5. The thermoplastic elastomer composition according to claim 4,
wherein the copolymer rubber of the conjugated diene and other
monomer is selected from the group consisting of conjugated
diene-aromatic vinyl compound copolymer rubbers, conjugated
diene-vinyl ester copolymer rubbers, conjugated diene-ethylenically
unsaturated carboxylic acid ester copolymer rubbers and conjugated
diene-vinyl nitrile copolymer rubbers.
6. The thermoplastic elastomer composition according to claim 4,
wherein the content of the other monomer unit in the copolymer
rubber of the conjugated diene and other monomer is 50% by weight
or less.
7. The thermoplastic elastomer composition according to claim 1,
wherein the peak temperature of the specific tan .delta. peak is
lower than the tan .delta. peak temperature of the polyolefin
resin.
8. The thermoplastic elastomer composition according to claim 1,
wherein the melt flow rate of the rubbery polymer is at least 5
g/10 min.
9. A molded article obtained by powder molding powder of the
thermoplastic elastomer composition of claim 1.
10. A two-layer molded article comprising the molded article of
claim 9 and a foamed layer, the foamed layer being laminated on at
least one surface of the molded article.
11. A multi-layer molded article comprising the molded article of
claim 9 and a thermoplastic resin core material, the thermoplastic
resin core material being laminated on at least one surface of the
molded article.
12. A multi-layer molded article comprising the two-layer molded
article of claim 10 and a thermoplastic resin core material, the
thermoplastic resin core material being laminated on the foamed
layer surface of the two-layer molded article.
13. A method for producing the multi-layer molded article of claim
11, which comprises feeding a thermoplastic resin melt on one
surface of the molded article of claim 9, followed by pressing.
14. A method for producing the multi-layer molded article of claim
12, which comprises feeding a thermoplastic resin melt on one
foamed layer surface of the two-layer molded article of claim 10,
followed by pressing.
15. A method for producing the multi-layer molded article of claim
11, which comprises feeding the molded article of claim 9 between a
pair of opened molds and clamping both molds after or while feeding
a thermoplastic resin melt between one surface of the molded
article and the mold which is opposed to the surface.
16. A method for producing the multi-layer molded article of claim
12, which comprises feeding the two-layer molded article of claim
10 between a pair of opened molds and clamping both molds after or
while feeding a thermoplastic resin melt between the foamed layer
of the molded article and the mold which is opposed to the foamed
layer.
17. A thermoplastic elastomer composition pellet having a
sphere-reduced average diameter of 1.2 mm or less and a bulk
specific gravity of at least 0.38, which is composed of a
thermoplastic elastomer composition comprising 100 parts by weight
of a polyolefin resin, 5 to 250 parts by weight of a rubbery
polymer and 0 to 500 parts by weight of an ethylene-.alpha.-olefin
copolymer rubber, and having a complex dynamic viscosity .eta.*(1)
at 250.degree. C. of 5.0.times.10.sup.4 poise or less and a
Newtonian viscosity index n of 0.28 or less, wherein said
thermoplastic elastomer composition has a specific tan .delta.
peak, the peak temperature of which is different from that of the
polyolefin resin and that of the rubbery polymer, at a temperature
within the range from -70 to 30.degree. C. in a temperature
dependence curve of tan .delta. determined by solid dynamic
viscoelasticity measurement.
18. The thermoplastic elastomer composition pellet according to
claim 17, wherein the rubbery polymer is a conjugated diene based
elastomer or a hydrogenated product thereof.
19. The thermoplastic elastomer composition pellet according to
claim 18, wherein the conjugated diene based rubber polymer is a
copolymer rubber of a conjugated diene and the other monomer.
20. The thermoplastic elastomer composition pellet according to
claim 19, wherein the copolymer rubber of the conjugated diene and
other monomer is a member selected from the group consisting of
conjugated diene-aromatic vinyl compound copolymer rubbers,
conjugated diene-vinyl ester copolymer rubbers, conjugated
diene-ethylenically unsaturated carboxylic acid ester copolymer
rubbers and conjugated diene-vinyl nitrile copolymer rubbers.
21. The thermoplastic elastomer composition pellet according to
claim 17, wherein the content of the other monomer unit in the
copolymer rubber of the conjugated diene and other monomer is 50%
by weight or less.
22. The thermoplastic elastomer composition pellet according to
claim 17, wherein the peak temperature of the new tan .delta. peak
is lower than the tan .delta. peak temperature of the polyolefin
resin.
23. The thermoplastic elastomer composition pellet according to
claim 17, wherein the peak intensity of the new tan .delta. peak is
at least 0.05.
24. The thermoplastic elastomer composition pellet according to
claim 17, wherein the melt flow rate of the thermoplastic elastomer
is at least 5 g/10 min.
25. A molded article obtained by powder molding the thermoplastic
elastomer composition pellet of claim 17.
26. A two-layer molded article comprising the molded article of
claim 25 and a foamed layer, the foamed layer being laminated on at
least one surface of the molded article.
27. A multi-layer molded article comprising the molded article of
claim 25 and a thermoplastic resin core material, the thermoplastic
resin core material being laminated on at least one surface of the
molded article.
28. A multi-layer molded article comprising the two-layer molded
article of claim 26 and a thermoplastic resin core material, the
thermoplastic resin core material being laminated on the foamed
layer surface of the two-layer molded article.
29. A method for producing a multi-layer molded article, which
comprises feeding a thermoplastic resin melt on one surface of the
molded article of claim 25, followed by pressing.
30. A method for producing a multi-layer molded article, which
comprises feeding a thermoplastic resin melt on the surface of the
foamed layer of the two-layer molded article of claim 26, followed
by pressing.
31. A method for producing a multi-layer molded article, which
comprises feeding the molded article of claim 25 between a pair of
opened molds and clamping both molds after or while feeding a
thermoplastic resin melt between the surface of the molded article
and the mold opposed to the surface.
32. A method for producing a multi-layer molded article, which
comprises feeding the two-layer molded article of claim 26 between
a pair of opened molds and clamping both molds after or while
feeding a thermoplastic resin melt between the foamed layer of the
two-layer molded article and the mold opposed to the surface.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a thermoplastic elastomer
composition, powder or pellet of the same, and a molded article
comprising the same.
[0003] 2. Description of the Related Art
[0004] Hitherto, a molded article having minute uneven decorations
such as leather grain and stitch on its surface is used as a skin
material of an interior material of an automobile, and the like. As
the skin material, a vinyl chloride resin molded article of a vinyl
chloride resin or a composition comprising the vinyl chloride resin
as a main component is widely known. However, hydrogen chloride gas
and the like are generated when such vinyl chloride resin molded
articles are incinerated after the use, and induce a problem that
special incinerators are required.
[0005] As those for solving such problems, a molded article of a
composition comprising a polyolefin resin and an
ethylene-.alpha.-olefin copolymer rubber is proposed (JP-A-05-1183
and JP-A-05-5050). However, such molded article tends to cause
whitening on bending compared with the vinyl chloride resin molded
article. Therefore, when the molded article is released from the
mold after molding or formed into a predetermined shape, the bent
portion tends to cause whitening, which results in poor appearance.
Also, there is a problem that the feeling is inferior because of
poor flexibility.
[0006] To solve the above described problems, the present inventors
have intensively studied to develop a thermoplastic elastomer
composition which scarcely causes whitening on bending and can
provide a molded article excellent in flexibility. As a result, the
present inventors have found that a thermoplastic elastomer
composition comprising a polyolefin resin, a rubbery polymer and
optionally an ethylene-.alpha.-olefin copolymer rubber, having a
peak at a specific peak temperature in a temperature dependence
curve of tan .delta. determined by a solid dynamic viscoelasticity
measurement, does not cause whitening on bending and can provide a
molded article excellent in flexibility. The present inventors have
also found that a thermoplastic elastomer composition pellet having
specific pellet physical properties can give a molded article
having complicated shapes without causing neither pinholes nor
wormholes and the resulting molded article has an excellent
feeling. Thus, the present invention has been achieved.
SUMMARY OF THE INVENTION
[0007] An object of the present invention is to provide a
thermoplastic elastomer composition which scarcely causes whitening
and provides a molded article excellent in flexibility.
[0008] Another object of the present invention is to provide a
thermoplastic elastomer composition powder or pellet which can
easily give a molded article having a complicated shape and an
excellent feeling, which scarcely causes whitening on bending.
[0009] Other objects of the present invention will become apparent
from the following description.
[0010] According to the present invention, there is provided a
thermoplastic elastomer composition comprising 100 parts by weight
of a polyolefin resin, 5 to 250 parts by weight of a rubbery
polymer and 0 to 500 parts by weighs of an ethylene-.alpha.-olefin
copolymer rubber, wherein said thermoplastic elastomer composition
has a new tan .delta. peak, the peak temperature of which is
different from that of the polyolefin resin and that of the rubbery
polymer, at a temperature within the range from -70 to 30.degree.
C. in a temperature dependence curve of tan .delta. determined by
solid dynamic viscoelasticity measurement.
[0011] According to the present invention, there is also provided a
thermoplastic elastomer composition powder having the above
described composition, a complex dynamic viscosity .eta.*(1) at
250.degree. C. of 1.5.times.10.sup.5 poise or less and a Newtonian
viscosity index n of 0.67 or less, wherein said thermoplastic
elastomer composition has a specific tan .delta. peak, the peak
temperature of which is different from that of the polyolefin resin
and that of the rubbery polymer, at a temperature within the range
from -70 to 30.degree. C. in a temperature dependence curve of tan
.delta. determined by solid dynamic viscoelasticity
measurement.
