The present invention relies to a medical tube comprising a propylene polymer composition.
FIELD OF THE INVENTION
The present invention relates to a propylene polymer composition, and more particularly to a propylene polymer composition having excellent transparency, flexibility, scratch resistance, heat resistance and rubber elasticity-. The invention also relates to a flexible medical tube made from the composition that is suitable for transporting medical fluids such as blood and infusion solutions.
BACKGROUND OF THE INVENTION
Polypropylenes include isotactic poiypropylenes and . syndiotactic polypropylenes. The isotactic polypropylenes give films that are inexpensive and possess high transparency, toughness, humidity resistance and heat resistance. Such films are therefore widely used as packaging materials . Of the isotactic polypropylene films, ethylene/propylene random copolymer films are particularly excellent in transparency but reduce the transparency and flexibility with increasing film thickness. For example, the film thickness is up to about 60 µm in order to obtain sufficient transparency such that the
packaging material does not deteriorate the appearance of
content. Accordingly, production of thick polypropylene
films high in transparency and flexibility has .been difficult.
On the other hand, the syndiotactic polypropylenes are
known to be obtained by low temperature polymerization in the
presence of a catalyst that includes a vanadium compound, an
ether and an organoaluminum. The polymers obtained by this
method, however, possess low syndiotacticity and cannot
exhibit the inherent syndiotactic properties.
In this connection, J. A. Ewen et al. were the first to
find that high-tacticity polypropylenes having a syndiotactic
pentad ratio of above 0.7 can be obtained by polymerization
in the presence of a catalyst containing a transition metal
catalyst with asymmetric ligands and .an aluminoxane (J. Am.
Chem. Soc., 1988, 110, 6255-6256).
The polymers obtained.by the method of J. A. Ewen et al.
have high syndiotacticity and are more elastic than the
isotactic polypropylenes. However, such flexible forming
materials cannot satisfy the flexibility, rubber elasticity
and mechanical strength as required in the field where soft
vinyl chloride and vulcanized rubbers are used.
Attempts have been widely made to improve the
polypropylene's flexibility and impact resistance by
incorporating an ethylene/propylene copolymer rubber or the
like. Articles from the resin compositions obtained by this
method show a certain level of flexibility and impact
resistance, but the rubber elasticity and mechanical strength
thereof are insufficient.
Medical tubes include tubes for introducing or deriving
L.
a substance into or from a body, and catheters inserted into
the body for test or treatment. Specific examples of the
medical tubes include catheters such as urinary catheters,
stomach catheters and suction catheters, tubes such as
infusion solution tubes, enteral feeding tubes, peritoneal
dialysis tubes, blood transfusion tubes and tubes connected
to a urinary catheter to guide urine to a urine collection bag,
circuit tubes used in blood circuits for hemodialysis,
artificial heart lungs and plasmapheresis,- and tubes for
transporting substances in the medical field. The
transporting tubes for medical substances include tubes
attached to multiple blood bags and tubes connecting an
aspirator and a catheter. Many of the conventional medical
tubes are made from polyvinyl chloride that is inexpensive and
possesses excellent kink resistance and a certain level of
flexibility (pliancy). However, alternative materials have
been required out of consideration to the environment and the
like.
The alternatives studied so far include styrene
elastomer compositions (JP-A-2000-63577, JP-A-2001-252348
and JP-A-2001-1432) , thermoplastic polyurethane compositions
(JP-A-H05-84293), and syndiotactic I,2-polybutadiene
compositions (JP-A-2000-334038 and JP-A-2001-104473) . The
fact, however, is that these compositions have low-versatility
and practical utility due to insufficient flexibility and high
costs.
To achieve the versatility and practical utility,
studies have been made on copolymers of ethylene and a-olef ins
of 3 or more carbon atoms, and acid copolymers of ethylene and
vinyl acetate. However, none has satisfied performances
required such as flexibility, heat resistance and kink
resistance.
Of the polypropylenes such as the isotactic
polypropylenes and syndiotactic polypropylenes, the isotactic
polypropylenes are inexpensive and excellent in transparency
and heat resistance, and are therefore widely used in various
packaging materials and industrial materials. However, their
flexibility is unsatisfactory. To solve this problem,
compositions have been studied in which a flexible material
such as an ethylenic elastomer is blended with polypropylene.
However, none has satisfied performances as required.
DISCLOSURE OF THE INVENTION
The present invention has been made to solve the above
problems in the art. It is therefore an object of the invention
to provide a propylene polymer composition well balanced and
excellent in transparency, flexibility, heat resistance,
scratch resistance and rubber elasticity.
• Further, the present inventors made intensive studies
of medical tubes excellent in heat resistance, flexibility and
kink resistance that are capable of solving the problems in
the art, and have arrived at a medical tube having well balanced
properties that is obtained from a specific propylene polymer
composition.
Apropylene polymer composition according to the present
invention satisfies all the following properties (A) , (B) , (C)
and (D) :
(A) the composition shows a loss tangent (tan5) peak at
a temperature in the range of -20 to 25°C according to dynamic
viscoelasticity measurement (10 rad/s) in a torsion mode, and
the peak value is 0.5 or above;
.(B) the storage elastic modulus G' at 20°C from the
dynamic viscoelasticity measurement is in the range of 1.0-xlO7
to 4.9xl08 dyn/cm2;
(C) the penetration temperature (°C) determined in
accordance with JIS K 7196 is in the range of 60 to 160°C; and
(D) the composition has a permanent set of not more than
30% as determined after the composition fixed between chucks
30 mm apart is 100% strained at a stress rate of 30 mm/min,
maintained for 10 minutes and released for 10 minutes.
The propylene polymer composition comprises:
(i) 1 to 40 parts by weight-of a syndiotactic
polypropylene; and
(ii) 60 to 99 parts by weight of a syndiotactic
propylene/ethylene copolymer that contains 99 to 55 mol% of
a syndiotactic propylene component and 1 to 45 mol% of an
ethylene component (the total of the syndiotactic
polypropylene (i) and the syndiotactic propylene/ethylene
copolymer (ii) is 100 parts by weight);
wherein the composition has a Young's modulus (YM) of
not more than 100 MPa as- determined in accordance with JIS 6301.
A medical tube according to the present invention
comprises the above propylene polymer composition.
In a preferred embodiment, the syndiotactic
polypropylene (i) has a 13C-NMR syndiotactic pentad ratio
(rrrr) of 0.5 or above, and a melt flow index (MFI) in the range
of 0.1 to 50 g/10 min; and the copolymer (ii) has an intrinsic
viscosity [r\] of 0.01-to 10 dl/g as determined at 135°C in
decalin, a GPC molecular weight distribution of not more than
4, and a glass transition temperature Tg of not more than -10°C.
The propylene polymer composition has well-balanced and
excellent transparency, flexibility, heat resistance, scratch
resistance and rubber elasticity.
The propylene polymer composition and the medical tube
made from the propylene polymer composition are excellent in
the balance of transparency,, flexibility, heat resistance,
scratch resistance and rubber elasticity, and possess superior
kink resistance that has been a problem in the art.
