U.S. patent application number 10/171156 was filed with the patent office on 2003-03-27 for thermoplastic elastomeric resin composition and a process for the preparation thereof.
Invention is credited to Tamura, Akihiro, Tasaka, Michihisa.
Application Number | 20030060557 10/171156 |
Document ID | / |
Family ID | 26417841 |
Filed Date | 2003-03-27 |
United States Patent
Application |
20030060557 |
Kind Code |
A1 |
Tasaka, Michihisa ; et
al. |
March 27, 2003 |
Thermoplastic elastomeric resin composition and a process for the
preparation thereof
Abstract
The invention provides a process for the preparation of a
thermoplastic elastomeric resin composition comprising melt
kneading (a) 100 parts by weight of a block copolymer consisting of
at least two polymeric blocks (A) composed mainly of a vinyl
aromatic compound and at least one polymeric block (B) composed
mainly of a conjugated diene compound, and/or a hydrogenated block
copolymer obtained by hydrogenating said block copolymer, (b) 40 to
240 parts by weight of a non-aromatic softening agent for rubber,
(c) 5 to 300 parts by weight of polyethylene or a copolymer
composed mainly of ethylene, and (d) 5 to 60 parts by weight of
polypropylene or a copolymer composed mainly of propylene,
characterized in that the process comprises the following steps:
(I) melt kneading the whole amounts of components (a), (b) and (d)
and a part of component (c), and, at the same time or subsequently,
melt kneading these with (f) an organic peroxide, and (II) melt
kneading the product obtained from step (I) with the remaining part
of component (c), and component (c) is one which has been prepared
using a single site catalyst. The obtained composition is soft and
excellent in heat deformation resistance and mechanical strength,
moldability and processability. The present invention also provide
a thermoplastic elastomeric resin composition comprising the above
components (a), (c) and (d) in an amount of 100 parts by weight, 5
to 150 parts by weight and 5 to 80 parts by weight, respectively.
The composition is soft and excellent in heat deformation
resistance and mechanical strength, moldability and processability
and shows good results in the extraction tests.
Inventors: |
Tasaka, Michihisa; (Kawasaki
City, JP) ; Tamura, Akihiro; (Tokyo, JP) |
Correspondence
Address: |
PITNEY, HARDIN, KIPP & SZUCH LLP
685 THIRD AVENUE
NEW YORK
NY
10017-4024
US
|
Family ID: |
26417841 |
Appl. No.: |
10/171156 |
Filed: |
June 13, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10171156 |
Jun 13, 2002 |
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08890866 |
Jul 10, 1997 |
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6433062 |
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Current U.S.
Class: |
524/484 ;
524/425; 524/451; 524/492; 524/495 |
Current CPC
Class: |
C08L 53/025 20130101;
C08L 23/0815 20130101; C08L 53/025 20130101; C08L 91/06 20130101;
C08L 2312/00 20130101; C08L 91/08 20130101; C08L 23/0815 20130101;
C08L 91/00 20130101; C08L 23/0815 20130101; C08L 23/10 20130101;
C08L 53/00 20130101; C08L 2205/02 20130101; C08L 2205/035 20130101;
C08L 53/02 20130101; C08L 2205/03 20130101; C08L 23/10 20130101;
C08L 23/12 20130101; C08L 23/04 20130101; C08L 53/00 20130101; C08L
2666/24 20130101; C08L 2666/02 20130101; C08L 2666/24 20130101;
C08L 2666/24 20130101; C08L 2666/04 20130101; C08L 53/00 20130101;
C08L 2666/02 20130101; C08L 2666/04 20130101; C08L 2666/04
20130101; C08L 2666/02 20130101; C08L 23/0815 20130101; C08L 53/00
20130101; C08L 53/02 20130101; C08L 91/06 20130101; C08L 23/04
20130101; C08L 53/02 20130101; C08L 91/08 20130101; C08L 91/00
20130101; C08L 53/025 20130101 |
Class at
Publication: |
524/484 ;
524/425; 524/451; 524/492; 524/495 |
International
Class: |
C08K 003/26; C08K
003/34; C08K 005/01; C08K 003/04 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 13, 1997 |
JP |
HEI-9-76706 |
Nov 29, 1996 |
JP |
HEI-8-334855 |
Claims
1. A process for the preparation of a thermoplastic elastomeric
resin composition comprising melt kneading (a) 100 parts by weight
of a block copolymer consisting of at least two polymeric blocks
(A) composed mainly of a vinyl aromatic compound and at least one
polymeric block (B) composed mainly of a conjugated diene compound,
and/or a hydrogenated block copolymer obtained by hydrogenating
said block copolymer, (b) 40 to 240 parts by weight of a
non-aromatic softening agent for rubber, (c) 5 to 300 parts by
weight of polyethylene or a copolymer composed mainly of ethylene,
and (d) 5 to 60 parts by weight of polypropylene or a copolymer
composed mainly of propylene, characterized in that the process
comprises the following steps: (I) melt kneading the whole amounts
of components (a), (b) and (d) and a part of component (c), and, at
the same time or subsequently, melt kneading these with (f) an
organic peroxide, and (II) melt kneading the product obtained from
step (I) with the remaining part of component (c), and component
(c) is one which has been prepared using a single site
catalyst.
2. The process as described in claim 1, wherein a weight ratio of
the amount of component (c) used in step (I) and that in step (II)
is 90:10 to 10:90.
3. The process as described in claim 1, wherein component (f) is
used in an amount of 0.1 to 1.5 parts by weight per 100 parts by
weight of a total amount of components (a), (b), (c) and (d).
4. The process as described in claim 1, wherein 0.1 to 3.5 parts by
weight of a crosslinking aid per 100 parts by weight of a total
amount of components (a), (b), (c) and (d) are used together with
component (f) in step (I).
5. The process as described in claim 1, wherein the whole amount of
(e) at most 100 parts by weight of an inorganic filler is melt
meaded in the initial stage of step (I).