[0012] Furthermore, according to the present invention, there is
provided a thermoplastic elastomer composition pellet having a
sphere-reduced average diameter of 1.2 mm or less and a bulk
specific gravity of at least 0.38, which is composed of a
thermoplastic elastomer composition having the above described
composition, wherein a complex dynamic viscosity .eta.*(1) at
250.degree. C. is 5.0.times.10.sup.4 poise or less and a Newtonian
viscosity index n is 0.28 or less, and said thermoplastic elastomer
composition having a specific tan .delta. peak, the peak
temperature of which is different from that of the polyolefin resin
and that of the rubbery polymer, at a temperature within the range
from -70 to 30.degree. C. in a temperature dependence curve of tan
.delta. determined by solid dynamic viscoelasticity
measurement.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a cross sectional view of an example of a slush
molding apparatus in which a container containing a thermoplastic
elastomer composition powder for powder slush molding and a mold
for slush molding are in an integrated state.
[0014] FIG. 2 is a plain view of a mold for slush molding.
[0015] FIG. 3 is a cross sectional view of a molded article.
DETAILED DESCRIPTION OF THE INVENTION
[0016] The polyolefin resin used in the present invention is a
crystalline homopolymer or copolymer obtained by homopolymerizing
an olefin or copolymerizing at least two olefins. The crystallinity
is preferably at least 50%. Examples of the olefin are olefins
having 2 to 8 carbon atoms, such as ethylene, propylene, butene-1
and the like. Examples of the homopolymer or copolymer are
polyethylene, polypropylene, a copolymer of propylene and ethylene,
a copolymer of propylene and .alpha.-olefin other than propylene,
for example, butene-1, and the like. Among them, a copolymer of
propylene and ethylene is preferable because a thermoplastic
elastomer composition which provides a molded article with
excellent heat resistance and flexibility can be obtained. The
polyolefin resin may be crosslinked. A melt flow rate (value
measured at 230.degree. C. under a load of 2.16 kgf according to
JIS K-7210, hereinafter referred to as ("MFR") is preferably from
20 to 300 g/10 min., more preferably from 50 to 300 g/10 min.,
particularly from 100 to 300 g/10 min. because a molded article
excellent in appearance and strength can be obtained when a molded
article is produced by powder molding the powder or pellet of
thermoplastic elastomer composition of the present invention.
[0017] Examples of the rubbery polymer include a conjugated diene
based elastomer, a hydrogenated product thereof and the like.
[0018] The conjugated diene based elastomer is a conjugated diene
polymer rubber or a conjugated diene copolymer rubber.
[0019] The conjugated diene polymer rubber is a copolymer rubber
prepared by homopolymerizing a conjugated diene or copolymerizing
at least two conjugated dienes, and examples of the conjugated
diene include conjugated dienes having 4 to 8 carbon atoms such as
butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene and the
like. Examples of the conjugated diene homopolymer or copolymer
rubber include polybutadiene, polyisoprene, polypentadiene,
butadiene-isoprene copolymer and the like.
[0020] The conjugated copolymer rubber is a copolymer rubber of the
same conjugated diene as that described above and a monomer other
than the conjugated diene. Examples of the monomer other than the
conjugated diene include vinyl aromatic compound, vinyl ester
compounds, vinyl nitrile compound, ethylenically unsaturated
carboxylic acid ester and the like. Among them, a vinyl aromatic
compound is preferable.
[0021] Regarding the vinyl aromatic compound, the 1- or 2-position
of a vinyl group may be substituted with an alkyl group such as
methyl group and the like. Examples of the vinyl aromatic compound
include vinyl aromatic compounds having 8 to 12 carbon atoms such
as styrene, p-methylstyrene, .alpha.-methylstyrene and the like.
Examples of the vinyl ester compound include Vinyl acetate and the
like. Examples of the ethylenically unsaturated carboxylic acid
ester include methyl methacrylate, ethyl methacrylate, methyl
acrylate, ethyl acrylate, butyl acrylate and the like. Examples of
the vinyl nitrile compound are acrylonitrile, methacrylonitrile and
the like.
[0022] Examples of the conjugated diene copolymer rubber include
conjugated diene-vinyl aromatic compound copolymer rubbers such as
a butadiene-styrene copolymer rubber, an isoprene-styrene copolymer
rubber, a butadiene-p-methylstyrene copolymer rubber and the like;
conjugated diene-vinyl ester compound copolymer rubbers such as a
butadiene-methyl methacrylate copolymer rubber, a butadiene-methyl
acrylate copolymer rubber and the like; and conjugated diene-vinyl
nitrile compound copolymer rubbers such as a
butadiene-acrylonitrile copolymer rubber and the like.
[0023] The hydrogenated product of conjugated diene based elastomer
(hereinafter, sometimes referred to as "hydorogenated conjugated
diene based elastomer") includes a hydrogenated conjugated diene
polymer rubber and a hydrogenated conjugated diene copolymer rubber
prepared by hydrogenating the above conjugated diene polymer rubber
or a conjugated diene copolymer rubber, and examples of the
hydrogenated conjugated diene rubbery polymer include hydrogenated
ones of the above conjugated diene rubbery polymers.
[0024] These rubbery polymers can be produced by a method described
in JP-A-02-36244, JP-A-03-72512, JP-A-07-118335 or the like.
[0025] In the conjugated copolymer rubber or hydrogenated
conjugated diene copolymer rubber, the content of the monomer unit
other than the conjugated diene is preferably 50% by weight or less
because a molded article having an excellent flexibility is
obtained.
[0026] When the hydrogenated conjugated diene based rubbery
polymers is used as the rubbery polymer, the proportion of the
number of hydrogenated conjugated diene units having a side chain
with at least two carbon atoms to the total number of hydrogenated
conjugated diene units is preferably at least 45%, more preferably
from 60 to 95%, particularly preferably from 70 to 90%, because the
thermoplastic elastomer composition of the present invention is
easily obtained. The proportion can be determined by .sup.1H-NMR
measurement.
[0027] MFR of the rubbery polymer is preferably at least 5 g/10
min., more preferably at least 10 g/10 min., because a molded
article excellent in strength can be obtained when the molded
article is produced by powder molding the powder or pellet of the
thermoplastic elastomer composition of the present invention.
[0028] The rubbery polymers may be used alone or in combination
thereof, and the content is within the range from 5 to 250 parts by
weight, preferably from 10 to 150 parts by weight per 100 parts by
weight of the polyolefin resin.
[0029] The thermoplastic elastomer composition of the present
invention may contain an ethylene-.alpha.-olefin copolymer rubber.
When the ethylene-.alpha.-olefin copolymer rubber is contained, a
thermoplastic elastomer composition having a lower brittle
temperature, in other words, an excellent cold resistance, is
provided, favorably.
[0030] The ethylene-.alpha.-olefin copolymer rubber is a copolymer
of ethylene and .alpha.-olefin, or a copolymer of ethylene,
.alpha.-olefin and non-conjugated diene, which is a polymer having
little crystallinity or a crystallinity of less than 50%. Examples
of the .alpha.-olefin include .alpha.-olefins having 3 to 10 carbon
atoms such as propylene, 1-butene, 3-methyl-1-butene and the like.
Examples of the non-conjugated diene include non-conjugated dienes
having 5 to 15 carbon atoms, such as dicyclopentadiene,
2-ethylidene-5-norbornene, 1,4-hexadiene, 1,5-cyclooctadiene,
2-methylene-5-norbornene and the like. Examples of the
ethylene-.alpha.-olefin copolymer rubber include an
ethylene-propylene copolymer rubber, an
ethylene-propylene-2-ethylidene-5- -norbornene copolymer rubber
(hereinafter, referred to as "EPDM") and the like. The
ethylene-.alpha.-olefin copolymer rubber may be crosslinked.
[0031] The content of the ethylene-.alpha.-olefin copolymer rubber
is within the range from 0 to 500 parts by weight, preferably 20 to
200 parts by weight per 100 parts by weight of the polyolefin
resin.
[0032] The thermoplastic elastomer composition of the present
invention can be produced, for example, by melt-kneading the
polyolefin resin, the rubbery polymer and optionally the
ethylene-.alpha.-olefin copolymer rubber.
[0033] When the ethylene-.alpha.-olefin copolymer rubber is
crosslinked, the thermoplastic elastomer composition is produced
either by kneading the uncrosslinked ethylene-.alpha.-olefin
copolymer rubber, the polyolefin resin and a crosslinking agent to
effect dynamic crosslinking followed by adding a rubbery polymer by
kneading, or kneading the uncrosslinked ethylene-.alpha.-olefin
copolymer rubber, the polyolefin resin, the rubbery polymer and a
crosslinking agent to effect dynamic crosslinking.
[0034] Examples of the crosslinking agent include organic peroxides
such as 2,5-dimethyl-2,5-di(t-butylperoxy) hexane and the like. The
amount of the crosslinking agent is usually 1 part by weight or
less, preferably 0.8 part by weight or less per 100 parts by weight
of the total weight of the ethylene-.alpha.-olefin copolymer rubber
and the polyolefin resin.
[0035] When the dynamic crosslinking is performed by using the
crosslinking agent in the presence of a crosslinking aid, the
ethylene-.alpha.-olefin copolymer is suitably crosslinked, and a
thermoplastic elastomer composition excellent in heat resistance
and melt flow property, can be obtained.
[0036] Examples of the crosslinking aid include a bismaleimide
compound and the like, and the amount of the crosslinking aid used
is usually 1.5 parts by weight or less, preferably 0.8 parts by
weight or less per 100 parts by weight of total weight of the
ethylene-.alpha.-olefin copolymer rubber and the polyolefin resin.