BRIEF DESCRIPTION OF THE DRAWING
Fig. 1 shows an evaluation jig used in the present
invention. The evaluation jig is a hollow cylinder (1) having
a hole 10 mm in diameter and 5 mm in height. A tube (2). having
an inner diameter of 2.1 mm and a length of 20 cm is looped
by inserting both ends thereof into the jig, and the ends are
slowly pulled down until a kink occurs in the loop. The loop
length (H) at the occurrence of kink is obtained as indicator
of the kink resistance. The shorter the loop length, the
higher the kink resistance.
PREFERRED EMBODIMENTS OF THE INVENTION
Hereinbelow, the propylene polymer composition of the
invention will be described in detail.
Propylene polymer composition
The propylene polymer composition according to the
present invention satisfies all the following properties (A) ,
(B) , (C) and (D) :
(A) the composition shows a loss tangent (tan6) peak at
a temperature in the range of -20 to 25°C according to dynamic
viscoelasticity measurement (10 rad/s) in a torsion mode, and
the peak value is 0.5 or above;
(B) the storage elastic modulus G' at 20°C from the
dynamic viscpelasticity measurement is in the range of l.OxlO7
to 4.9xl08 dyn/cm2;
(C) the penetration temperature (°C) determined in
accordance with JIS K 7196 is in the range of 60 to 160°C; and
(D) the composition has a permanent set of not more than
30% as determined after the composition fixed between chucks
30 mm apart is 100% strained at a stress rate of 30 mm/min,
maintained for 10 minutes and released for 10 minutes.
In the property (A) , the loss tangent (tanS) at -20 to
25°C is 0.5 or above, preferably in the range of 0.5 to 2.5,
and more preferably in the range of 0.6 to 2. When the loss
tangent (tanS) at -20 to 25°C is lower than 0.5, the composition
tends to show insufficient flexibility or, even if having
flexibility, tends to be poor in scratch resistance.
In the property (B) , the storage elastic modulus G' at
20°C is in the range of l.OxlO7 to 4.9xl08 dyn/cm2, preferably
in the range of S.OxlO"7 to 4.9xl08 dyn/cm2, and more preferably
in the range of S.OxlO"7 to 4.9xl08 dyn/cm2.
When the storage elastic modulus G' at 20°C is less than
l.OxlO7, the surface stickiness tends to occur to deteriorate
handling properties. When the storage elastic modulus G'
exceeds 4.9xl08, the product having a large thickness tends
to show insufficient flexibility and lower strain recovery
from a folded state.
In the property (C) , the penetration temperature (°C)
determined in accordance with JIS K 7196 is in the range of
60 to 160°C, preferably in the range of 60 to 150°C, and more
preferably in the range of 80 to 140°C. When the penetration
temperature is below 60°C, the composition cannot be applied
to uses requiring heating and sterilization.
In the property (D) , the permanent set is not more than
30%, preferably not more than 25%, and still preferably not
more than 20% as determined after' a dumbbell specimen 50 mm
in length, 15 mm in gauge length, 5 mm in width and 1 mmt in
thickness that is fixed between chucks 30 mm apart is 100%
strained at a stress rate of 30 mm/min, maintained for 10
minutes and released for 10 minutes. 'When the permanent set
exceeds 30%, the rubber elasticity tends to be low, and the
composition cannot be applied to uses requiring stretching
properties and recovery properties.
The propylene polymer composition of the invention does
10
not contain any of ethylene/a-olef in block copolymers (a) and
aromatic hydrocarbon block copolymers (b).
Ethylene/a-olefin block copolymers (a)
The ethylene/ot-olefin block copolymers (a) that are not
contained in the propylene polymer composition are composed
of a low crystalline copolymeric segment and an amorphous
copolymeric segment wherein the low crystalline copolymeric
segment contains a crystalline polyethylene segment that
includes 5 to 40 mol% of a structural unit derived from an olef in
of 3 to 10 carbon atoms and 60 to 95 mol% of a structural unit
derived from ethylene.
The ethylene/a-olef in block copolymers satisfy all the
conditions 1 to 3:
1. The melting point (Tm) obtained from a DSC endothermic
curve and the ethylene content (C2) determined by common NMR
have a relation of: Tm (°C) > 3.9 x C2 (mol%).- 230.
2. The molecular weight distribution by GPC is in the
range of 1 to 1.5.
3. The component soluble in n-decane at room temperature
constitutes 0 to 20 wt%.
The content of the 23°C n-decane soluble component in
the ethylene/a-olef in block copolymers is measured as follows .
A 1-liter flask equipped with a stirrer is charged with 3 g
of a polymer sample, 20 mg of 2, 6-di-tert-butyl-4-methylphenol
and 500 ml of n-decane, and is heated on a 145°C oil bath to
dissolve the polymer sample. After the polymer sample has been
dissolved, the solution is cooled to room temperature over a
period of about 8 hours and is held on a 23°C water bath for
8 hours-. The polymer precipitated is filtered out from the
n-decane solution containing the dissolved polymer by means
of a G-4 (or G-2) glass filter. The solution is then heated
at 10 mmHg-and 150°C to perform drying until a fixed amount
is reached of the polymer dissolved in the n-decane solution.
The weight is obtained as the content of the 23°C n-decane
soluble component. The content of the 23°C n-decane soluble
component in the ethylene/a-olefin block copolymer is
expressed in percentage relative to the weight of the polymer
sample.
The olefins of 3 to 20 carbon atoms include propylene,
1-butene, 1-pentene, 1-hexene, 4-methyl-l-pentene,
3-methyl-l-pentene, 1-octene, 3-methyl-l-butene, 1-decene,
1-dodecene, 1-tetradodecene, 1-hexadecene, 1-octadecene,
1-eicosene, cyclopentene, cycloheptene, norbornene,
5-ethyl-2-norbornene, tetracyclododecene and
2-ethyl-l,4,5,8-dimethano-l,2, 3, 4,4a,5,8,8aoctahydronaphthalene.
The copolymers may contain two or more kinds of the
structural units derived from the C3-20 olefins or ethylene.
The ethylene/a-olefin block copolymers may contain up
to 5 mol% of a structural unit derived from a diene compound
of 4 to 20 carbon atoms.
The diene compounds include 1,3-butadiene,
lf3-pentadiene, 1,4-pentadiene, 1,3-hexadiene, 1, 4-hexadiene
I,5-hexadiene, 4-methyl-l, 4-hexadiene,
5-methyl-l,4-hexadiene, 6-methyl-l,6-octadiene,
7-methyl-l,6-octadiene, 6-ethyl-l,6-octadiene,
6-propyl-l,6-octadiene, 6-butyl-l,6-octadiene,
6-methyl-l,6-nonadiene, 7-methyl-l,6-nonadiene,
6-ethyl-l,6-nonadiene, 7-ethyl-l,6-nonadiene,
6-methyl-l,6-decadiene, 7-methyl-l,6-decadiene,
6-methyl-l,6-undecadiene, 1,7-octadiene, 1, 9-decadiene,
isoprene, butadiene, ethylidenenorbornene, vinylnorbornene
and dicyclopentadiene.