6. A thermoplastic elastomeric resin composition comprising (a) 100
parts by weight of a block copolymer consisting of at least two
polymeric blocks (A) composed mainly of a vinyl aromatic compound
and at least one polymeric block (B) composed mainly of a
conjugated diene compound, and/or a hydrogenated block copolymer
obtained by hydrogenating said block copolymer, (c) 5 to 150 parts
by weight of polyethylene or a copolymer composed mainly of
ethylene, and (d) 5 to 80 parts by weight of polypropylene or a
copolymer composed mainly of propylene, characterized in that
component (c) is one which has been prepared using a single site
catalyst.
7. The thermoplastic elastomeric resin composition as described in
claim 6, wherein the composition further comprises (b) 40 to 240
parts by weight of a non-aromatic softening agent for rubber.
8. The thermoplastic elastomeric resin composition as described in
claim 6, wherein the composition further comprises (e) 0.01 to 100
parts by weight of an inorganic filler.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a process for the
preparation of a thermoplastic elastomeric resin composition.
[0002] The present invention also relates to a thermoplastic
elastomeric resin composition.
PRIOR ART
[0003] Thermoplastic elastomeric resins which are rubber-like
materials, do not need a vulcanization process and have
thermoplastic resin-like molding processability are attracting
attention in the fields of auto parts, parts for electric
appliances, electric wire insulation, footwears and general goods,
and in the field of cap sealing materials.
[0004] Various types of such thermoplastic elastomeric resins have
been developed and put on sale, such as polyolefine type,
polyurethane type, polyester type, polystyrene type and polyvinyl
chloride type.
[0005] Among those, polystyrene type thermoplastic elastomeric
resins such as styrene-butadiene block copolymers (SBS) and
styrene-isoprene block copolymers (SIS) and hydrogenated resins
thereof have high softness and good rubber elasticity at normal
temperature. Further, thermoplastic elastomeric resin compositions
obtained from these show good processability.
[0006] However, these block copolymer compositions are
unsatisfactory in compression set at a high temperature,
particularly at 100.degree. C. and, moreover, tensile properties
deteriorate considerably at 80.degree. C. or more. Thus, such
compositions do not meet the levels of properties required in the
fields of vulcanized rubber.
[0007] Meanwhile, the thermoplastic elastomers mentioned above are
also attracting attention in the fields of cap sealing materials.
Particularly, polyolefin type thermoplastic elastomers are used
widely because of their high sanitary reliability and cheapness.
However, these polyolefin type thermoplastic elastomers are poor in
softness and, therefore, exhibit poor sealing property.
[0008] Alternatively, polystyrene type thermoplastic elastomeric
resins such as SBS and SIS and hydrogenated resins thereof have
high softness and good rubber elasticity at normal temperature.
Further, thermoplastic elastomeric resin compositions obtained from
these show good processability. Accordingly, these are used widely
as an alternate of vulcanized rubber. However, these polystyrene
type thermoplastic elastomer compositions cannot meet the n-heptane
extraction test of the tests of Notification No. 20 of the Japanese
Welfare Ministry, because softening agents such as paraffinic oil
are generally added to these compositions in order to control their
hardness. Accordingly, it is hard to use them as a cap sealing.
Alternatively, if the paraffinic oil is not used, the softness and
moldability of them deteriorate.
[0009] In order to solve such a drawback, there has been proposed a
composition containing polybutene or polyisobutene as a softening
agent. However, the composition disclosed are poor in heat
resistance at 120.degree. C.
[0010] Another resin compositions which comprise the block
copolymer used as component (a) in the present invention has been
proposed in Japanese Patent Application Laid-Open Nos.
Sho-53-138451/1978, 53-138453/1978, 53-138454/1978, 53-138456/1978,
53-138458/1978, 53-138460/1978 and 53-138461/1978. However, heat
resistance is poor.
[0011] The composition disclosed in Japanese Patent Application
Laid-Open No. 58-215446/1983 comprises isotactic polypropylene.
This composition is excellent in mechanical strength and heat
resistance. However, the hardness is in the D hardness area. Thus,
it cannot be said that the composition is excellent in sealing
property.
SUMMARY OF THE INVENTION
[0012] A purpose of the invention is to provide a process for the
preparation of a thermoplastic elastomer composition which is soft
and excellent in heat deformation resistance, mechanical strength,
moldability and processability.
[0013] The present inventors have noticed that an organic peroxide
generate radicals, which then effect crosslinking of polyethylene
and molecule cutting of polypropylene, particularly effect molecule
cutting of polypropylene to deteriorate the physical properties in
the elastomer composition obtained. We have now found that when a
smallest amount of polypropylene needed for increasing the
flowability during melting is added and an amount of polyethylene
for obtaining proper dispersion is used, it is possible to enhance
the crosslinking of polyethylene and dispersion of rubber component
and to prepare the thermoplastic elastomer composition having
excellent properties. This finding leads to the present
invention.
[0014] Thus, the present invention provides a process for the
preparation of a thermoplastic elastomeric resin composition
comprising melt kneading
[0015] (a) 100 parts by weight of a block copolymer consisting of
at least two polymeric blocks (A) composed mainly of a vinyl
aromatic compound and at least one polymeric block (B) composed
mainly of a conjugated diene compound, and/or a hydrogenated block
copolymer obtained by hydrogenating said block copolymer,
[0016] (b) 40 to 240 parts by weight of a non-aromatic softening
agent for rubber,
[0017] (c) 5 to 300 parts by weight of polyethylene or a copolymer
composed mainly of ethylene, and
[0018] (d) 5 to 60 parts by weight of polypropylene or a copolymer
composed mainly of propylene,
[0019] characterized in that the process comprises the following
steps:
[0020] (I) melt kneading the whole amounts of components (a), (b)
and (d) and a part of component (c), and, at the same time or
subsequently, melt kneading these with (f) an organic peroxide,
and
[0021] (II) melt kneading the product obtained from step (I) with
the remaining part of component (c),
[0022] and component (c) is one which has been prepared using a
single site catalyst.