When the crosslinking aid is used, the amount of the crosslinking
agent used is usually 0.8 part by weight or less, preferably 0.6
part by weight or less, per 100 parts by weight of the total weight
of the ethylene-.alpha.-olefin copolymer rubber and the polyolefin
resin.
[0037] In the dynamic crosslinking, the components may be kneaded
with heating at the temperature of from 150 to 250.degree. C. using
a kneader such as a single-screw kneader, a twin-screw kneader or
the like.
[0038] By the dynamic crosslinking, the ethylene-.alpha.-olefin
copolymer rubber is preferentially crosslinked. The polyolefin
resin is sometimes crosslinked. When the ethylene-.alpha.-olefin
copolymer rubber, the polyolefin resin and the rubbery polymer are
dynamically crosslinked after kneading, the rubbery polymer is
sometimes crosslinked.
[0039] The thermoplastic elastomer composition of the present
invention may contain various additives, for example, mineral oil
softeners; thermal stabilizers such as phenol stabilizers, sulfite
stabilizers, phenylalkane stabilizers, phosphite stabilizers, amine
stabilizers, amide stabilizers, and the like; anti-aging agents;
light stabilizers; anti-static agents; lubricants such as a metal
soap, a wax and the like; internal mold release agents such as
silicone compounds (e.g. a dimethylpolysiloxane compound) and the
like; and pigments.
[0040] It may also contain other polymer components, for example,
rubbers such as a copolymer rubber of propylene and .alpha.-olefin
having at least 4 carbon atoms, natural rubber, butyl rubber,
chloroprene rubber, epichlorohydrin rubber, acrylic rubber and the
like, ethylene-acrylic acid copolymer, ethylene-vinyl acetate
copolymer and a saponified one thereof, ethylene-methyl
methacrylate copolymer, ethylene-glycidyl methacrylate-vinyl
acetate copolymer, ethylene-glycidyl methacrylate-vinyl acetate
copolymer and the like.
[0041] These additives and other polymer components may be
previously contained either in the polyolefin resin, the rubbery
polymer or the ethylene-.alpha.-olefin copolymer, or may be blended
at the time of the above kneading or dynamic crosslinking or after
it.
[0042] Among them, the mineral oil softener is preferably used
because the thermoplastic elastomer composition containing the
mineral oil softener is superior in melt flow property and can
provide a molded article having an excellent flexibility.
[0043] The preferable range of a complex dynamic viscosity
.eta.*(1) at 250.degree. C. of the thermoplastic elastomer
composition of the present invention varies depending on the
molding method adopted in the production of the molded article. For
example, in the case of powder of a thermoplastic elastomer
composition produced by a freeze-pulverization method described
below, used for a powder molding, the complex dynamic viscosity
.eta.*(1) at 250.degree. C. is preferably 1.5.times.10.sup.5 poise
or less, more preferably 1.times.10.sup.2 to 5.times.10.sup.3
poise, most preferable 3.times.10.sup.2 to 3.times.10.sup.3 poise
from a view point of processability.
[0044] And, in a case of pellet of a thermoplastic elastomer
composition produced by a solvent-treatment method, a strand-cut
method or a die-face cut method described below, used for a powder
molding, the complex dynamic viscosity .eta.*(1) at 250.degree. C.
is preferably 5.0.times.10.sup.4 poise or less, more preferably
1.times.10.sup.2 to 3.0.times.10.sup.3 poise, most preferably
3.times.10.sup.2 to 2.times.10.sup.3 poise or less from a view
point of processability.
[0045] The complex dynamic viscosity .eta.*(.omega.) is a value
calculated by using a storage rigidity G'(.omega.) and loss
rigidity G"(.omega.) at 250.degree. C. and at a vibration frequency
of .omega. according to the calculation formula (1):
.eta.*(.omega.)={[G'(.omega.)]2+[G"(.omega.)]2}.sup.1/2/.omega.
(1)
[0046] and the complex dynamic viscosity .eta.*(1) is a complex
dynamic viscosity at .omega. of 1 radian/second.
[0047] When the complex dynamic viscosity .eta.*(1) in the each
case above, exceeds the upper limit specified, the melt flow
property of the thermoplastic elastomer composition becomes poor
and it tends to become difficult to produce a molded article by a
molding method in which the shear rate on molding is usually as low
as 1 sec.sup.-1 or less, such as the powder molding.
[0048] Further, in the case of powder of a thermoplastic elastomer
composition produced by the freeze-pulverization method described
below, used for a powder molding, the Newtonian viscosity index n
is preferably 0.67 or less, more preferably 0.01 to 0.35, most
preferably 0.03 to 0.25 from a view point of processability.
[0049] And, in a case of pellet of a thermoplastic elastomer
composition produced by the solvent-treatment method, strand cut
method or die-face cut method described below, used for a powder
molding, the Newtonian viscosity index n is preferably 0.28 or
less, more preferably 0.01 to 0.25, most preferably 0.03 to
0.20.
[0050] Herein, the Newtonian viscosity index n is a value
calculated by using the above complex dynamic viscosity .eta.*(1)
and a complex dynamic viscosity .eta.*(100) measured at 250.degree.
C. and a vibration frequency .omega. of 100 radian/second according
to the formula (2):
n={log .eta.*(1)-log .eta.*(100)}/2 (2)
[0051] When the Newtonian viscosity index n exceeds each upper
limit, the mechanical strength of the resulting molded article
tends to become very poor, unfavorably.
[0052] To produce the thermoplastic elastomer composition of the
present invention which satisfies the values of physical properties
represented by the above complex dynamic viscosity and the
Newtonian viscosity index, the degree of the kneading and dynamic
crosslinking, the kind and amount of the respective components
constituting the thermoplastic elastomer composition, the kinds and
amounts of the crosslinking agent and crosslinking aid in the
dynamic crosslinking, and the kinds and amounts of the additives
are suitably selected.
[0053] Among them, the influence of the shear rate in the kneading
and dynamic crosslinking exerted on the above values of physical
properties is large, and the kneading and dynamic crosslinking is
preferably performed at the shear rate of at least 1.times.10.sup.3
sec.sup.-1.
[0054] It is necessary that the thermoplastic elastomer composition
of the present invention has a specific tan .delta. peak, the peak
temperature of which is different from that of the polyolefin resin
and that of the rubbery polymer, at the temperature within the
range from -70 to 30.degree. C. in a temperature dependence curve
of tan .delta. determined by solid dynamic viscoelasticity
measurement.
[0055] The solid viscoelasticity can be measured by using a
conventional solid viscoelasticity measuring apparatus.
[0056] The peak temperature of the specific tan .delta. peak may be
only different from that of the polyolefin resin and that of the
rubbery polymer, but furthermore, is usually lower than the peak
temperature of the polyolefin resin.
[0057] When the thermoplastic elastomer composition doesn't have a
specific peak, the molded article tends to cause whitening easily
when it is bent. To obtain the effect sufficiently, the peak
intensity of the new peak is preferably at least 0.05.
[0058] The molded article obtained by molding the thermoplastic
elastomer composition of the present invention doesn't easily cause
whitening, but the method for producing the molded article is not
specifically limited, and examples thereof include powder molding,
press molding, extrusion molding, injection molding, vacuum molding
and the like.
[0059] In the production of the molded article, the composition of
the present invention is used after previously forming into pellet,
powder or the like. To produce a molded article by powder molding,
powder of the thermoplastic elastomer composition of the present
invention may be subjected to powder molding.
[0060] As the method for forming the thermoplastic elastomer
composition into powder, various methods can be used. It is
possible to produce the powder easily by a freeze-pulverization
method, wherein the thermoplastic elastomer composition is cooled
below the glass transition temperature, preferably -70.degree. C.
or less, more preferably -90.degree. C. or less, and ground in such
a cooled state. When the thermoplastic elastomer composition is
ground at the temperature higher than the glass transition
temperature, the particle size distribution of the obtained powder
tends to become broad and it becomes difficult to perform powder
molding. To grind while maintaining the cooled state of the
thermoplastic elastomer composition, it is preferable to grind by a
method which has a good pulverization efficiency and cooling
efficiency. For example, a mechanical pulverization method using an
impact grinder such as a ball mill or the like is used. The powder
obtained by this method has a particle size enough to pass a Tyler
standard sieve of 24 mesh (opening of 700 .mu.m.times.700 .mu.m),
preferably 28 mesh (opening of 590 .mu.m.times.590 .mu.m).
[0061] In the case of pellet of the thermoplastic elastomer
composition produced by the solvent-treatment method, strand cut
method or die-face cut method described below, when pellet, having
a sphere-reduced average diameter of 1.2 mm or less and a bulk
specific gravity of at least 0.38, is used for powder molding,
there can be obtained a molded article having a complicated shape
such as a convex portion and being free from a drawback such as
wormholes, pinhole and the like.
[0062] Herein, the sphere-reduced average diameter means a particle
diameter calculated as the diameter of a sphere which has the same
volume as an average volume of the pellet of the thermoplastic
elastomer composition. The average volume of the particles is a
value obtained by calculating from the total weight of a hundred
pellets of the arbitrary selected thermoplastic elastomer
composition and the density of the thermoplastic elastomer
composition, and is preferably 1.0 mm or less. When the
sphere-reduced average diameter exceeds 1.2 mm, heat fusion of the
pellet on powder molding becomes insufficient, and the resulting
molded article has pinholes or wormholes.