Production of the ethylene/a-olefin.block copolymers
(a) is disclosed in, for example, JP-A-H05-043770.
Aromatic hydrocarbon block copolymers (b)
The aromatic hydrocarbon block copolymers (b) that are
not contained in the propylene polymer composition include
aromatic vinyl/conjugated diene block copolymers (bl) having
a block polymer unit (X) derived from an aromatic vinyl and
a block polymer unit (Y) derived from a conjugated diene, and
hydrogenated products thereof (b2).
The aromatic vinyl/conjugated diene block copolymers
(bl) of the above structure are for example indicated by X (YX) n
or (XY)n (where n is an integer of 1 or greater).
In the styrene block copolymers, the aromatic vinyl block
polymer units (X), which are hard segments, are present as
crosslinking points for the conjugated diene block polymer
units (Y) to form a physically crosslinked structure (domain) .
The conjugated diene block polymer units (Y) present among the
aromatic vinyl block polymer units (X) are soft segments and
have rubber elasticity.
The aromatic vinyls for the block polymer units (X)
include styrene and styrene derivatives such as
a-methylstyrene, 3-methylstyrene, p-methylstyrene,
4-propylstyrene, 4-dodecylstyrene, 4-cyclohexylstyrene,
2-ethyl-4-benzylstyrene and 4-(phenylbutyl)styrene. The
conjugated dienes for the block polymer units (Y) include
butadiene, isoprene, pentadiene, 2,3-dimethylbutadiene and
combinations thereof. When the conj ugated diene block polymer
units (Y) are derived from butadiene and isoprene, the
isoprene- and butadiene-derived units are contained in an
amount of 40 mol% or more. The .conjugated diene block polymer
unit (Y) may be any of a random copolymer unit, a block copolymer
unit and a tapered copolymer unit. The content of the aromatic
vinyl polymer units may be determined by a common method such
as infrared spectroscopy or NMR spectroscopy. The
hydrogenated products (b2) of aromatic vinyl/conjugated diene
block copolymers- may be- obtained by hydrogenating the above
aromatic vinyl/conjugated diene block copolymers (bl) by a
common method. The hydrogenated products (b2) of the aromatic
vinyl/conjugated diene block copolymers generally have a
hydrogenation ratio of 90% or above. The hydrogenation ratio
is a value relative to the total content (100%) of carbon-carbon
double bonds -in the conjugated diene block polymer units (Y) .
The hydrogenated products (b2) of the aromatic
vinyl/conjugated diene block copolymers include hydrogenated
styrene/isoprene block copolymer (SEP), hydrogenated
styrene/isoprene/styrene block copolymer (SEPS;
polystyrene/polyethylene/propylene/polystyrene block
copolymer) and hydrogenated styrene/butadiene block copolymer
(SEES; pol'ystyrene/polyethylene/butylene/polystyrene block
copolymer). Specific examples include products commercially
available under the trade names of HYBRAR (manufactured by
KURARAY CO., LTD.), KRATON (manufactured by SHELL CHEMICALS
LIMITED), CALIFLEX TR (manufactured by SHELL CHEMICALS
LIMITED), SOLPRENE (manufactured by Phillips Petroleum
Company), EUROPRENE SOLT (manufactured by ANIC), TUFPRENE
(manufactured by Asahi Kasei Chemicals Corporation),
SOLPRENE-T (manufactured by JAPAN ELASTOMER CO. , LTD. ) JSR-TR
(manufactured by JSR CORPORATION) , DENKA STR (manufactured by
DENKI KAGAKU KOGYO KABUSHIKI KAISHA) , QUINTAC (manufactured
by ZEON CORPORATION) , KRATON G (manufactured by SHELL
CHEMICALS LIMITED) and TUFTEC (manufactured by Asahi Kasei
Chemicals Corporation).
The propylene polymer composition having the aforesaid
properties (A) to (D) preferably contains a propylene polymer
(i) and a syndiotactic prppylene/ethylene copolymer (ii).' The
propylene polymer (i) is an isotactic polypropylene or a
syndiotactic polypropylene, and is preferably a syndiotactic
polypropylene. The propylene polymer composition contains
the propylene polymer (i) in an amount of 1 to 40 parts by weight,
and preferably 5 to 30 parts by weight, and the syndiotactic
propylene/ethylene copolymer (ii) in an amount of 60 to 99 parts
by weight, and preferably 70 to 95 parts by weight. The
syndiotactic propylene/ethylene copolymer (ii) preferably has
a propylene content of 99 to 55 mol%, more preferably 95 to
60 mol%, and still preferably 90 to 70 mol%. The
stereoregularity of the ot-olefin segment may be atactic,
isotactic or syndiotactic without limitation, and is
preferably syndiotactic. The a-olefin content and
stereoregularity can be known by common NMR. In a particularly
preferred embodiment, the propylene polymer composition is a
syndiotactic propylene polymer composition as described
below.
Syndiotactic propylene polymer composition
The propylene polymer composition of the invention
preferably comprises:
(i) 1 to 40 parts by weight of a syndiotactic
polypropylene; and
(ii) 60 to 99 parts by weight of a syndiotactic
propylene/ethylene copolymer that contains 99 to 55 mol% of
a syndiotactic propylene component and 1 to 45 mol% of an
ethylene component (the total of the syndiotactic
polypropylene (i) and the syndiotactic propylene/ethylene
copolymer (ii) is 100 parts by weight);
wherein the composition has a Young's modulus (YM) of
not more than 100 MPa as determined in accordance with JIS 6301.
The propylene polymer composition may further contain
a terpene resin or petroleum resin, or a hydrogenated
derivative thereof (iii) that has a weight-average molecular
weight (Mw) of 500 to 10000. In the above case, the propylene
polymer composition contains:
(i) 1 to 40 parts by weight of a syndiotactic
polypropylene;
(ii) 59 to 98 parts by weight of a syndiotactic
propylene/ethylene copolymer that contains 99 to 55 mol% of
a syndiotactic propylene component and 1 to 45 mol% of an
ethylene component; and
(iii) 1 to 30 parts by weight of a terpene. resin or
petroleum resin, or a hydrogenated derivative thereof that has
a'weight-average molecular weight (Mw) of 500 to 10000; and
the composition has a Young's modulus (YM) of not more than
100 MPa as determined in accordance with JIS 6301.
The components (i) and (ii) contained in the propylene
polymer composition -will be discussed below.
(i) Syndiotactic polypropylene
The syndiotactic polypropylene (i) may contain a small
amount of copolymerized units derived from ethylene or an
a-olefin of 4 or more carbon atoms, in an amount of not more
than 20 wt%, and preferably not more than 15 wt%.
The syndiotactic polypropylene can be prepared by using
a catalyst, for example a metallocene catalyst disclosed in
JP-A-H02-41303.