[0023] In a preferred embodiment, a weight ratio of the amount of
component (c) used in step (I) and that in step (II) is 90:10 to
10:90.
[0024] In another preferred embodiment, component (f) is used in an
amount of 0.1 to 1.5 parts by weight per 100 parts by weight of a
total amount of components (a), (b), (c) and (d).
[0025] In another preferred embodiment, 0.1 to 3.5 parts by weight
of a crosslinking aid per 100 parts by weight of a total amount of
components (a), (b), (c) and (d) are used together with component
(f) in step (I).
[0026] In another preferred embodiment, the whole amount of
[0027] (e) at most 100 parts by weight of an inorganic filler is
melt meaded in the initial stage of step (I).
[0028] In another preferred embodiment, (h) at most 3.0 parts by
weight of an antioxidant per 100 parts by weight of a total amount
of components (a), (b), (c) and (d) are used in step (I).
[0029] In another preferred embodiment, an additional amount of
component (d) is added in step (II) and melt kneaded.
[0030] Another purpose of the invention is to provide a
thermoplastic elastomer composition which is soft and excellent in
heat deformation resistance, mechanical strength, moldability and
processability and used properly as a sealing material.
[0031] Thus the present invention provides a thermoplastic
elastomeric resin composition comprising
[0032] (a) 100 parts by weight of a block copolymer consisting of
at least two polymeric blocks (A) composed mainly of a vinyl
aromatic compound and at least one polymeric block (B) composed
mainly of a conjugated diene compound, and/or a hydrogenated block
copolymer obtained by hydrogenating said block copolymer,
[0033] (c) 5 to 150 parts by weight of polyethylene or a copolymer
composed mainly of ethylene, and
[0034] (d) 5 to 80 parts by weight of polypropylene or a copolymer
composed mainly of propylene,
[0035] characterized in that component (c) is one which has been
prepared using a single site catalyst.
[0036] In a preferred embodiment, the composition further
comprises
[0037] (b) 40 to 240 parts by weight of a non-aromatic softening
agent for rubber.
[0038] In another preferred embodiment, the composition further
comprises
[0039] (e) 0.01 to 100 parts by weight of an inorganic filler
PREFERRED EMBODIMENTS OF THE INVENTION
[0040] Component (a), Block Copolymer
[0041] Component (a) used in the invention is a block copolymer
consisting of at least two polymeric blocks (A) composed mainly of
a viny aromatic compound and at least one polymeric block (B)
composed mainly of a conjugated diene
[0042] compound, or a hydrogenated block copolymer obtained by
hydrogenating said block copolymer, or a mixture thereof, such as
vinyl aromatic compound-conjugated diene compound block copolymers
having a structure, A-B-A, B-A-B-A or A-B-A-B-A, or those obtained
by hydrogenating such. The block copolymer and/or the hydrogenated
block copolymer (hereinafter referred to as (hydrogenated) block
copolymer) contains 5 to 60% by weight, preferably 20 to 50% by
weight, of a vinyl aromatic compound. Preferably, the polymeric
block A composed mainly of a vinyl aromatic compound consists
wholly of a vinyl aromatic compound or is a copolymeric block
comprising more than 50% by weight, preferably at least 70% by
weight, of a vinyl aromatic compound and an optional component such
as a conjugated diene compound and/or a hydrogenated conjugated
diene compound (hereinafter referred to as (hydrogenated)
conjugated diene compound). Preferably, the polymeric block B
composed mainly of a (hydrogenated) conjugated diene compound is
composed solely of a (hydrogenated) conjugated diene compound or is
a copolymeric block comprising more than 50% by weight, preferably
at least 70% by weight, of a (hydrogenated) conjugated diene
compound with an optional component such as a vinyl aromatic
compound. The vinyl compound or the (hydrogenated) conjugated diene
compound may be distributed at random, in a tapered manner (i.e., a
monomer content increases or decreases along a molecular chain), in
a form of partial block or mixture thereof in the polymeric block A
composed mainly of a vinyl aromatic compound or the polymeric block
B composed mainly of a (hydrogenated) conjugated diene compound,
respectively. When two or more of the polymeric block A composed
mainly of a vinyl aromatic compound or two or more of the polymeric
block B composed mainly of a (hydrogenated) conjugated diene
compound are present, they may be same with or different from each
other in structure.
[0043] The vinyl aromatic compound to compose the (hydrogenated)
block copolymer may be one or more selected from, for instance,
styrene, .alpha.-methyl styrene, vinyl toluene and p-tert.-butyl
styrene, preferably styrene. The conjugated diene compound may be
one or more selected from, for instance, butadiene, isoprene,
1,3-pentadiene, and 2,3-dimethyl-1,3-butadiene, preferably
butadiene and/or isoprene.
[0044] Any micro structure may be selected in the polymeric block B
composed mainly of the conjugated diene compound. It is preferred
that the butadiene block has 20 to 50%, more preferably 25 to 45%,
of 1,2-micro structure. In the polyisoprene block, it is preferred
that 70 to 100% by weight of isoprene is in 1,4-micro structure and
at lest 90% of the aliphatic double bonds derived from isoprene is
hydrogenated.
[0045] A weight average molecular weight of the (hydrogenated)
block copolymer with the aforesaid structure to be used in the
invention is preferably 5,000 to 1,500,000, more preferably 10,000
to 550,000, further more preferably 100,000 to 550,000,
particularly 100,000 to 400,000. A number average molecular weight
is preferably 5,000 to 1,500,000, more preferably 10,000 to
550,000, particularly 100,000 to 400,000. A ratio of the weight
average molecular weight (Mw) to the number average molecular
weight (Mn), Mw/Mn, is preferably 10 or less, more preferably 5 or
less, particularly 2 or less.