[0063] The bulk specific gravity is a value calculated from the
weight of 100 ml of the pellet of the thermoplastic elastomer
composition fed to a container for measuring bulk specific gravity
from a funnel for measuring bulk specific gravity according to JIS
K-6721, and is preferably at least 0.42. When the bulk specific
gravity is less than 0.38, adhesion of the pellet onto the molding
surface in the powder molding tends to become insufficient and the
molded article tends to have pinholes or wormholes, which results
in poor appearance.
[0064] The thermoplastic elastomer powder having such powder
physical properties can be easily produced, for example, by a
method of melting a thermoplastic elastomer composition with
heating, extruding the molten thermoplastic elastomer composition
from a die to form a strand, drawing an extruded strand or drawing
it with stretching, followed by cooling and cutting (hereinafter
referred to as "strand-cut method" (for example, JP-A-50-149747)),
a method of grinding a thermoplastic elastomer composition at the
temperature lower than the glass transition point, and treating the
ground thermoplastic elastomer composition with a poor solvent to
form spheres (hereinafter referred to as "solvent-treatment method"
(for example, JP-A-62-280226)) and a method of melting a
thermoplastic elastomer composition with heating, extruding the
molten thermoplastic elastomer composition into water and cutting
it immediately after passing through a discharge opening of the die
(hereinafter referred to as "die-face cut method").
[0065] In case of producing by the strand-cut method, a diameter of
a discharge opening of the die is usually within the range from 0.1
to 3 mm, preferably from 0.2 to 2 mm. A discharge rate from the die
is usually within the range from 0.1 to 5 kg/hour/opening,
preferably from 0.5 to 3 kg/hour/opening. A haul-off rate of a
strand is usually within the range from 1 to 100 m/min., preferably
from 5 to 50 m/min. A cut length after cooling is usually 1.4 mm or
less, preferably 1.2 mm or less.
[0066] When the pellet is produced by the solvent-treatment method,
the thermoplastic elastomer composition is ground at a temperature
lower than its glass transition point, usually -70.degree. C. or
less, preferably -90.degree. C. or less, and then solvent-treated.
The term "solvent treatment" used herein means a method of heating
the ground thermoplastic elastomer composition in a solvent which
has a low compatibility with the thermoplastic elastomer in the
presence of a dispersant and an emulsifier to the temperature
higher than a melt temperature of thermoplastic elastomer
composition, preferably higher than the melt temperature by 30 to
50.degree. C. to form spheres, followed by cooling and
removing.
[0067] Examples of the medium used in the solvent treatment include
ethylene glycol, polyethylene glycol, polypropylene glycol and the
like, and the amount is within the range from 300 to 1000 parts by
weight, preferably from 400 to 800 parts by weight, per 100 parts
by weight of the thermoplastic elastomer composition to be
used.
[0068] Examples of the dispersant include ethylene-acrylic acid
copolymer, silicic anhydrate, titanium oxide and the like, and the
amount is usually within the range from 5 to 20 parts by weight,
preferably from 10 to 15 parts by weight, per 100 parts by weight
of the thermoplastic elastomer composition.
[0069] Examples of the emulsifier include polyoxyethylene sorbitan
monolaurate, polyethylene glycol monolaurate, sorbitan tristearate
and the like but are not limited thereto. The amount is usually
within the range from 3 to 15 parts by weight, preferably from 5 to
10 parts by weight, per 100 parts by weight of the thermoplastic
elastomer composition.
[0070] In case of producing by the die-face cut method, a diameter
of a discharge opening is usually within the range from 0.1 to 3
mm, preferably from 0.2 to 2 mm. A discharge rate from a die is
usually within the range from 0.1 to 5 kg/hour/opening, preferably
from 0.5 to 3 kg/hour/opening.
[0071] A molded article obtained by molding the powder or the
pellet of the thermoplastic elastomer composition, which satisfies
the above conditions, scarcely causes whitening. As the molding
method, a powder molding is suitable, but the other methods such as
a press molding, an extrusion molding, an injection molding, a
vacuum forming and the like can also be applied.
[0072] Since the above powder or the pellet of the thermoplastic
elastomer composition can be easily molten by heat supplied from
the mold even at a low shear rate and a low molding pressure as in
case of powder molding method, the powder can be easily molded into
various shapes. Examples of the powder molding method include a
fluidization dip method, an electrostatic coating method, a powder
spray method, a powder rotational molding method, a powder slush
molding method and the like.
[0073] To perform powder molding the powder or pellet of the
thermoplastic elastomer composition, for example, a mold whose
molding surface may be provided with a complicated pattern is
heated to a temperature higher than the melt temperature of the
thermoplastic elastomer composition, and then powder or pellet of
the thermoplastic elastomer composition is fed onto the molding
surface of the mold. The powder or the pellet is molten and adhered
each other to obtain a sheet-like melt on the molding surface and
the excess amount of unadhered powder or the pellet is dropped off
from the mold. After dropping off the powder or the pellet, the
mold may be further heated. Then, the mold is cooled, and the
molded article is released from the mold.
[0074] Examples of the heating method of the mold include a gas
heating furnace method, a heat transfer medium-circulation method,
a dipping system into a heat transfer medium oil or a heated
fluidized sand, a microwave induction heating system and the
like.
[0075] A mold temperature in case of heat-fusing the powder onto
the mold is usually within the range from 150 to 300.degree. C.,
preferably from 190 to 270.degree. C. A time period of slushing the
powder or the pellet onto the molding surface of the mold is not
particularly limited and properly selected depending on the size
and thickness of the molded article.
[0076] A foamed material having an excellent flexibility can be
produced by molding the thermoplastic elastomer composition
containing a foaming agent. The method for producing such molded
article is not specifically limited, and examples thereof include
powder molding, press molding, extrusion molding, injection molding
and the like.
[0077] For example, to produce a foamed article by the powder
molding, powder of the thermoplastic elastomer composition powder
containing a foaming agent may be foamed after powder molding.
[0078] As the foaming agent, a thermal decomposition type foaming
agent is usually used. Examples of the thermal decomposition type
foaming agent include azo compounds such as azodicarbonamide,
2,2'-azobisisobutyronitri- le, diazodiaminobenzene and the like;
sulfonyl hydrazide compounds such as benzenesulfonyl hydrazide,
benzene-1,3-sulfonyl hydrazide, p-toluenesulfonyl hydrazide and the
like.; nitroso compounds such as
N,N'-dinitrosopentamethylenetetramine,
N,N'-dinitroso-N,N'-dimethyltereph- thalamide and the like; azide
compounds such as teraphthalazide and the like; and carbonates such
as sodium hydrogencarbonate, ammonium hydrogencarbonate, ammonium
carbonate, and the like. Among them, azodicarbonamide is preferably
used.
[0079] Examples of the method for producing the powder or the
pellet of the thermoplastic elastomer composition containing the
foaming agent include a method of mixing a foaming agent with
powder or pellet of thermoplastic elastomer composition, and a
method of previously kneading a thermoplastic elastomer composition
with a foaming agent at a temperature lower than its decomposition
temperature of the foaming agent, followed by grinding by the above
method. A foaming aid, a cell adjuster and the like may be mixed,
together with the foaming agent.
[0080] The molded article obtained by molding the thermoplastic
elastomer composition of the present invention is useful as a skin
material, and a two-layer molded article obtained by laminating a
foamed layer on one surface of the molded article may also be used
as the skin material. Such two-layer molded article can be
integrally produced by powder molding method (for example,
JP-A-05-473) and may also be produced by bonding a separately
produced foamed material to the above obtained molded article using
a bonding agent.
[0081] To produce the two-layer molded article by the powder
molding, for example, a mold whose molding surface may be provided
with a complicated pattern is heated to a temperature higher than
the melt temperature of the thermoplastic elastomer composition,
and then the above described powder or the pellet of thermoplastic
powder is fed on the molding surface of the mold, and the powder or
the pellet is molten and adhered each other to obtain a sheet-like
melt on the molding surface. After the unadhered excess powder or
pellet is removed, powder or pellet of the thermoplastic polymer
composition containing a foaming agent are fed on this sheet-like
melt and the powder is adhered and molten each other to obtain a
sheet-like melt on the molding surface. Then, the unadhered excess
powder or pellet is removed, followed by heating and foaming to
form a foamed layer.
[0082] It is also possible to form a composite molded article
composed of an unfoamed layer, a foamed layer and an unformed layer
by the powder molding method. In this case, unfoamed layers may be
the same or different. Examples of the foaming agent include the
same thermal decomposition type foaming agents as those described
above. Examples of the polymer component in the thermoplastic
polymer composition containing the foaming agent include a vinyl
chloride resin, a polyolefin resin, an olefin thermoplastic
elastomer and the like. It is also possible to use a foamable
polyethylene composition disclosed as a thermoplastic polymer
composition containing the foaming agent in JP-A-07-228720.
[0083] As the foamed layer, a polyurethane foam can also be used.
In this case, since it tends to be inferior in adhesion between the
thermoplastic elastomer composition of the present invention and
polyurethane, the adhesion can be improved by pre-treating the
surface of the molded article to be adhered, with a primer such as
chlorinated polyethylene or the like.
[0084] The polyurethane foamed layer can be molded by fixing the
above molded article and a core material described hereinafter to
the predetermined position with providing a constant distance,
pouring a previously mixed liquor of a polyol and a polyisocyanate,
followed by foaming under pressure.