The syndiotactic pentad ratio (rrrr, pentad
syndiotacticity) is 0.5 or above, preferably 0 . 6 or above, more
preferably 0.7 or above, and particularly preferably 0.80 or
above. The syndiotactic polypropylene with a syndiotactic
pentad ratio of 0.5 or above is excellent in heat resistance
and forming properties, and shows good characteristics as
crystalline polypropylene.
The syndiotactic pentad ratio (rrrr) is obtained from
the formula (1):
rrrr fraction = Prrrr/PW (1)
wherein Prrrr is an absorption intensity in a 13C-NMR spectrum
assigned to the methyl group of the third unit in five
sequential syndiotactic propylene units, and Pw is the total
of absorption intensities in a 13C-NMR spectrum assigned to
all the methyl groups of the propylene units.
NMR measurement is carried out as follows: 0..35 g of
a sample is dissolved in 2.0 ml of hexachlorobutadiene by
heating. The solution is filtered through a glass filter (G2)
and 0.5 ml of deuterated benzene is added to the filtrate. The
mixture is placed in an NMR tube having an inner diameter of
10 mm, and 13C-NMR measurement is carried out at 120°C using
NMR apparatus GX-500 manufactured by JEOL. The measurement
is performed 10,000 scans or more.
The melt flow index (MFI,, 190°C, 2.16 kg load) of the
syndiotactic polypropylene is desirably 0.1 to 50 g/10 min,
preferably 0.1 to 30 g/10 min, and more preferably 0.1 to
g/10 min.. When MFI is in the above range, the syndiotactic
polypropylene tends to show good flowability and be easily
miscible with other components. Further, the composition
obtained will give formed products having high mechanical
strength.
The density of the syndiotactic polypropylene is
desirably 0.86 to 0.91 g/cm3, and preferably 0.865 to 0.90 g/cm3.
The syndiotactic polypropylene having this density tends to
exhibit good forming properties and give formed products with
sufficient flexibility.
(ii) Syndiotactic propylene/ethylene copolymer
The syndiotactic propylene/ethylene copolymer contains
a syndiotactic propylene component in an amount of 99 to 55
mol%, preferably 95 to 60 mol%, and particularly preferably
90 to 65 mol%, and an ethylene component in an amount of 1 to
45 mol%, preferably 5 to 40 mol%, and particularly preferably
10 to 35 mol%. Containing the ethylene and propylene
components in the above amounts, the syndiotactic
propylene/ethylene copolymer (ii) tends to show good
compatibility with the syndiotactic polypropylene . Further,
the propylene polymer composition obtained will exhibit
adequate transparency, flexibility, heat resistance and
scratch resistance.
The intrinsic viscosity [r|] of the syndiotactic
propylene/ethylene copolymer (ii) is desirably in the range
of 0.01 to 10 dl/g, and preferably 0.05 to 10 dl/g as determined
at 135°C in decalin. The syndiotactic propylene/ethylene
copolymer (ii) having this intrinsic viscosity [r\] will show
superior characteristics such as weather resistance, ozone
resistance, thermal aging resistance, low- temperature
properties and dynamic fatigue resistance.
The syndiotactic propylene/ethylene' copolyruer (ii)
desirably has a single glass transition temperature, and the
glass transition temperature Tg is desirably -10°C or less,
and preferably -15°C or less as measured with a differential
scanning calorimeter (DSC). The syndiotactic
propylene/ethylene copolymer (ii) having the above glass
transition temperature Tg has excellent cold resistance and
low temperature properties.
The GPC molecular weight distribution (Mw/Mn in terms
of polystyrene, Mw: weight-average molecular weight, Mn:
number-average molecular weight) is preferably 4.0 or less.
The 13C-NMR spectrum of the syndiotactic
propylene/ethylene copolymer recorded using a
1,2,4-trichloroberizene solution shows a peak near 20.2 ppm
that has a relative intensity ratio of 0.3 or above, preferably
0 . 5 or above, and particularly preferably 0 . 6 or above relative
to the peak intensities assigned to all the methyl groups of
the propylene units. When the ratio is 0.3 or above, excellent
transparency, scratch resistance and impact resistance can be
achieved.
The syndiotactic structure can be determined as follows:
0 . 35 g of a sample is dissolved in 2 . 0 ml of hexachlorobutadiene
by heating. The solution is filtered through a glass filter
(G2) and 0. 5 ml of deuterated benzene is added to the filtrate .
The mixture is placed in an NMR tube having an inner diameter
of 10 mm, and 13C-NMR measurement is carried out at 120°C using
NMR apparatus GX-500 manufactured by JEOL. The measurement
is performed 10,000 scans or more.
Production of syndiotactic propylene/ethylene copolymer (.ii)
The syndiotactic propylene/ethylene copolymer (ii) can
be produced using the same metallocene catalyst as used for
preparation of the syndiotactic polypropylene (i) or a
catalyst described in Japanese Patent Application No.
2002-332243, although not limited thereto.
Terpene resin, petroleum resin or hydrogenated derivative
thereof (iii)
The terpene resin or petroleum resin, or the^hydrogenated
derivative thereof (iii) desirably has a weight-average
molecular weight of 500 to 10000, preferably 500 to 7000, and
more preferably 500 to 5000, and a glass transition temperature
(Tg) obtained from a DSC endothermic curve in the range of
to 100°C, preferably 40 to 100°C, and more preferably 50 to
100°C.
The terpene resin or petroleum resin, or the hydrogenated
derivative thereof having the above characteristics shows high
resistance to heat and discoloration, and enables the
composition to exhibit high transparency, scratch resistance
22
and stress relaxation properties.
A formed product of the propylene polymer composition
desirably has a degree of cloudiness (haze) of not more than
25%, and preferably not more than 20% as measured in accordance
with ASTM D 1003.
The formed product, of the propylene polymer composition
desirably has a Young's modulus (YM) of not more than 100 MPa,
and preferably not more than 80 MPa as determined in accordance
with JIS 6301.
The propylene polymer composition of the invention
generally has a melt flow rate (ASTM D 1238, 230°C, 2.16 kg
load) of 0.0001 to 1000 g/10 min, preferably O.OOOl to 900 g/10
min, and more preferably 0.0001 to 800 g/10 min, and an
intrinsic viscosity [t|] of 0.01 to 10 dl/g, preferably 0.05
to 10 dl/g, and more preferably 0.1 to 10 dl/g as determined
at 135°C in decahydronaphthalene.
The melt tension (MT) of the propylene polymer
composition is generally in the range of 0.5 to 10 g, and
preferably 1 to 10 g, leading to excellent forming properties
into films and tubes. The melt tension (MT) is a tension
applied to a filament (strand) when the filament being extruded
at 200°C and an extrusion speed of 15 mm/min is withdrawn at
a constant rate (10 m/min) , and is measured with a melt tension
tester (manufactured by Toyo Seiki Seisaku-Sho, Ltd.).