[0046] Molecule structure of the (hydrogenated) block copolymer may
be linear, branched, radial or any combination thereof.
[0047] Many methods were proposed for the preparation of such block
copolymers. As described, for instance, in JP Publication
40-23798/1965, block polymerization may be carried out using a
lithium catalyst or a Ziegler catalyst in an inert solvent. The
hydrogenated block copolymer may be obtained by hydrogenating the
block copolymer thus obtained in the presence of a hydrogenation
catalyst in an inert solvent.
[0048] Examples of the (hydrogenated) block copolymer include SBS,
SIS, SEBS and SEPS. A particularly preferred (hydrogenated) block
copolymer in the invention is a hydrogenated block copolymer with a
weight average molecular weight of 50,000 to 550,000 which is
composed of polymeric block A composed mainly of styrene and
polymeric block B which is composed mainly of isoprene and in which
70 to 100% by weight of isoprene has 1,4-micro structure and 90% of
the aliphatic double bonds derived from isoprene is hydrogenated
More preferably, 90 to 100% by weight of isoprene has 1,4-micro
structure in the aforesaid hydrogenated block copolymer.
[0049] Component (b), Non-Aromatic Softening Agent for Rubber
[0050] Non-aromatic mineral oils and non-aromatic liquid or low
molecular weight synthetic softening agents may be used as
component (b) of the invention. Mineral oil softening agents used
for rubber are mixtures of aromatic cyclic ones, napththenic cyclic
ones and paraffinic ones. Those in which 50% or more of the whole
carbon atoms is in paraffinic chains are called a paraffinic type;
those in which 30 to 40% of the whole carbon atoms is in naphthenic
rings are called a naphthenic type; and those in which 30% or more
of the whole carbon atoms is in aromatic rings are called an
aromatic type. Mineral oil softening agents for rubber to be used
as component (b) according to the invention are preferably of the
aforesaid paraffinic or naphthenic type. Aromatic softening agents
are improper, because the dispersion in component (a) is poor.
Paraffinic ones are preferred as component (b). Among the
paraffinic ones, those with a less content of aromatic cyclic
components are particularly preferred.
[0051] The non-aromatic softening agents for rubber have a kinetic
viscosity at 37.8.degree. C. of 20 to 500 cSt, a pour point of -10
to -15.degree. C. and a flash point (COC) of 170 to 300.degree.
C.
[0052] Component (b) is blended in an amount of at most 240 parts
by weight, preferably at most 180 parts by weight, and at least 40
parts by weight, preferably 80 parts by weight, per 100 parts by
weight of component (a). If the amount exceeds the upper limit,
bleedout of softening agent occurs easily and stickiness may be
given to the final products in some cases and the mechanical
properties deteriorate. If the amount is below the lower limit,
there is no problem in practice, but a load to the extruder
increases during the process and molecule cutting occurs due to
exothermic shearing. The softness of the composition obtained
deteriorates, too.
[0053] Component (c), Polyethylene or a Copolymer Composed Mainly
of Ethylene
[0054] Which Is Prepared Using a Single Site Catalyst
[0055] As the polyethylene or a copolymer composed mainly of
ethylene which is prepared using a single site catalyst, use may be
made of one or more substances selected from polyethylene, for
instance, high density polyethylene (polyethylene prepared in a low
pressure method), low density polyethylene (polyethylene prepared
in a high pressure method), linear low density polyethylene
(copolymers of ethylene with a smaller amount, preferably 1 to 10
molar % of .alpha.-olefin such as butene-1, hexene-1 or octene-1);
and olefinic copolymers such as ethylene-propylene copolymer,
ethylene-vinyl acetate copolymer and ethylene-acrylate copolymer.
Particularly preferable substances are ethylene-octene copolymer
having a polymer density of at most 0.90 g/cm.sup.3 or
ethylene-hexene copolymer having a polymer density of at least 0.90
g/cm.sup.3 which are prepared using a metallocene catalyst (single
site catalyst). When Tm of these copolymer is not higher than
100.degree. C., it is necessary to add and crosslink them by the
time of crosslinking at the latest. Tm disappears by the
crosslinking and, therefore, fusion of octene or hexene does not
occur. If the addition of them is carried out after the
crosslinking, fusion at 30 to 60.degree. C. of octene or hexene
remains and, therefore, the heat resistance is decreased.
[0056] The (co)polymer used as component (c) includes olefinic
polymers which are prepared using a catalyst for olefine
polymerization which is prepared in accordance with the method
described in Japanese Patent Application Laid-Open
Sho-61-296008/1986 and which is composed of a carrier and a
reaction product of metallocene having at least one metal selected
from the 4b group, 5b group and 6b group in the periodic table with
alumoxane, the reaction product being formed in the presence of the
carrier.
[0057] Another example of component (c) is an olefinic polymer
prepared using a metal coordinated complex described in Japanese
Patent Application Laid-Open Hei-3-163008, which metal coordinated
complex contains a metal selected from the group 3 (except
scandium), groups 4 to 10 and the lanthanoid group and a
delocalized .pi.-bonding part substituted by a constrained inducing
part, and is characterized in that said complex has a constrained
geometrical form around said metal atom, and a metal angle between
a center of the delocalized substituted .pi.-bonding part and a
center of at least one remaining substituted part is less than that
in a comparative complex which is different from it only in that a
constrained inducing substituted part is substituted with a
hydrogen, and wherein in each complex having further at least one
delocalized substituted .pi.-bonding part, only one, per metal
atom, of the delocalized substituted .pi.-bonding parts is
cyclic.
[0058] The (co)polymer used as component (c) has an MFR determined
at 190.degree. C. and a load of 2.16 kg of preferably 0.1 to 10.0
g/10 min., more preferably 0.3 to 5.0 g/l 0 min. In the present
composition, MFR of 0.3 to 2.0 g/10 min. is particularly
preferred.