[0085] The molded article or two-layer molded article is suitable
as a skin material to be laminated on a thermoplastic resin core
material. For example, the above molded article can be used as a
material for producing a multi-layer molded article by laminating
the thermoplastic resin core material on one surface thereof. The
two-layer molded article can be used as a material for producing a
multi-layer molded article by laminating the thermoplastic resin
core material on the foamed layer thereof.
[0086] As the thermoplastic resin core material, for example, there
can be used polyolefin resins such as polypropylene, polystyrene
and the like; and thermoplastic resins such as ABS resin
(acrylonitrile-butadiene-styre- ne copolymer) and the like. Among
them, polyolefin resins such as polypropylene are preferably
used.
[0087] The multi-layer molded article can be easily produced, for
example, by a method of feeding a thermoplastic resin melt on one
surface of the molded article, followed by pressing, or a method of
feeding a thermoplastic resin melt on the foamed layer side of the
two-layer molded article, followed by press molding.
[0088] The thermoplastic resin melt means a thermoplastic resin in
the molten state by heating to a temperature higher than its melt
temperature. The thermoplastic resin melt may be fed before or on
pressing. The pressing may be performed by using a mold, or
performed by a feeding force of the thermoplastic resin melt.
Examples of the molding method include an injection molding method,
a low-pressure injection molding method, a low-pressure compression
molding method and the like.
[0089] For example, in case of using the above molded article as a
skin material, the molded article is fed between a pair of opened
molds, and then both molds may be clamped after or while feeding a
thermoplastic resin melt between one surface of the molded article
and one mold which is opposite to the surface. In case of using a
two-layer molded article as the skin material, the two-layer molded
article is fed between a pair of opened molds, and then both molds
may be clamped after or while feeding a thermoplastic resin melt
between the foamed layer of the molded article and one mold which
is opposite to the foamed layer. The opening/closing direction of
both molds is not specifically limited, and may be a vertical
direction or a horizontal direction.
[0090] When using the molded article or two-layer molded article
produced by using the above mold for powder molding as a skin
material, the mold for powder molding method can be used as one
mold in the production of the above multi-layer molded article
while holding the molded article or two-layer molded article on the
molded surface. According to this method, since the molded article
or two-layer molded article to which a pattern of the mold is
transferred is fed between the molds without being separated from
the molds, a desired multi-layer molded article can be obtained
without damaging the pattern provided on the surface.
[0091] The thermoplastic resin melt can be fed after the completion
of the clamping, but both molds are preferably clamped while or
after feeding when both molds are not closed, because there can be
obtained a multi-layer molded article wherein the molded article or
two-layer molded article scarcely shifts and a transfer degree of
the pattern is improved. The method of feeding the thermoplastic
resin melt is not specifically limited, and the thermoplastic resin
melt can be fed through a resin passage provided in one mold which
is opposite to the molded article or two-layer molded article. A
feeding nozzle of the molten resin is inserted between both molds
and the molten resin is fed, and then the feeding nozzle may be
removed out of the system to close both molds.
[0092] As a pair of molds, there can be used a pair of male/female
molds wherein the outer periphery of the first mold member and
inner periphery of the second mold member are capable of sliding.
In this case, by setting a clearance in sliding surface between
molds to almost the same value as that of a thickness of the molded
article or two-layer molded article, a multi-layer molded article
having an excess skin material at the edge portion can be obtained.
A multi-layer molded article whose edge portion is coated with the
skin material can be produced by turning up this excess skin
material to the back surface of the multi-layer molded article.
[0093] The thermoplastic elastomer composition of the present
invention scarcely causes whitening on bending, and can provide a
molded article having an excellent flexibility.
EXAMPLES
[0094] The present invention will be illustrated by the following
Examples, but is not limit thereto.
[0095] The thermoplastic elastomer composition and molded article
were evaluated as follows:
[0096] (1) Complex Dynamic Viscosity .eta.*(1) and Newtonian
Viscosity Index n
[0097] A storage rigidity G'(.omega.) and a loss rigidity
G"(.omega.) are measured at a vibration frequency .omega. of 1
radian/sec. or 100 radian/sec. by using a dynamic spectrometer
(RDS-7700 manufactured by Rheometrix Inc.), and then .eta.*(1) and
.eta.*(100) are calculated by the above described calculation
formula (1). The measurement is conducted at an applied strain of
5% and a sample temperature of 25.degree. C. in a parallel plate
mode.
[0098] The Newtonian viscosity index n is determined by the above
described calculation formula (2) using .eta.*(1) and
.eta.*(100).
[0099] (2) Proportion of the Number of Hydrogenated Conjugated
Diene Units Having a Side Chain with at Least Two Carbon Atoms to
the Total Number of Hydrogenated Conjugated Diene Units in the
Hydrogenated Conjugated Diene Copolymer Rubber
[0100] It is determined by .sup.1H-NMR measurement (400 MHz) using
a o-xylene-d10 solution of hydrogenated conjugated diene copolymer
rubber the at the concentration of 1.6 mg/ml.
[0101] (3) Sphere-Reduced Average Diameter
[0102] An average volume per one particle is calculated from the
total weight of arbitrarily selected 100 particles and a specific
gravity. Then, a diameter of a sphere having the same volume as
that average volume is calculated, and used as a sphere-reduced
average diameter.
[0103] (4) Bulk Specific Gravity
[0104] 100 ml of powder or pellet of thermoplastic elastomer
composition is collected and weighed, and a bulk specific gravity
is calculated according to JIS K-6721.
[0105] (5) Flexibility of Molded Article
[0106] After cutting the molded article into pieces of 1 cm.times.5
cm, ten pieces are piled and a Shore A-scale hardness of the
resulting laminate is determined according to JIS K-6301.
[0107] [6] Whitening on Bending
[0108] The molded article was cut into pieces of 1 cm.times.5 cm
and bent by applying a bending load of 500 g or 1 kg for a minute.
After removing the load, the evaluation is conducted on the basis
of the width of the portion whitened on bending according to the
following criteria:
[0109] 1: Width of the whitened portion is 2 mm or more.
[0110] 2: Width of the whitened portion is 1 mm or more and less
than 2 mm.
[0111] 3: Width of the whitened portion is less than 1 mm.
[0112] 4. No whitened portion is recognized.
[0113] (7) Solid Viscoelasticity
[0114] Using a solid viscoelasticity measuring apparatus (SDM 5600H
manufactured by Seiko Instrument Inc.), DS200 (tension mode) is
employed. A sample of 1 cm.times.10 cm.times.1 mm in thickness is
made by a press molding and the measurement is conducted by
vibrating the sample within the range from -150 to 130.degree. C.
at a heating rate of 2.degree. C./min., a vibration frequency of 10
Hz and a vibration amplitude of 25 .mu.m to determine a peak
temperature and an intensity of a tan .delta. peak.
[0115] (8) Appearance of Molded Article
[0116] In the powder slush molded article, presence of pinholes or
wormholes at each edge of three protrusions A (7 mm in
height.times.25 mm in width), B (11 mm in height.times.25 mm in
width) and C (15 mm in height.times.25 mm in width) shown in FIG. 1
is observed by naked eyes, and the results were evaluated according
to the following criteria.
[0117] 1: Pinhole and underfill are found at the edges of the
protrusions A, B and C.
[0118] 2: Neither pinhole nor underfill is found at the edges of
the protrusion A, but pinholes and underfill are found at the edges
of the protrusions B and C.
[0119] 3: Neither pinhole nor underfill is found at the edges of
the protrusions A and B, but pinholes and underfill are found at
the edges of the protrusion C.
[0120] 4: Neither pinhole nor underfill is found at the edges of
the protrusions A, B and C.
Reference Example 1
[0121] To EPDM (propylene unit content=28% by weight, iodine
value=12) of 100 parts by weight, 100 parts by weight of a mineral
oil base softener (DIANA PROCESS (trademark) PW-380 manufactured by
Idemitsu Kosan Co., Ltd.) was added to obtain an oil-extended EPDM.
50 parts by weight of the oil-extended EPDM and 50 parts by weight
of an ethylene-propylene random copolymer resin (peak temperature
of tan .delta. peak=-2.degree. C., intensity=0.2, ethylene unit
content=5% by weight, MFR=90 g/10 min.) and 0.4 part by weight of a
bismaleimide compound as a crosslinking aid (SUMIFINE (trademark)
BM manufactured by Sumitomo Chemical Co., Ltd.) were melt-kneaded
using a Banbury mixer for 10 minutes and then formed into granule
using an extruder to obtain a master batch.
[0122] To the master batch (100 parts by weight), 0.1 parts by
weight of 2,5-dimethyl-2,5-di(t-butylperoxyno)hexane as an organic
peroxide (SUNPEROX (trademark) APO manufactured by Sanken Kako Co.,
Ltd.) was added and kneaded in a twin-screw extruder (TEX-44,
manufactured by Nippon Steel Works, Ltd.) at 220.degree. C. to
effect dynamic crosslinking to obtain a thermoplastic elastomer
composition, which had .eta.*(1) of 5.2.times.10.sup.3 poise and n
of 0.31. The thermoplastic elastomer composition was cut by a
cutter to obtain granule.
[0123] EPDM in this composition had a peak temperature (of tan
.delta. peak) of -45.degree. C. and an intensity of 0.12.
Example 1
[0124] The granule (100 parts by weight) obtained in Reference
Example 1 and, as a hydrogenated conjugated diene copolymer rubber,
a hydrogenated butadiene-styrene copolymer (styrene unit
content=10% by weight, hydrogenation rate=99%,
.eta.*(1)=8.3.times.10.sup.3 poise, n=0.16, MFR=10 g/10 min.,
proportion of hydrogenated conjugated diene units having a side
chain of at least two carbon atoms to hydrogenated total conjugated
diene units=71%, peak temperature of tan .delta. peak=-22.degree.