Production of propylene polymer composition
To produce the propylene polymer composition, the
aforementioned components can be mixed in the specified
amounts by a number of known processes, for example by mixing
by means of a Henschel mixer, a V-type blender, a ribbon blender
or a Tumbler mixer, or by mixing as above and melt-kneading
the mixture with a single screw extruder, a twin screw extruder,
a kneader or a Banbury mixer, followed by granulating or
pulverizing..
The propylene polymer composition may contain additives
as required while still achieving the objects of the invention.
Examples of the additives include weathering stabilizers, heat
stabilizers, antistatic agents, anti-slip agents,
anti-blocking agents, anti-fogging agents, lubricants,
pigments, dyes, plasticizers, anti-aging agents, hydrochloric
acid absorbers and antioxidants. Further, "other copolymers"
(elastomers) described hereinbelow may be used without
departing from the scope of the invention and while still
achieving the objects of the invention.
Other copolymers
The propylene polymer composition may contain "other
polymers" (elastomers or elastomer resins) as required.
Examples of the "other copolymers" include
ethylene/a-olefin random copolymers (A), ethylene/diene
copolymers (E) and ethylene/triene copolymers (F) . These
copolymers may be used singly or in combination of two or more
kinds.
The "other copolymer" may be used in an amount of 0 to
30 parts by weight per 100 parts by weight of the syndiotactic
polypropylene polymer. Addition of the "other copolymer" in
the above amount enables the composition to give formed
products having an excellent balance in flexibility,
transparency and low temperature impact resistance.
Ethylene/a-olefin random copolymers (A)
Preferred ethylene/cc-olefin random copolymers (A) for
use in the invention are soft ethylene/a-olefin copolymers
having a density of 0.860 to less than 0.895 g/cm3, preferably
0.860 to 0.890 g/cm3, and a melt flow rate (MFR; ASTM D 1238,
190°C, 2.16 kg load) of 0.5 to 30 g/10 min, preferably 1 to
20 g/10 min.
The cc-olefins to be copolymerized with ethylene include
those of 3 to 20 carbon atoms, such as propylene, 1-butene,
1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene,
1-undecene, 1-dodecene, 1-hexadodecene, 1-octadecene,
1-nonadecene, 1-eicosene and 4-methyl-1-pentene. Of these,
the a-olefins of 3 to 10 carbon atoms are preferred. The
a-olefins may be used singly or in combination of two or more
kinds.
The ethylene/a-olefin random copolymers (A) desirably
contain 60 to 90 mol% of a unit derived from ethylene and 10
to 40 mol% of a unit derived from the C3-20 a-olefin.
The ethylene/a-olefin random copolymers (A) may further
contain a unit derived from other polymerizable monomer while
still achieving the objects of the invention.
Examples of such polymerizable monomers include vinyl
compounds such as styrene, vinylcyclopentene,
vinylcyclohexane and vinylnorbornane; vinyl esters such as
vinyl acetate; unsaturated organic acids such as maleic
anhydride and derivatives of the unsaturated organic acids;
conjugated dienes such as butadiene, isoprene, pentadiene and
2,3-dimethylbutadiene; and non-conjugated polyenes such as
1,4-hexadiene, 1,6-octadiene, 2-methyl-l,5-hexadiene,
6-methyl-l,5-heptadiene, 7-methyl-l,6-octadiene,
dicyclopentadiene, cyclohexadiene, dicyclooctadiene,
methylenenorbornene, 5-vinylnorbornene,
5-ethylidene-2-norbornene, 5-methylene-2-horbornene,
5-isopropylidene-2-norbornene,
6-chloromethyl-5-isopropenyl-2-norbornene,
2, 3-diisopropylidene-5-norbornene,
2-ethylidene-3-isopropylidene-5-norbornene and
2-propenyl-2,2-norbornadiene.
The ethylene/a-olefin random copolymers (A) may contain
the unit derived from the above polymerizable monomer in an
amount of 10 mol%' or less, preferably 5 mol% or less, and more
preferably 3 mol% or less.
Specific examples of the ethylene/a-olefin random
copolymers (A) include ethylene/propylene random copolymer,
ethylene/1-butene random copolymer,
ethylene/propylene/1-butene random copolymer,
ethylene/propylene/ethylidenenorbornene random copolymer,
ethylene/1-hexene random copolymer and ethylene/1-octene
random copolymer. Of these, the ethylene/propylene random
copolymer, ethylene/1-butene random copolymer,
ethylene/1-hexene random copolymer and ethylene/1-octene
random copolymer are particularly preferable. These
copolymers may be used in combination of two or more kinds.
The ethylene/a-olef in random copolymers (A) used in the
invention generally have a degree of crystallinity of not more
than 40%, preferably in the range of 0 to'39%, and more
preferably 0 to 35% according to X ray diffractometry.
The ethylene/a-olef in random copolymers may be produced
by known methods using vanadium catalysts, titanium catalysts
or metallocene catalysts.
The ethylene/a-olefin random copolymer (A) may be
contained in the propylene polymer composition in an amount
of 0 to 40 wt%, and preferably 0 to 35 wt%. Containing the
ethylene/a-olefin random copolymer (A) in this amount, the
composition can give formed products having an excellent
balance in toughness, hardness, transparency and impact
resistance.
Ethylene/diene copolymers (E)
The ethylene/diene copolymers (E) used as elastomers in
the invention are random copolymers of ethylene and dienes.
The dienes to be copolymerized with ethylene include
non-conjugated dienes such as dicyclopentadiene,
1,4-hexadiene, cyclooctadiene, methylenenorbornene and
ethylidenenorbornene; and conjugated dienes such as butadiene
and isoprene. Of these, butadiene and isoprene are preferred.
These dienes may be used singly or in combination of two or
more kinds.
The ethylene/diene copolymers (E) desirably contain a
diene-derived structural unit in an amount of 0.1 to 30 mol%,
preferably 0.1 to 20 mol%, and more preferably 0.5 to 15 mol%.
The iodine value thereof is desirably in the range of 1 to 150,
preferably 1 to 100, and more preferably 1 to 50. The
ethylene/diene copolymers (E) desirably have an intrinsic
viscosity [r\] of 0.01 to 10 dl/g, preferably 0.05 to 10 dl/g,
and more preferably 0.1 to 10 dl/g as determined at 135°C in
decahydronaphthalene. The ethylene/diene copolymers (E) can
be produced by known methods.
The ethylene/diene copolymer (E) may be contained in the
propylene polymer composition in an amount of 0 to 40 wt%, and
preferably 0 to 35 wt%. Containing the ethylene/diene
copolymer (E) in this amount, the composition can give formed
products having an excellent balance in toughness, hardness,
transparency and impact resistance.
Ethylene/triene copolymers (F)
The ethylene/triene copolymers (F) used as elastomers
in the invention are random copolymers of ethylene and trienes.