[0059] In the present process, component (c) is blended in an
amount of at most 300 parts by weight, preferably at most 250 parts
by weight, and preferably at least 5 parts by weight, per 100 parts
by weight of component (a). If the amount is below the lower limit,
the present effects cannot be obtained. If the amount exceeds the
upper limit, softness of the elastomer composition obtained is lost
and bleedout of softening agent (b) occurs easily.
[0060] In the present composition, component (c) is contained in an
amount of at most 150 parts by weight, preferably at most 130 parts
by weight, and preferably at least 5 parts by weight, more
preferably at least 70 parts by weight, per 100 parts by weight of
component (a). If the amount is below the lower limit, softness is
lost. If the amount exceeds the upper limit, the heat resistance of
the elastomer composition deteriorates.
[0061] Component (d), Polypropylene or a Copolymer Composed Mainly
of Propylene
[0062] The polypropylene or a copolymer composed mainly of
propylene attains an effect of improving dispersion of the rubber
in the composition obtained so as to improve appearance of a molded
article. Further, the heat resistance may be also improved. The
component is an olefinic (co)polymer which is pyrolyzed by the heat
treatment in the presence of peroxide to decrease its molecular
weight and, therefore, its melting flowability increases. Examples
of such include isotactic polypropylenes, and copolymers of
propylene with other .alpha.-olefine such as ethylene, 1-butene,
1-hexene or 4-methyl-1-pentene.
[0063] Preferably, component (d) has Tm of 150 to 167.degree. C.
and .DELTA.Hm of 25 to 83 mJ/mg, as determined by DSC (differential
scanning calorimetry) on its homopolymeric part. Crystallinity may
be estimated from Tm and .DELTA.Hm. If Tm and .DELTA.Hm are out of
the aforesaid ranges, rubber elasticity at 100.degree. C. or higher
of the elastomer composition obtained is not improved.
[0064] In the present process, component (d) has an MFR (ASTM
D-1238, Condition L, 230.degree. C.) of preferably 0.1 to 50 g/10
min., more preferably 0.5 to 20 g/10 min. If the MFR is less than
0.1 g/10 min., moldability of the elastomer composition obtained
deteriorates. If it exceeds 50 g/10 min., rubber elasticity of the
elastomer composition obtained deteriorates.
[0065] In the present process, component (d) is blended in an
amount of at most 60 parts by weight, preferably at most 30 parts
by weight, and at least 5 parts by weight, preferably at least 10
parts by weight, per 100 parts by weight of component (a). If the
amount is less than the lower limit, moldability of the elastomer
composition obtained deteriorates. If it exceeds the upper limit,
the elastomer composition obtained is too hard and lacks softness,
so that an article with rubber-like touch cannot be obtained and,
further, bleedout is observed.
[0066] The component (d) may be added and melt kneaded after the
melt kneading in the presence of an organic peroxide to control the
hardness of the composition or to control moldability such as
appearance or shrinkage. In this case, component (d) has an MFR
(ASTM D-1238, Condition L, 230.degree. C.) of preferably 0.1 to 200
g/10 min., more preferably 0.5 to 60 g/10 min. If the MFR is not
within the above range, the aforesaid drawbacks occur. The amount
in this case is at most 50 parts by weight, preferably at most 20
parts by weight, and at least 5 parts by weight, preferably at
least 10 parts by weight, per 100 parts by weight of component (a).
If the amount is less than the lower limit, adjustment of
moldability of the elastomer composition obtained is insufficient.
If it exceeds the upper limit, the elastomer composition obtained
is too hard and lacks softness, so that an article with rubber-like
touch cannot be obtained.
[0067] In the present elastomer composition, component (d) is
contained in an amount of 5 to 80 parts by weight, preferably 30 to
50 parts by weight, per 100 parts by weight of component (a). If
the amount is below the lower limit, the moldability of the
elastomer composition was poor. If the amount exceeds the upper
limit, the softness and rubber elasticity of the elastomer
composition deteriorate.
[0068] Component (e), Inorganic Filler
[0069] Inorganic fillers may be blended, if needed. The fillers
improve some physical properties, such as compression set of a
molded article, and further offer an economical advantage as an
extender. Any conventional inorganic fillers may be used, such as
calcium carbonate, talc, magnesium hydroxide, mica, clay, barium
sulfate, natural silica, synthetic silica (white carbon), titanium
oxide, and carbon black. Among those, calcium carbonate and talc
are particularly preferred, which meet the test of Notification No.
20 of the Japanese Welfare Ministry.
[0070] The inorganic filler may be blended in an mount of at most
100 parts by weight per 100 parts by weight of component (a). If
the amount exceeds 100 parts by weight, mechanical strength of the
elastomer composition obtained is very low and, further, its
hardness is so high that its flexibility is lost and an article
with rubber-like touch cannot be obtained. In addition, the
moldability deteriorates.
[0071] Component (f), Organic Peroxide
[0072] An organic peroxide enhances the crosslinking of component
(c) and molecule cutting of component (d) to increase flowability
of the composition during melt kneading and, therefore, makes
dispersion of a rubber component good. Examples of the organic
peroxides used in the invention include dicumyl peroxide,
di-tert.-butyl peroxide, 2,5-dimethyl-2,5-di(tert.-butylperoxy)
hexane, 2,5-dimethyl-2,5-di(tert.-- butylperoxy) hexine-3,
1,3-bis(tert.-butylperoxyisopropyl) benzene,
1,1-bis(tert.-butylperoxy)-3,3,5-trimethylcyclohexane,
n-butyl-4,4,-bis(tert.-butylperoxy)valerate, benzoylperoxide,
p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide,
tert.-butylperoxy benzoate, tert.-butylperoxyisopropyl carbonate,
diacetyl peroxide, lauroyl peroxide, and tert.-butylcumyl peroxide.