C., intensity=1.5) (20 parts by weight) were kneaded and molten
with a 40 mm .phi. extruder at 180.degree. C. to obtain a
thermoplastic elastomer composition, which was cut by a cutter to
obtain granule.
[0125] This granule was cooled to -120.degree. C. by using liquid
nitrogen and then pulverized while maintaining a cooled state to
obtain a powder passing through a Tyler standard sieve of 32 mesh
(opening of 500 .mu.m.times.500 .mu.m), of the thermoplastic
elastomer composition.
[0126] The resulting powder (1000 g) of the thermoplastic elastomer
composition was fed on the molding surface of a
nickel-electroplated mold (30 cm.times.30 cm.times.3 mm in
thickness. Previously heated to 250.degree. C. (surface
temperature) for fourteen seconds, unadhered excess powder was
dropped off from the mold. Thereafter, the resultant was heated in
an oven at 250.degree. C. for 60 seconds, cooled and then released
from the mold to obtain a sheet-like molded article having a
thickness of 1 mm. The evaluation results of the thermoplastic
elastomer composition and molded article are shown in Table 1.
Example 2 and Comparative Example 1
[0127] In the same manner as in Example 1 except for using the
hydrogenated conjugated diene copolymer rubber in the amount
described in Table 1, a thermoplastic elastomer composition was
obtained, and then a molded article was obtained. The evaluation
results of the thermoplastic elastomer composition and molded
article are shown in Table 1.
Comparative Example 2
[0128] In the same manner as in Example 1 except for using an
ethylene-propylene copolymer rubber [SPO V0141 manufactured by
Sumitomo Chemical Co., Ltd., propylene unit content=27% by weight,
.eta.*(1)=5.2.times.10.sup.4 poise, n=0.2] (20 parts by weight) in
place of the hydrogenated conjugated diene copolymer rubber, a
thermoplastic elastomer composition was obtained, and then a molded
article was obtained. The evaluation results of the thermoplastic
elastomer composition and molded article are shown in Table 1.
Reference Example 2
[0129] A propylene-ethylene copolymer resin [ethylene unit
content=4.5% by weight, MFR=228 g/10 min., peak temperature of tan
.delta. peak=-2.degree. C., intensity=0.2] (66.7 parts by weight)
and an ethylene-propylene copolymer rubber [SPO V0141 manufactured
by Sumitomo Chemical Co., Ltd., propylene unit content=27% by
weight, MFR=1 g/10 min.] (33.3 parts by weight) were kneaded in a
twin-screw extruder at a shear rate of 1.2.times.10.sup.3
sec.sup.-1 and at 200.degree. C. to obtain a composition
[.eta.*(1)=3.0.times.10.sup.3 poise, n=0.12], which was cut by a
cutter to obtain granule.
[0130] The ethylene-propylene copolymer rubber in this composition
had a peak temperature (of tan .delta. peak) of -45.degree. C. and
an intensity of 0.12.
Example 3
[0131] In the same manner as in Example 1 except for using granule
(100 parts by weight) obtained in Reference Example 2 in place of
the granule of the composition obtained in Reference Example 1 and
changing the amount of the hydrogenated conjugated diene copolymer
rubber to 66.7 parts by weight, a thermoplastic elastomer
composition was obtained, and then a molded article was obtained.
The evaluation results of the thermoplastic elastomer composition
and molded article are shown in Table 1.
Example 4
[0132] A propylene-ethylene random copolymer resin [ethylene unit
content=4.5% by weight, MFR=228 g/10 min., peak temperature of tan
.delta. peak=-2.degree. C., peak intensity=0.2] (100 parts by
weight), as a hydrogenated conjugated diene copolymer rubber, a
hydrogenated butadiene-styrene copolymer (styrene unit content=10%
by weight, hydrogenation rate=99%, complex dynamic viscosity
.eta.*(1)=8.3.times.10.- sup.3 poise, Newtonian viscosity index
n=0.16, MFR=10 g/10 min., proportion of hydrogenated conjugated
diene units having a side chain of at least two carbon atoms to
hydrogenated total conjugated diene units=71%, peak temperature of
tan .delta. peak=-22.degree. C., peak intensity=1.5) (10 parts by
weight), and an ethylene-hexene copolymer rubber (Engage 8400,
hexene content=25% by weight, MFR=30 g/10 min., manufactured by Dow
Chemical Co., Ltd.) (90 parts by weight) were kneaded in a twin
screw extruder at a temperature of 200.degree. C., at a share rate
of 1.2.times.10.sup.3 sec.sup.-1 to obtain a composition (complex
dynamic viscosity .eta.*(1)=9.times.10.sup.2 poise, n=0.12). The
extruded strand was cut by a cutter to obtain thermoplastic
elastomer composition granule. Then, powder of the composition was
obtained, and a molded article was obtained in the same manner as
in Example 1.
[0133] Evaluation results of the thermoplastic elastomer
composition and the molded article are shown in Table 2.
Example 5
[0134] A propylene-ethylene random copolymer resin [ethylene unit
content=4.5% by weight, MFR=228 g/10 min., peak temperature of tan
.delta. peak=-2.degree. C., peak intensity=0.2] (100 parts by
weight), as a hydrogenated conjugated diene copolymer rubber, a
hydrogenated butadiene-styrene copolymer (styrene unit content=15%
by weight, hydrogenation rate=95%, complex dynamic viscosity
.eta.*(1)=6.times.10.su- p.3 poise, n=0.02, MFR=65 g/10 min.,
proportion of hydrogenated conjugated diene units having a side
chain of at least two carbon atoms to hydrogenated total conjugated
diene units=60%, peak temperature of tan .delta. peak=-11.degree.
C., peak intensity=1.8) (100 parts by weight), and an
ethylene-propylene copolymer rubber [SPO V0141 manufactured by
Sumitomo Chemical Co., Ltd., propylene unit content=27% by weight,
MFR=1 g/10 min.] (50 parts by weight) were kneaded in a twin-screw
extruder at a temperature of 200.degree. C., at a share rate of
1.2.times.10.sup.3 sec.sup.-1 to obtain a composition
(.eta.*(1)=9.times.10.sup.2 poise, n=0.03). The extruded strand was
cut by a cutter to obtain thermoplastic elastomer composition
granule.
[0135] Then, powder of the composition was obtained, and a molded
article was obtained in the same manner as in Example 1.
[0136] Evaluation results of the thermoplastic elastomer
composition and the molded article are shown in Table 1.
Comparative Example 3
[0137] In the same manner as in Example 3 except for using no
hydrogenated conjugated diene copolymer rubber, a thermoplastic
elastomer composition was obtained, and then a molded article was
obtained. The evaluation results of the thermoplastic elastomer
composition and molded article are shown in Table 1.
Comparative Example 4
[0138] In the same manner as in Example 3 except for using an
ethylene-propylene random copolymer rubber [SPO V0141 manufactured
by Sumitomo Chemical Co., Ltd., propylene unit content=27% by
weight, .eta.*(1)=5.2.times.10.sup.4 poise, n=0.2] (66.7 parts by
weight) in place of the hydrogenated conjugated diene copolymer
rubber, a thermoplastic elastomer composition was obtained, and
then a molded article was obtained. The evaluation results of the
thermoplastic elastomer composition and molded article are shown in
Table 1.
Comparative Example 5
[0139] A propylene-ethylene random copolymer resin [ethylene unit
content=4.5% by weight, MFR=228 g/10 min., peak temperature of tan
.delta. peak=-2.degree. C., peak intensity=0.2] (100 parts by
weight), as a hydrogenated conjugated diene copolymer rubber, a
hydrogenated butadiene-styrene copolymer (styrene unit content=10%
by weight, hydrogenation rate=99%, complex dynamic viscosity
.eta.*(1)=8.3.times.10.- sup.3 poise, Newtonian viscosity index
n=0.16, MFR=10 g/10 min., proportion of hydrogenated conjugated
diene units having a side chain of at least two carbon atoms to
hydrogenated total conjugated diene units=71%, peak temperature of
tan .delta. peak=-22.degree. C., peak intensity=1.5) (4 parts by
weight), and an ethylene-hexene copolymer rubber (Engage 8400,
hexene content=25% by weight, MFR=30 g/10 min., manufactured by Dow
Chemical Co. Ltd.) (96 parts by weight) were kneaded in a
twin-screw extruder at a temperature of 200.degree. C., at a share
rate of 1.2.times.10.sup.3 sec.sup.-1 to obtain a composition
(complex dynamic viscosity .eta.*(1)=7.times.10.sup.2 poise,
n=0.02). The extruded strand was cut by a cutter to obtain
thermoplastic elastomer composition granule. Then, powder of the
composition was obtained, and a molded article was obtained in the
same manner as in Example 1.
[0140] Evaluation results of the thermoplastic elastomer
composition and the molded article are shown in Table 2.
1 TABLE 1 Polyolefin Tan .delta. peak resin HCR** EAC** Peak
Whitening on (Part by (Part by (Part by .eta.*(1) temp. Peak
bending weight) weight) weight) (poise) n (.degree. C.) intensity
Flexibility 500 g 1000 g Example 1 100 40.2 101*** 2.0 .times.
10.sup.3 0.13 -27 0.2 86 4 4 Example 2 100 80.4 101*** 3.6 .times.
10.sup.3 0.13 -35 0.32 82 4 4 Comparative 100 0 101*** 5.2 .times.
10.sup.3 0.31 92 2 2 Example 1 Comparative 100 0 141*** 2.6 .times.