The trienes to be copolymerized with ethylene include
non-conjugated trienes such as
6,10-dimethyl-l,5,9-undecatriene,
4,8-dimethyl-l,4,8-decatriene,
5,9-dimethyl-l,4,8-decatriene,
6,9-dimethyl-l,5,8-decatriene,
6,8,9-trimethyl-l,5,8-decatriene,
6-ethyl-10-methyl-l,5,9-undecatriene,
4-ethylidene-l,6-octadiene,
7-methyl-4-ethylidene-l,6-octadiene,
4-ethylidene-8-methyl-l,7-nonadiene (EMND),
7-methyl-4-ethylidene-l,6-nonadiene,
7-ethyl-4-ethylidene-l,6-nonadiene,
6,7-dimethyl-4-ethylidene-l, 6-octadiene,
6,7-dimethyl-4-ethylidene-l, 6-nonadiene,
4-ethylidene-l,6-decadIene,
7-methyl-4-ethylidene-l, 6-decadiene,
7-methyl-6-propyl-4-ethylidene-l,6-octadiene,
4-ethylidene-l,7-nonadiene,
8-methyl-4-ethylidene-l, 7-nonadiene and.
4-ethylidene-l,7-undecadiene; and conjugated trienes such as
1,3,5-hexatriene. These trienes may be used singly or in
combination of two or more kinds.
The trienes may be produced by known methods as disclosed
in EP 0691354 Al and WO 96/20150.
The ethylene/triene copolymers (F) desirably contain a
triene-derived structural unit in an amount of 0.1 to 30 mol%,
preferably 0.1 to 20 mol%, and more preferably 0.5 to 15 mol%.
The iodine value thereof is desirably in the-range of 1 to 200,
preferably 1 to 100, and more preferably 1 to 50.
The ethylene/triene copolymers (F) desirably have an
intrinsic viscosity [TI] of 0.01 to 10 dl/g, preferably 0.05
to 10 dl/g, and more preferably 0.1 to 10 dl/g as determined
at 135°C in decahydronaphthalene.
The ethylene/triene copolymers (F) can be produced by
known methods. The ethylene/triene copolymer (F) may be
•contained in'the propylene polymer composition in an amount
of 0 to 40 wt%, and preferably 0 to 35 wt%. Containing the
ethylene/triene copolymer (F) in this amount, the composition
can give formed products having an excellent balance in
toughness, hardness, transparency and impact resistance.
Formed products
The propylene polymer composition of the present
invention can be used widely in conventional applications of
polyolefins. In particular, the polyolefin composition can
be formed into products of various shapes such as sheets,
unoriented or oriented films and filaments.
Examples of the formed products include those
manufactured by known thermoforming processes such as
extrusion, injection molding, blown-film extrusion, blow
molding, extrusion blow molding, injection blow molding, press
molding, vacuum forming, calendering and foam molding.
Several.examples will be presented below to describe the formed
products.
Extruded products according to the present invention are
not particularly limited in shape and product variety, and
examples thereof include sheets, (unoriented) films, pipes,
hoses, wire coatings and tubes, with sheets (skin materials)
films and tubes being preferred.
Extrusion of the propylene polymer composition can
employ a common extruder and extrusion conditions. For
example, the propylene polymer composition can be molten in
a single screw extruder, a kneading extruder, a ram extruder
or a gear extruder and be extruded through a predetermined die
into a desired shape.
Injection molded products can be manufactured by
injection molding the propylene polymer composition into
various shapes under known conditions using a common injection
molding apparatus. The injection molded products of the
propylene polymer composition of the invention are antistatic
and excellent in transparency, flexibility, heat resistance,
impact resistance, surface gloss, chemical resistance and
abrasion resistance to find wide applications in automobile
interior trim materials, automobile exterior materials and
containers.
Blow molded products can be made by blow molding the
propylene polymer composition under known conditions using a
common blow molding apparatus. For example, extrusion blow
molding produces a hollow product by a series of steps in which
the propylene polymer composition in a molten state at a resin
temperature of 100 to 300°C is extruded through a die to form
a tubular parison, the parison is fixed in a mold of a desired
shape, and air is blown to fit the parison into the mold at
a resin temperature of 130 to 300°C. The draw (blowing) ratio
is desirably about 1.5 to 5 times in the lateral direction.
Injection blow molding produces a hollow product by a
series of steps in which the propylene polymer composition is
injected at a resin-temperature of 100 to 300°C into a parison
mold to form a parison, the parison is fixed in a mold of a
desired shape, and air, is blown to fit the parison into the
mold at a resin temperature of 120 to 300°C. The draw (blowing)
ratio is desirably 1.1 to 1.8 times in the longitudinal
direction and 1.3 to 2.5 times in the lateral direction. The
blow molded products of the propylene polymer composition
possess high transparency, flexibility, heat resistance and
impact resistance and have superior moisture proofness.
Press molded products include those by mold stamping.
For example, such products are produced by press molding a
substrate and a skin material simultaneously to integrate them
(mold stamping forming) in which the propylene polymer
composition constitutes the substrate.
The mold stamping formed products include automobile
interior materials such as door trims, rear package trims, seat
back garnishes and instrument panels.
Medical tubes of the propylene polymer composition can
be. manufactured using a common extruder and under known
extrusion conditions. For example, the propylene polymer
composition can be molten in a single screw extruder, a kneading
extruder, a ram extruder -or a gear extruder and be extruded
through a circular die, followed by cooling.
The medical tubes may have a laminated structure
according to need such as prevention of adsorption of chemicals
to the inner surface or impartment of heat resistance, without
impairment of the medical tube performance.
According to the present invention, there can be obtained
the propylene polymer composition capable of giving formed
products well balanced and excellent in transparency, impact
resistance, flexibility, heat resistance, scratch resistance
and rubber elasticity.
The medical tubes of the propylene polymer composition
according to the present .invention have well balanced
properties such as transparency, kink resistance, flexibility,
heat resistance, scratch resistance and rubber elasticity, and
adequately satisfy the performance expected as medical tubes.
EXAMPLES
The present invention will be hereinafter described in
greater detail by Examples, but it should be construed that
the invention is in no way limited to those Examples.
The conditions for testing properties are as follows.
[Evaluation of kink resistance]
The evaluation employed a jig that was a hollow cylinder
(1) having a hole 10 mm in diameter and 5 mm in height. A tube
(2) having an inner diameter of 2.1 mm and a length of 20 cm
was looped by inserting both ends thereof into the jig, and
the both ends were slowly pulled down until a kink occurred
in the loop. The loop length (H) at the occurrence of kink
was obtained as indicator of the kink resistance. The shorter
the loop length, the higher the kink resistance. (See Fig.
1.)
[Measurement of dynamic viscoelasticity]
A specimen was twisted (torsion mode) at 10 rad/s over
an area 10 mm width and 38 mm length and was heated from -100
to 100°C at a heating rate of 2°C/min; the loss tangent tan5
and storage elastic modulus G' were measured at each
temperature by means of Rheometrics RDS-II.
[Tensile test]
1. Permanent set
A dumbbell specimen 50 mm in length (LO) , 15 mm in gauge
length, 5 mm in width and 1 mmt in thickness that was fixed
between chucks 30 mm apart was 100% strained (to a distance
of 60 mm between the chucks) at a stress rate of 30 mm/min,
maintained for 10 minutes and released for 10 minutes. The
length (L) was measured and the permanent set was determined
from the formula: Permanent set (%) : = L/LO1 x 100
2. Young's modulus
A JIS No. 3 dumbbell specimen was tested for the Young' s
modulus with a span of 30 mm, at a stress rate of 30 mm/min
and 23°C in accordance with JIS K 6301.