Among those, most preferred are
2,5-dimethyl-2,5-di(tert.-butylperoxy)hexane and
2,5-dimethyl-2,5-di(tert.-butylperoxy) hexine-3 in terms of smell,
coloring and scorch stability.
[0073] The amount of component (f) added is determined with
consideration of the-amounts of the aforesaid components (a) to (e)
and, particularly, the quality of the thermoplastic elastomer
obtained. It is blended preferably in an amount of at most 1.5
parts by weight, particularly at most 1.0 parts by weight, and
preferably at least 0.1 part by weight, per 100 parts by weight of
a total amount of components (a) to (d). If the amount is more than
the upper limit, the moldability becomes worse, while it is less
than the lower limit, it tends not to attain sufficient
crosslinking and, therefore, the heat resistance and mechanical
strength of the elastomer obtained becomes worse.
[0074] Component (g), Crosslinking Aid
[0075] In the crosslinking treatment in the presence of the organic
peroxide in the process for the preparation of a thermoplastic
elastomer composition according to the invention, a crosslinking
aid may be blended and thereby uniform and effective crosslinking
reaction may be carried out. Examples of the crosslinking aid
include polyvalent vinyl monomers such as divinylbenzene,
triallylcyanurate, vinyl butylate and vinyl stearate and polyvalent
methacrylate monomers such as ethyleneglycol dimethacrylate,
diethyleneglycol dimethacrylate, triethyleneglycol dimethacrylate,
polyethyleneglycol dimethacrylate, trimethylolpropane
trimethacrylate and allyl methacrylate, and dially esters of
orthophthalic acid, isophthalic acid or terephthalic acid. Among
these, triethylenegloycol dimethacrylateis particularly preferred,
because this is easy to handle and attains a well compatibility
with component (c), a main component in the composition, and this
has a solubilizing action for the peroxide to act as a dispersion
aid for the peroxide, so that the crosslinking action in the heat
treatment is uniform and efficient to give a cross-linked
thermoplastic elastomer with a good balance between hardness and
rubber elasticity.
[0076] The amount of the crosslinking aid blended is also
determined with consideration of the amounts of the aforesaid
components (a) to (e) and, particularly, the quality of the
thermoplastic elastomer obtained. It is blended preferably in an
amount of at most 3.5 parts by weight, particularly at most 2.5
parts by weight, and preferably at least 0.1 part by weight, per
total 100 parts by weight of components (a) to (d). If the amount
is more than the upper limit, a degree of crosslinking tends to
decrease because of self polymerization, while it is less than the
lower limit, it tends not to attain the effect of this material
sufficiently.
[0077] Component (h), Antioxidant
[0078] Antioxidant may also be added, if needed, such as phenolic
antioxidant such as 2,6-di-tert.-butyl-p-cresol,
2,6-di-tert.-butylphenol- , 2,4-di-methyl-6-tert.-butylphenol,
4,4-dihydroxydiphenyl, and
tris(2-methyl-4-hydroxy-5-tert.-butylphenyl)butane, phosphite type
antioxidants and thioether type antioxidants. Among those, the
phenolic antioxidants and the phosphite type antioxidants are
preferred.
[0079] The amount of the antioxidant is preferably 3 parts by
weight or less, more preferably 1 part by weight or less, per total
100 parts by weight of components (a) to (d).
[0080] In the present invention, it is possible to blend various
conventional additives such as anti-blocking agents, sealing
property-improving agents, heat stabilizers, light stabilizers, UV
absorbers, lubricants, nucleating agents and colorants in addition
to the aforesaid components, depending on the applications.
[0081] The present process will be further explained
hereinafter.
[0082] The present process comprises the following steps:
[0083] (I) melt kneading the whole amounts of components (a), (b)
and (d) and optionally component (e) and a part of component (c),
and, at the same time or subsequently, melt kneading these with (f)
an organic peroxide, and
[0084] (II) melt kneading the product obtained from step (I) with
the remaining part of component (c).
[0085] In the present process, component (c) is portionwise added
and melt kneaded in steps (I) and (II). A weight ratio of the
amount of component (c) used in step (I) and that in step (II) is
preferably 90:10 to 10:90, more preferably 50:50 to 20:80. If the
amount melt kneaded in step (I) is too much, a load to the extruder
increases during the process because of an excess proceeding of
crosslinking and molecule cutting occurs due to exothermic
shearing. Moreover, dispersion of component (c) deteriorates so
that this affects adversely the properties of the elastomer
composition obtained. If the amount melt kneaded in step (I) is too
little, proper crosslinking cannot be obtained.
[0086] When component (g), crosslinking aid, mentioned above is
used, it is preferably melt kneaded together with component (f),
organic peroxide in step (I), whereby the aforesaid effects may be
attained.
[0087] Next, one embodiment of the present process will be
described. For example, the whole amounts of components (a), (b)
and (d) and component (e), if used, and a part of component (c) are
melt kneaded, together with optional additives such as an
antioxidant, a light stabilizer, a pigment, a flame retardant and a
lublicant. The means for melt kneading are not restricted to
particular ones and any conventional means may be used, such as
single screw extruders, twin screws extruders, rolls, Banbury
mixers, and various kneaders. A melt kneading temperature is
preferably 160 to 180.degree. C. Next, component (f) and preferably
component (g) are added to the product obtained by this melt
kneading and melt kneaded together, whereby partial crosslinking of
component (c) may be attained. The melt kneading may be carried out
generally on, for example, twin screws extruders or Banbury mixers.
Subsequently, the remaining part of component (c) and, if desired,
component (d) is further added to the product obtained by this melt
kneading and melt kneaded. A melt kneading temperature for
crosslinking is preferably 180 to 240.degree. C., more preferably
180 to 220.degree. C. This melt kneading may be carried out using,
for example, single screw extruders, twin screws extruders, rolls,
Banbury mixers, and various kneaders. For example, when a twin
screws extruder with an L/D ratio of 47 or more or a Banbury mixer
is used, it is possible to carry out the aforesaid process
continuously.