10.sup.4 0.38 88 1 1 Example 2 Example 3 100 100 50 2.7 .times.
10.sup.3 0.13 -17 1.1 86 4 4 Example 4 100 10 90 7.0 .times.
10.sup.2 0.02 -5 0.15 90 4 3 Example 5 100 100 50 9.0 .times.
10.sup.2 0.03 -5 0.36 86 4 4 Comparative 100 0 50 3.0 .times.
10.sup.3 0.12 92 2 1 Example 3 Comparative 100 0 150 6.7 .times.
10.sup.3 0.09 87 1 1 Example 4 Comparative 100 4 96 7.0 .times.
10.sup.2 0.02 -5 0.14 90 2 2 Example 5 Notes: **HCR: Hydrogenated
conjugated diene based copolymer rubber, **EAC: Ethylene
.alpha.-olefin copolymer rubber ***Total amount of EAC includes the
amount of crosslinking agent and crosslinking aid (Examples
1.about.4).
Example 6
[0141] (Production of Thermoplastic Elastomer Composition
Pellets)
[0142] A propylene-ethylene random copolymer resin [ethylene unit
content=4.5% by weight, MFR=228 g/10 min., peak temperature of tan
.delta. peak=-2.degree. C., peak intensity=0.2] (100 parts by
weight) and as a hydrogenated conjugated diene copolymer rubber, a
hydrogenated butadiene-styrene polymer (styrene unit content=10% by
weight, hydrogenation rate=99%, complex dynamic viscosity
.eta.*(1)=8.3.times.10.- sup.3 poise, Newtonian viscosity index
n=0.16, MFR=10 g/10 min., proportion of hydrogenated conjugated
diene units having a side chain of at least two carbon atoms to
hydrogenated total conjugated diene units=71%, peak temperature of
tan .delta. peak=-22.degree. C., peak intensity=1.5) (100 parts by
weight) were fed in a 30 mm .phi. extruder, kneaded at 160.degree.
C. The molten mixture was extruded from a die
(temperature=160.degree. C.) having a discharge opening with a
diameter of 1.0 mm at a discharge rate of 1 kg/hour/opening, and
then an extruded strand was drawn at a haul-off rate of 32 m/min.
and cooled to obtain a strand having a diameter of 0.8 mm. The
strand was cut to obtain thermoplastic elastomer composition pellet
having a sphere-reduced average diameter of 0.91 mm and a bulk
specific gravity of 0.47 (complex dynamic viscosity
.eta.*(1)=2.0.times.10.sup.3 poise, Newtonian viscosity index
n=0.05, peak temperature of new tan .delta. peak=-17.degree. C.,
intensity=1.1).
[0143] (Production of Molded Article by Slush Molding)
[0144] The resulting thermoplastic elastomer composition pellet 3
was charged into a container 2, and then the container 2 and a mold
1 for slush molding were integrated with mating peripheries of
their openings closely (FIG. 1).
[0145] The mold 1 had three depressed portions having depths of 7
mm, 11 mm and 15 mm, respectively, and a width of 25 mm each, and
all molding surfaces had leather grain decorations. The mold was
heated to 250.degree. C.
[0146] Then, the integrated container 2 and mold 1 were rotated by
180.degree. using an uniaxial rotator to supply the pellet 3 onto
the molding surface of the mold 1 and further reciprocated at an
amplitude of .+-.45.degree. over 15 seconds for two rounds to
adhere the pellets to the molding surfaces of the mold 1. After
stopping the reciprocation, the integrated container 2 and the mold
were rotated by 180.degree. to the original position, whereby the
pellet was recharged into the container 2.
[0147] Thereafter, the mold 1 was detached from the container 2 and
heated in an oven at 250.degree. C. for 2 minutes, followed by
cooling. Then, the molded article was released from the mold.
[0148] This molded article 5 had a thickness of 1.2 mm, and three
protrusions with heights of 7 mm, 11 mm and 15 mm, respectively,
and a width of 25 mm each. On the surface of the article, the
leather grain decoration was exactly transferred.
[0149] Evaluation results of the thermoplastic elastomer
composition, the pellet and the molded article are shown in Table
2.
Comparative Example 6
[0150] To 25 parts by weight of EPDM (propylene unit content=28% by
weight, iodine value=12), 25 parts by weight of a mineral oil base
softener (DIANA PROCESS (trademark) PW-380 manufactured by Idemitsu
Kosan Co., Ltd.) was added to obtain an oil-extended EPDM. The
oil-extended EPDM and a propylene-ethylene random copolymer resin
(ethylene unit content=4.5% by weight, MFR=90 g/10 min., peak
temperature of tan .delta.=-2.degree. C., peak intensity=0.2) (50
parts by weight) and a bismaleimide compound as a crosslinking aid
(SUMIFINE (trademark) BM manufactured by Sumitomo Chemical Co.,
Ltd.) (0.6 part by weight) were kneaded by a Banbury mixer for 10
minutes to obtain a master batch for crosslinking. To the master
batch (100 parts by weight),
2,3-dimethyl-2,5-di(t-butylperoxyno)hexane as an organic peroxide
(SUNPEROX (trademark) APO manufactured by Sanken Kako Co., Ltd.)
(0.4 part by weight) was added and kneaded in a twin-screw extruder
at a shear rate of 1.2.times.10.sup.3 sec.sup.-1 and 200.degree. C.
to effect dynamic crosslinking to obtain a thermoplastic elastomer
composition (complex dynamic viscosity .eta.*(1)=1.5.times.10.sup.3
poise, Newtonian viscosity index n=0.25). The thermoplastic
elastomer composition was extruded from the twin-screw extruder and
cut by a cutter to obtain granule.
[0151] This thermoplastic elastomer composition was charged in a 30
mm .phi. extruder and then molten. The molten thermoplastic
elastomer was extruded from a die (temperature=160.degree. C.)
having discharge openings with a diameter of 1.0 mm at a discharge
rate of 1 kg/hour/opening, and then an extruded strand was drawn at
a haul-off rate of 32 m/min. and cooled to obtain a strand having a
diameter of 0.8 mm. The strand was cut by a pelletizer to obtain
thermoplastic elastomer composition pellet having a sphere-reduced
average particle diameter of 0.91 mm and a bulk specific gravity of
0.47.
[0152] In the same manner as in Example 6 except for using the
above obtained thermoplastic elastomer composition powder in place
of the thermoplastic elastomer composition powder obtained in
Example 6, a molded article was obtained.
[0153] Evaluation results of the thermoplastic elastomer
composition, the pellet and the molded article are shown in Table
2.
Comparative Example 7
[0154] The thermoplastic elastomer composition obtained in
Comparative Example 6 was cooled to -100.degree. C. using liquid
nitrogen and immediately ground in a cooled state to obtain a
thermoplastic elastomer composition powder (sphere-reduced average
particle diameter=0.20 mm, bulk specific gravity=0.29) which passed
a Tyler standard sieve of 32 mesh (opening of 500 .mu.m.times.500
.mu.m). In the same manner in Example 6 except for using this
thermoplastic elastomer composition pellet, a molded article was
obtained.
[0155] Evaluation results of the thermoplastic elastomer
composition and the molded article are shown in Table 2.
Reference Example 3
[0156] To EPDM (ML.sub.1+4(100.degree. C.)=242, propylene unit
content=28% by weight, iodine value=12) (25 parts by weight), the
same weight of a mineral oil base softener (DIANA PROCESS
(trademark) PW-380 manufactured by Idemitsu Kosan Co., Ltd.) was
added to obtain an oil-extended EPDM (ML.sub.1+4(100.degree.
C.)=53). The oil-extended EPDM and a propylene-ethylene random
copolymer resin (ethylene unit content=4.5% by weight, MFR=90 g/10
min., peak temperature of tan .delta.=-2.degree. C., peak
intensity=0.2) (50 parts by weight) and a bismaleimide compound as
a crosslinking aid (SUMIFINE (trademark) BM manufactured by
Sumitomo Chemical Co. Ltd.) (0.6 parts by weight) were kneaded by a
Banbury mixer for 10 minutes to obtain a master batch for
crosslinking.
[0157] To the master batch for crosslinking (100 parts by weight),
2,3-dimethyl-2,5-di(t-butylperoxyno)hexane as an organic peroxide
(SUNPEROX (trademark) APO manufactured by Sanken Kako Co., Ltd.)
(0.4 parts by weight) was added and kneaded in a twin-screw
extruder at a shear rate of 1.2.times.10.sup.3 sec.sup.-1 and
200.degree. C. to effect dynamic crosslinking to obtain a
thermoplastic elastomer composition (complex dynamic viscosity
.eta.*(1)=1.5.times.10.sup.3 poise, Newtonian viscosity index
n=0.25).
Example 7
[0158] 100 parts by weight of the crosslinked thermoplastic
elastomer obtained in Reference Example 3 and, as a hydrogenated
conjugated diene copolymer rubber and 20 parts by weight of a
hydrogenated butadiene-styrene polymer (styrene unit content=10% by
weight, hydrogenation rate=99%, complex dynamic viscosity
.eta.*(1)=8.3.times.10.- sup.3 poise, Newtonian viscosity index
n=0.16, MFR=10 g/10 min., proportion of hydrogenated conjugated
diene units having a side chain of at least two carbon atoms to
hydrogenated total conjugated diene units=71%, peak temperature of
tan .delta. peak=-22.degree. C., peak intensity=1.5) were charged
in a 30 mm .phi. extruder, and kneaded at 160.degree. C. The molten
mixture was extruded from a die (temperature=160.degree. C.) having
a discharge opening with a diameter of 1.0 mm at a discharge rate
of 1 kg/hour/opening, and then an extruded strand was drawn at a
haul-off rate of 32 m/min. and cooled to obtain a strand having a
diameter of 0.8 mm. The strand was cut by a pelletizer to obtain
thermoplastic elastomer composition pellet having a sphere-reduced
average diameter of 0.90 mm and a bulk specific gravity of 0.47
[complex dynamic viscosity .eta.*(1)=1.0.times.10.sup.3 poise,
Newtonian viscosity index n=0.15, peak temperature of new tan
.delta. peak=-17.degree. C., intensity=1.5]. In the same manner as
in Example 6 except for using this thermoplastic elastomer
composition pellet, a molded article was obtained.