[Heat resistance]
Penetration temperature (°C)
A test specimen 1 mm thick was heated at a rate of 5°C/min
and a plane indenter 1.8 mm in diameter was pressed at 2 kg/cm2
in accordance with JIS K 7196. The penetration temperature
(°C) was determined from a TMA curve.
[Haze (%)]
A test specimen 1 mm thick was tested with digital
turbidity meter NDH-20D manufactured by NIPPON DENSHOKU to
determine the haze.
[Abrasion resistance test]
A test specimen 2 mm in thickness was tested with a
"Gakushin" abrasion tester manufactured by Toyo Seiki
Seisaku-Sho, Ltd., as follows. The tip of a 45R SUS abrasion
indenter weighing 470 g was covered with a cotton duck No. 10,
and was caused to abrade the specimen-at 23°C, reciprocating
100 times at a reciprocating rate of 33 reciprocating motions
per minute and with a stroke of 100 mm. -The gloss change' A
Gloss between before and after the abrasion was determined by:
(Gloss before abrasion - Gloss after abrasion)
A Gloss = — — r—r r : — x 100
Gloss before abrasion
[Melting point (Tm) and glass transition temperature ( T g ) ]
An endothermic curve was obtained by DSC, and the
temperature at a maximum peak point was obtained as Tm. The
measurement was performed as follows. A specimen was loaded
into an aluminum pan and heated to 200°C at a rate of 100°C/min.
The temperature was maintained at 200°C for 10 minutes and then
lowered to -150°C at a rate of 10°C/min. Then the temperature
was raised at 10°C/min to obtain the endothermic curve.
[Intrinsic viscosity [n]j
The intrinsic viscosity was measured at 135°C in decalin.
[Mw/Mn]
Mw/Mn was measured by GPC (gel permeation
chromatography) in an orthodichlorobenzene solvent at 140°C.
(Synthetic Example 1)
(Synthesis of syndiotactic polypropylene) (i-1)
Bulk polymerization of propylene was performed
according to a method disclosed in JP-A-H02-274763, with use
of a catalyst composed of diphenylmethylene (cyclopentadienyl)
fluorenyl zirconium dichloride and methylaluminoxane and in
the presence of hydrogen. The resultant syndiotactic
polypropylene had a melt flow index of 4.4 g/10 min, a GPC
molecular weight distribution of 2.3, a 13C-NMR syndiotactic
pentad ratio (r.r.r.r) of 0.823, and Tm of 127°C and Tc of 57°C
according to differential scanning calorimetry.
(Synthetic Example 2)
(Synthesis of syndiotactic propylene/ethylene copolymer)
(ii-1)
A 1.5-liter autoclave vacuum dried and purged with
nitrogen was charged with 750 ml of heptane at room temperature .
A 1.0 mmol/ml toluene solution of triisobutylaluminum
(hereinafter abbreviated to TIBA) was added in an"amount of
0.3 ml to achieve the amount of 0.3 mmol in terms of aluminum
atom. Thereafter, 50.7 liters (at 25°C and 1 atmospheric
pressure) of propylene was fed with stirring, and the
temperature was raised to 30°C. The system was then
pressurized with ethylene to 5.5 kg/cm2G. Subsequently, a
heptane solution (0.0002 mM/ml) of
diphenylmethylene (cyclopentadienyl) fluorenyl zirconium
dichloride and a toluene solution (0.002 mM /ml) of
triphenylcarbenium-tetra(pentafluorophenyl)borate
synthesized by common processes were added in amounts of 3.75
ml and 2.0 ml respectively to initiate copolymerization of
propylene and ethylene. The catalyst concentrations relative
to the system were 0,001 .mmol/liter for diphenylmethylene
(cyclopentadienyl)fluorenyl zirconium dichloride and 0.004
mmol/liter for triphenylcarbenium-tetra(pentafluorophenyl)
borate.
During the polymerization, the internal pressure was
maintained at 5. 5 kg/cm2G by continuously supplying ethylene.
After 30 minutes from the initiation of the polymerization,
the polymerization reaction was terminated by addition of
methyl alcohol, followed by degassing. The polymer solution
was recovered and was washed using an equivalent amount (1:1)
of an aqueous solution containing 5 ml of concentrated
hydrochloric acid per liter of water, and thereby the catalyst
residues were transferred to the aqueous phase. The
catalyst-mixed solution was allowed to stand, and the aqueous
phase was separated and removed. The residue was washed twice
with distilled water to complete separation of the
polymerization liquid phase from the aqueous phase. The
polymerization liquid phase thus separated was brought into
contact with a three-fold amount of acetone with vigorous
stirring to precipitate the polymer. After washing had been
adequately performed with acetone, the solid phase (copolymer)
was collected by filtration and was dried at 130°C and 350 miuHg
for 12 hours in a stream of nitrogen. The resultant
propylene/ethylene copolymer weighed 50 g and had an intrinsic
viscosity [r\] at 135°C in decalin of 2 . 4 dl/g, a glass transition
temperature Tg of -28°C, an ethylene content of 24.0 mol% and
a GPC molecular weight distribution (Mw/Mn) of 2.9. Any fusion
peak was not substantially observed under the aforementioned
DSC conditions.
(Synthetic Example 3}
(Synthesis of syndiotactic propylene/ethylene copolymer)
(ii-2)
A 2000-ml polymerizer sufficiently purged with nitrogen
was charged with 833 ml of dry hexane and triisobutylaluminum
(1.0 mmol) at room temperature. The internal temperature of
the polymerizer was raised to 90°C, and the pressure in the
system was increased to 0 . 6 6 MPa by feeding'propylene and was
adjusted to 0.69 MPa with ethylene. Subsequently, a toluene
solution of 0 . 001 mmol of diphenylmethylene (cyclopentadienyl)
(octamethyldihydrobenzoylfluorenyl) zirconium dichloride and
0.3 mmol in terms of aluminum of methylaluminoxane
(manufactured by Tosoh Finechem Corporation) was added into
the polymerizer. Polymerization was carried out at an
internal temperature of'90°C for 20 minutes while maintaining
the system pressure at 0.69 MPa with ethylene, and was
terminated by addition of 20 ml of methanol, followed by
degassing. The polymerization solution was poured into 2
liters of methanol to precipitate the polymer, and the polymer
was vacuum dried at 130°C for 12 hours. The resultant polymer
weighed 46. 4 g and had an intrinsic viscosity [t|] of 2.31dl/g,
a glass transition temperature Tg of -24°C, an ethylene content
of 19.0 mol% and a GPC molecular weight distribution (Mw/Mn)
of 2.3. Any fusion peak was not substantially observed under
the aforementioned DSC conditions.