[0088] The thermoplastic elastomeric resin composition of the
present invention will be further explained hereinafter.
[0089] The present elastomer composition comprises 100 parts by
weight of composnent (a), 5 to 150 parts by weight of component (c)
and 5 to 80 parts by weight of component (d). These components are
described specifically hereinbefore.
[0090] The present composition may contain any other components
mentioned above, if needed.
[0091] The present composition may be prepared by melt kneading the
aforesaid components (a), (c) and (d) in any order or at the same
time.
EXAMPLES
[0092] The present invention is further elucidated with reference
to the following Examples and Comparison Examples, which is not
intended to limit the invention. The evaluation methods used were
as follows:
[0093] 1) Hardness: determined in accordance with the Japanese
Industrial Standards (JIS) K 7215. Pressed sheets having a
thickness of 6.3 mm were used as test pieces.
[0094] 2) Tensile strength: determined in accordance with JIS K
6301 using a test piece which was obtained by punching out a
pressed sheet having a thickness of 1 mm by a No. 3 dumbbell die.
The tensile speed was 500 mm/min. In Examples 1 to 5 and Comparison
Examples 1 to 10, the test temperature was room temperature
(23.degree. C.), 60.degree. C. or 80.degree. C.
[0095] 3) Tensile elongation: determined in accordance with JIS K
6301 using a test piece which was obtained by punching out a
pressed sheet having a thickness of 1 mm by a No. 3 dumbbell die.
The tensile speed was 500 mm/min.
[0096] 4) Stress at 100% elongation: determined in accordance with
JIS K 6301 using a test piece which was obtained by punching out a
pressed sheet having a thickness of 1 mm by a No. 3 dumbbell die.
The tensile speed was 500 mm/min.
[0097] 5) Impact resilience: determined in accordance with BS903
using a pressed sheet having a thickness of 4 mm as a test
piece.
[0098] 6) Compression set: determined in accordance with JIS K 6262
using a pressed sheet having a thickness of 6.3 mm as a test piece.
Conditions: 25% deformation at 100.degree. C..times.70 hrs in
Examples 1 to 5 and Comparison Examples 1 to 10, or at 125.degree.
C..times.1 hr in Examples 6 to 11 and Comparison Examples 11 to
17.
[0099] 7) Tearing strength: determined in accordance with JIS K
6301 using a test piece which was obtained by punching out a
pressed sheet having a thickness of 2.5 mm by a B type dumbbell
die. The tensile speed was 500 mm/min.
[0100] 8) Oil resistance: determined in accordance with JIS K 6301
using a test piece which was obtained by punching out a pressed
sheet having a thickness of 1 mm by a No. 3 dumbbell die. ASTM No.
2 oil was used. Tensile strength retained and elongation retained
were measured after dipping at 100.degree. C..times.24 hrs. The
tensile speed was 500 mm/min.
[0101] 9) Moldability: determined by molding a composition into a
sheet of 12.5.times.13.5.times.1 mm on a 120 tons injection molding
machine in the following conditions.
1 molding temperature 220.degree. C., mold temperature 40.degree.
C., injection rate 55 mm/sec., injection pressure 1400 kg
/cm.sup.2, holding pressure 400 kg /cm.sup.2, injection time 6
seconds, cooling time 45 seconds.
[0102] It was observed whether delamination, deformation or flow
marks which extremely deteriorated appearance was present or
not.
2 .circleincircle. very good .largecircle. good X bad
[0103] 10) Extraction tests: carried out according to the test of
Notification No. 20 of the Japanese Welfare Ministry, using a
pressed sheet having a thickness of 1.0 mm as a test piece.
[0104] Test items:
[0105] Oily foods elution test (eluting solution:n-heptane),
[0106] Aqueous foods elution test (eluting solution:water),
[0107] Alcohol elution test (eluting solution: 20% ethanol),
and
[0108] Determination of the amount of potassium permanganate
consumed by the eluted product.
[0109] 11) Bleed-out property: the molded sheet obtained from (9)
was compressed by 50% under the conditions of 100.degree.
C..times.22 hrs. It was observed whether bleeding or blooming of
low molecular weight substances was visually observed or not, and
whether stickiness was felt or not in tough by fingers.
3 .largecircle. good X bad
[0110] 12) DSC, determined as follows:
[0111] The aforesaid molded article was cut to obtain an about 20
mg piece. This was used as a sample for the determination of DSC.
DSC was determined using a DSC220C, SII, ex Seiko Electronic
Industries Ltd., in a range of -50.degree. C. to 200.degree. C. at
a rate of 10.degree. C./min. to obtain glass transition
temperature, Tg.sub.1, melting point, Tm.sub.1 and Tm.sub.2, and
crystallization temperature, Tc.sub.1 and Tc.sub.2, wherein
Tm.sub.1 and Tc.sub.1 are attributed to polyethylene and Tm.sub.2
and Tc.sub.2 to polypropylene.
[0112] 13) Gloss: determined in accordance with JIS Z 8741 on the
aforesaid molded article. The larger the values are, the more
smooth the surface is, and the smaller the values are, the more
rough the surface is.
[0113] Materials used:
[0114] Component (a): hydrogenated block copolymer, Septon 4077,
ex. Kuraray Inc.,
[0115] styrene content: 30% by weight,
[0116] isoprene content: 70% by weight,
[0117] number average molecular weight: 260,000,
[0118] weight average molecular weight: 320,000,
[0119] molecular weight distribution: 1.23, and
[0120] hydrogenation ratio: at least 90%.
[0121] Component (b): softening agent for rubber, Diana Process
Oil, PW-90, ex Idemitsu Kosan Co.,
[0122] weight average molecular weight: 539,
[0123] paraffinic carbon content: 71%, and
[0124] naphthenic carbon content: 29%.