[0159] Evaluation results of the thermoplastic elastomer
composition, the pellet and the molded article are shown in Table
2.
Reference Example 4
[0160] 66.7 parts by weight of a propylene-ethylene random
copolymer resin (ethylene unit content=4.5% by weight, NMR=228 g/10
min.) and 33.3 parts by weight of an ethylene-propylene random
copolymer rubber (ESPRENE V0141 manufactured by Sumitomo Chemical
Co., Ltd., propylene unit content=27% by weight, MFR=1 g/10 min.)
were kneaded in a twin-screw extruder at a shear rate of
1.2.times.10.sup.3 sec.sup.-1 and 200.degree. C. to obtain a
composition (complex dynamic viscosity .eta.*(1)=3.0.times.10.sup.3
poise, Newtonian viscosity coefficient n: 0.12).
Example 8
[0161] 100 parts by weight of the thermoplastic elastomer obtained
in Reference Example 3 and 66.7 parts by weight of, as a
hydrogenated conjugated diene copolymer rubber, a hydrogenated
butadiene-styrene polymer (styrene unit content=10% by weight,
hydrogenation rate=99%, complex dynamic viscosity
.eta.*(1)=8.3.times.10.sup.3 poise, Newtonian viscosity index
n=0.16, MFR=10 g/10 min., proportion of hydrogenated conjugated
diene units having a side chain of at least two carbon atoms to
hydrogenated total conjugated diene units=71%, peak temperature of
tan .delta. peak=-22.degree. C., peak intensity=1.5) were charged
in a 30 mm .phi. extruder, and kneaded at 160.degree. C. The
resulting molten mixture was extruded from a die
(temperature=160.degree. C.) having a discharge opening with a
diameter of 1.0 mm at a discharge rate of 0.8 kg/hour/opening, and
then an extruded strand was drawn at a haul-off rate of 35 m/min.
and cooled to obtain a strand having a diameter of 0.8 mm. The
strand was cut by a pelletizer to obtain thermoplastic elastomer
composition pellet having a sphere-reduced average particle
diameter of 0.8 mm and a bulk specific gravity of 0.46 [complex
dynamic viscosity .eta.*(1)=2.7.times.10.sup.3 poise, Newtonian
viscosity index n=0.13, peak temperature of new tan .delta.
peak=-17.degree. C., intensity=1.1]. In the same manner as in
Example 6 except for using this thermoplastic elastomer composition
pellet, a molded article was obtained.
[0162] Evaluation results of the thermoplastic elastomer
composition, the pellet and the molded article are shown in Table
2.
Example 9
[0163] A propylene-ethylene random copolymer resin [ethylene unit
content=4.5% by weight, MFR=228 g/10 min., peak temperature of tan
.delta. peak=-2.degree. C., peak intensity=0.2] (100 parts by
weight), as a hydrogenated conjugated diene copolymer rubber, a
hydrogenated butadiene-styrene copolymer (styrene unit content=10%
by weight, hydrogenation rate=99%, complex dynamic viscosity
.eta.*(1)=8.3.times.10.- sup.3 poise, Newtonian viscosity index
n=0.16, MFR=10 g/10 min., proportion of hydrogenated conjugated
diene units having a side chain of at least two carbon atoms to
hydrogenated total conjugated diene units=71%, peak temperature of
tan .delta. peak=-22.degree. C., peak intensity=1.5) (10 parts by
weight), and an ethylene-hexene copolymer rubber (Engage 8400,
hexene content=25% by weight, MFR=30 g/10 min., manufactured by Dow
Chemical Co., Ltd.) (90 parts by weight) were kneaded in a twin
screw extruder at a temperature of 200.degree. C., at a share rate
of 1.2.times.10.sup.3 sec.sup.-1 to obtain a composition (complex
dynamic viscosity .eta.*(1)=7.times.10.sup.2 poise, n=0.02), then
the composition was formed into pellet, and thereafter, a molded
article was obtained in the same manner as in Example 6 except that
this composition was used.
[0164] Evaluation results of the thermoplastic elastomer
composition, the pellet and the molded article are shown in Table
2.
Example 10
[0165] A propylene-ethylene random copolymer resin [ethylene unit
content=4.5% by weight, MFR=228 g/10 min., peak temperature of tan
.delta. peak=-2.degree. C., peak intensity=0.2] (100 parts by
weight), as a hydrogenated conjugated diene copolymer rubber, a
hydrogenated butadiene-isoprene-styrene copolymer (styrene unit
content=15% by weight, hydrogenation rate=95%, complex dynamic
viscosity .eta.*(1)=6.times.10.su- p.2 poise, Newtonian viscosity
index n=0.02, MFR=65 g/10 min., proportion of hydrogenated
conjugated diene units having a side chain of at least two carbon
atoms to hydrogenated total conjugated diene units=60%, peak
temperature of tan .delta. peak=-11.degree. C., peak intensity=1.8)
(100 parts by weight), and an ethylene-propylene copolymer rubber
[SPO V0141 manufactured by Sumitomo Chemical Co., Ltd., propylene
unit content=27% by weight, MFR=1 g/10 min.] (50 parts by weight)
were kneaded in a twin screw extruder at a temperature of
200.degree. C., at a share rate of 1.2.times.10.sup.3 sec.sup.-1 to
obtain a composition (complex dynamic viscosity
.eta.*(1)=9.times.10.sup.2 poise, n=0.03). Then, pellet of the
composition was obtained, and a molded article was obtained in the
same manner as in Example 1.
[0166] Evaluation results of the thermoplastic elastomer
composition, the pellet and the molded article are shown in Table
2.
Comparative Example 8
[0167] A propylene-ethylene random copolymer resin [ethylene unit
content=4.5% by weight, MFR=228 g/10 min., peak temperature of tan
.delta. peak=-2.degree. C., peak intensity=0.2] (100 parts by
weight), as a hydrogenated conjugated diene copolymer rubber, a
hydrogenated butadiene-styrene copolymer (styrene unit content=10%
by weight, hydrogenation rate=99%, complex dynamic viscosity
.eta.*(1)=8.3.times.10.- sup.3 poise, Newtonian viscosity index
n=0.16, MFR=10 g/10 min., proportion of hydrogenated conjugated
diene units having a side chain of at least two carbon atoms to
hydrogenated total conjugated diene units=71%, peak temperature of
tan .delta. peak=-22.degree. C., peak intensity=1.5) (4 parts by
weight), and an ethylene-hexene copolymer rubber (Engage 8400,
hexene content=25% by weight, MFR=30 g/10 min., manufactured by Dow
Chemical Co., Ltd.) (96 parts by weight, were kneaded in a twin
screw extruder at a temperature of 200.degree. C., at a share rate
of 1.2.times.10.sup.3 sec.sup.-1 to obtain a composition (complex
dynamic viscosity .eta.*(1)=7.times.10.sup.2 poise, n=0.02), then
the composition was formed into pellet, and thereafter, a molded
article was obtained in the same manner as in Example 6 except that
this composition was used.
[0168] Evaluation results of the thermoplastic elastomer
composition, the pellet and the molded article are shown in Table
2.
2 TABLE 2 Sphere- Appear- Polyolefin Tan .delta. peak reduced ance
resin HCR** EAC** Peak Peak average bulk Whitening of (Part by
(Part by (Part by .eta.*(1). temp. inten- particle specific Flexi-
on bending molded weight) weight) weight) (poise) n (.degree. C.)
sity size gravity bility 500 g 1000 g article Example 6 100 100 0
2.0 .times. 10 0.05 -17 1.1 0.91 0.47 88 4 4 4 Comparative 100 0
101*** 1.5 .times. 10.sup.3 0.25 0.91 0.47 92 2 2 4 Example 6
Comparative 100 0 101*** 1.5 .times. 10.sup.3 0.25 0.20 0.29 92 2 2
2 Example 7 Example 7 100 40.2 101*** 1.0 .times. 10.sup.3 0.15 -17
1.5 0.90 0.47 88 4 4 4 Example 8 100 100 50 2.7 .times. 10.sup.3
0.13 -17 1.1 0.80 0.46 86 4 4 4 Example 9 100 100 50 9.0 .times.
10.sup.2 0.03 -5 0.36 0.80 0.45 86 4 4 4 Example 10 100 10 90 7.0
.times. 10.sup.2 0.02 -5 0.15 0.85 0.46 90 4 3 4 Comparative 100 4
96 7.0 .times. 10.sup.2 0.02 -5 0.14 0.85 0.46 90 3 2 4 Example 8
Notes: **HCR: Hydrogenated conjugated diene based copolymer rubber,
**EAC: Ethylene .alpha.-olefin copolymer rubber ***Total amount of
EAC includes the amount of crosslinking agent and crosslinking aid
(Comparative Example 6.about.7, Examples 7).
* * * * *