[Example 1]
10 parts by weight of the syndiotactic homopolypropylene
(i-1) obtained in Synthetic Example 1, and 90 parts by weight
oi me synaiotactic propylene/ethylene copolymer (ii-1) of
Synthetic Example 2 were- kneaded together to give a propylene
polymer composition. The results are shown in Tables 1 and
2.
[Example 2]
The procedure-of Example 1 was repeated, except that the
syndiotactic propylene/ethylene copolymer (ii-1) was replaced
with the syndiotactic propylene/ethylene copolymer (ii-2)
obtained in Synthetic Example 3. The results are shown in
Tables 1 and 2.
[Example 3]
9 parts by weight of the syndiotactic homopolypropylene
(i-1) obtained in Synthetic Example 1, 81 parts by weight of
the syndiotactic propylene/ethylene copolymer (ii-1) of
Synthetic Example 2, and 10 parts by weight of a hydrogenated
terpene resin (P125 manufactured by YASUHARA CHEMICAL CO.,
LTD., Tg=68°C, average molecular weight: 1100) (iii-1) were
kneaded together to give a propylene polymer composition. The
results are shown in Tables 1 and 2.
[Example 4]
The procedure of Example 3 was repeated, except that the
syndiotactic homopolypropylene (i-1) was replaced with a
propylene random copolymer (Polypro F337D manufactured by
Sumitomo Mitsui Polyolefin Co., Ltd.) . The results are shown
in Tables 1 and 2.
[Comparative Example 1]
9 parts by weight of the syndiotactic homopolypropylene
(i-1) obtained in Synthetic Example 1, 81 parts by weight of
an ethylene/butene copolymer (TAFMER A4085 manufactured by
Mitsui Chemicals, Inc.), and 10 parts by weight of a
hydrogenated terpene resin (P125 manufactured by YASUHARA
CHEMICAL CO., LTD., Tg=68°C, average molecular weight: 1100)
(iii-1) were kneaded together to give a propylene polymer
composition. The results are shown in Tables•1.and 2.
(Table Removed)
[Example Ib]
10 parts by weight of the syndiotactic homopolypropylene
(i-1) obtained in Synthetic Example 1, and 90 parts by weight
of the syndiotactic propylene/ethylene copolymer (ii-1) of
Synthetic Example 2 were kneaded together to give a propylene
polymer composition. The composition was extruded using a
tube forming machine (manufactured by PLA GIKEN CO., LTD.)
constituted of a single screw extruder 40 mm in diameter fitted
with a tube die, under the following conditions:
•Extruder temperature setting:
Cl/C2/C3/C4/H/Dl/D2=190/200/200/200/200/200/200 (°C)
•Forming speed: 10 m/min
•Tube size: 2.1 mm in inner diameter and 3.0 mm in outer
diameter
The results of the measurements are shown in Table Ib.
[Example 2b]
The procedure of Example Ib was repeated, except that
the syndiotactic propylene/ethylene copolymer (ii-1) was
replaced with the syndiotactic propylene/ethylene copolymer
(ii-2) obtained in Synthetic Example 3. The results of the
measurements are shown in Table Ib.
[Example 3b]
9 parts by weight of the syndiotactic homopolypropylene
(i-1) obtained in Synthetic Example 1, 81 parts by weight of
the syndiotactic propylene/ethylene copolymer (ii-1) of
Synthetic Example 2, and 10 parts by weight of a hydrogenated
terpene resin (P125 manufactured by YASUHARA CHEMICAL CO.,
LTD., Tg=68°C, average mo.lecular weight: 1100) (iii-1) were
kneaded together to give a propylene polymer composition. A
tube was formed under the same conditions as in Example 1. The
results are shown in Table Ib.
[Example 4b]
The procedure of Example 3b was repeated, except that
the syndiotactic homopolypropylene (i-1) was replaced with a
propylene random copolymer (Polypro F337D manufactured by
Sumitomo Mitsui Polyolefin Co., Ltd.) . The results are shown
in Table Ib.
[Comparative Example Ib]
9 parts by weight of the syndiotactic homopolypropylene
(i-1) obtained in Synthetic Example 1, 8.1 parts by weight of
an ethylene/butene copolymer (TAFMER A4085 manufactured by
Mitsui Chemicals, Inc.), and 10 parts by weight of a
hydrogenated terpene resin (P125 manufactured by YASUHARA
CHEMICAL CO., LTD., Tg=68°C, average molecular weight: 1100)
(iii-1) .were kneaded together to give a propylene polymer
composition. A tube was formed under the same conditions as
in Example Ib. The results are shown in Table Ib.
(Table Removed)
INDUSTRIAL APPLICABILITY
.The propylene polymer composition according to the
present invention can give formed products well balanced and
excellent in transparency, impact resistance, flexibility,
heat resistance, scratch resistance 'and rubber elasticity.
The medical tubes of the propylene polymer composition
according to the present invention have well balanced
properties such as transparency, kink resistance, flexibility,
heat resistance, scratch resistance and rubber elasticity, and
adequately satisfy the performance expected as medical tubes.

WE CLAIM;
1. A medical tube comprising a propylene polymer composition, the propylene polymer composition comprising:
i) 1 to 40 parts by weight of a syndiotactic polypropylene; and
ii) 60 to 99 parts by weight of a syndiotactic propylene/ethylene copolymer that contains 99 to
55 mol% of a syndiotactic propylene component and 1 to 45 mol% of an ethylene
component; wherein the propylene polymer composition satisfies all the following properties (A), (B), (C), (D) and (E):
(A) the composition shows a loss tangent (tan 8) peak at a temperature in the range of -20 to 25 °C
according to dynamic viscoelasticity measurement (10 rad/s) in a torsion mode, and the peak value
is 0.5 or above;
(B) the storage elastic modulus G' at 20 °C from the dynamic viscoelasticity measurement is in
the range of 1.0x107 to 4.9xl08 dyn/cm2;
(C) the penetration temperature (°C) determined in accordance with JIS K 7196 is in the range of 60
to 160 °C;
(D) the composition has a permanent set of not more than 30% as determined after the composition
fixed between chucks 30 mm apart is 100% strained at a stress rate of 30 mm/min, maintained for
10 minutes and released for 10 minutes; and
(E) wherein the composition has a Young's modulus (YM) of not more than 100 MPa as determined
in accordance with JIS 6301.
2 The medical tube as claimed in claim 1, wherein the propylene polymer composition
comprises 5 to 30 parts by weight of the propylene polymer (i) and 95 to 70 parts by weight of the copolymer (ii).
3. The medical tube as claimed in claim 1 or claim 2, wherein the syndiotactic polypropylene
(i) has a syndiotactic pentad ratio (rrrr) determined by 13C-NMR of 0.5 or above, and a melt flow index (MFI) in the range of 0.1 to 50 g/10 min; and the copolymer (ii) has an intrinsic viscosity [n] of 0.01 to 10 dl/g as determined at 135 °C in decalin, a molecular weight distribution determined by GPC of not more than 4, and a glass transition temperature Tg of not more than -10 °C.