[0125] Component (c):
[0126] (c-1) ethylene-octene copolymer, Engage EG8150, trade mark,
ex Dow Chemical Japan Inc.,
[0127] density: 0.868 g/cm.sup.3,
[0128] melt index, determined at 190.degree. C. and a load of 2.16
kg: 0.5 g/10 min.
[0129] (c-2) ethylene-hexene copolymer, SP2520, trade mark, ex
Mitsui Petrochemical Industries Inc.,
[0130] density: 0.928 g/cm.sup.3,
[0131] melt index, determined at 190.degree. C. and a load of 2.16
kg 1.7 g/10 min.
[0132] (c-3) polyethylene for comparison, which had not been
prepared with a single site catalyst,
[0133] V-0398CN, trade mark, ex Idemitsu Petrochemical Co.,
[0134] density: 0.907 g/cm.sup.3,
[0135] melt index, determined at 190.degree. C. and a load of 2.16
kg: 3.3 g/10 min.
[0136] Component (d): propylene homopolymer, PP CJ700, ex Mitsui
Petrochemical Industries Inc.,
[0137] crystallization degree: Tm 166.degree. C., .DELTA.Hm 82
mJ/mg,
[0138] Component (e): inorganic filler,
[0139] calcium carbonate, RS400, trade mark, ex Sankyo Seihun
Co.,
[0140] used in Examples 1 to 5 and Comparison Examples 1 to 10.
[0141] talc, JA13R, ex Asada Seihun Co.,
[0142] used in Examples 6 to 11 and Comparison Examples 11 to
17.
[0143] Component (f): organic peroxide KayahexaAD, trade mark, ex
Kayaku Akzo Co.
[0144] Component (g): crosslinking aid
[0145] NK ester 3G, trade mark, ex Shin-Nakamura Chemical Co.,
[0146] type: triethylene glycol dimethacrylate
[0147] Component (h): antioxidant
[0148] Irganox B220, trade mark, ex Nippon Ciba-Geigy
Examples 1 to 5 and Comparison Examples 1 to 10
[0149] Each component was used in the amount indicated in Tables 1
and 3 in part by weight. First, the whole amounts of components
(a), (b), (d), (e) and (h) and a part of component (c), which
amount is indicated before symbol "+" in Tables 1 and 3, were
charged all together into a twin-screw extruder with an L/D of 62.5
and started to be melt kneaded at a kneading temperature of 180 to
240.degree. C. and a screw rotation speed of 350 rpm. Next, the
whole amounts of components (f) and (g) were side fed and the melt
kneading was still continued. Subsequently, the remaining part of
component (c), which amount is indicated after symbol "+" in Tables
1 and 3, was side fed, melt kneaded and pelletized. The pellets
obtained were put in a predetermined mold and then pressed in the
conditions of 220.degree. C. and 50 kg/cm.sup.2 to prepare each
sheet for the aforesaid evaluation methods (1) to (8). For the
evaluation methods (9), (11), (12) and (13), the pellets thus
obtained were injection molded in the conditions described in
evaluation method (9) and subjected to each test.
[0150] The results are as shown in Tables 2 and 4.
4TABLE 1 Component, Example part by weight 1 2 3 4 5 (a) 100 100
100 100 100 (b) 150 150 140 140 150 (c-1) 30 + 0 10 + 0 10 + 0 10 +
0 30 + 0 (c-2) 50 + 25 50 + 25 50 + 50 50 + 100 50 + 25 (d) 15 15
15 15 15 (e) 60 60 60 60 0 (f)* 0.75 0.75 0.75 0.75 0.75 (g)* 1.35
1.35 1.35 1.35 1.35 (h)* 0.4 0.4 0.4 0.4 0.4 *per 100 parts by
weight of the total amount components (a) to (d).
[0151]
5 TABLE 2 Example 1 2 3 4 5 Properties of the composition Specific
gravity 0.98 0.98 0.99 0.98 0.90 Hardness, 58 65 69 80 75 after HDA
15 seconds Tensile strength, 9.5 11.9 13.1 15.1 12.4 MPa 23.degree.
C. 60.degree. C. 1.5 1.8 2.1 3.5 2.0 80.degree. C. 0.5 0.7 1 1.6
0.7 Tensile elongation, % 910 780 840 850 1180 Stress at 100% 1.5
2.1 2.2 3.1 2.0 elongation, MPa Tearing strength, kN/m 27 35 37 42
35 Impact resilience. % 42 41 41 40 55 Compression set, % 63 63 66
68 82 Oil resistance Tensil strength 8 10 12 15 10 retained, %
Elongation retained, % 11 12 13 14 14 Moldability .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle. leedout
property .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. Results of DSC, .degree. C. Tg.sub.1 29.4 -- -- -- --
Tm.sub.1 115.5 -- -- -- -- Tm.sub.2 -- -- -- -- -- Tc.sub.1 86.6 --
-- -- -- Tc.sub.2 102.3 -- -- -- -- Gloss, % 37 -- -- -- --
[0152]
6 TABLE 3 Comparative Example Component, part by weight 1 2 3 4 5 6
7 8 9 10 (a) 100 100 100 100 100 100 100 100 100 100 (b) 150 20 250
140 140 140 140 140 150 150 (c-1) 30 + 0 10 + 0 10 + 0 3 + 0 10 + 0
10 + 0 10 + 0 10 + 0 30 + 0 -- (c-2) 50 + 25 50 + 100 50 + 100 0 50
+ 300 50 + 50 50 + 50 50 + 50 75 + 0 -- (c-3) for comparison -- --
-- -- -- -- -- -- -- 105 (d) 15 15 15 15 15 0 80 15 15 15 (e) 60 60
60 60 60 60 60 150 60 60 (f)* 0 0.75 0.75 0.75 0.75 0.75 0.75 0.75
0.75 0.75 (g)* 0 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.35 (h)*
0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 *per 100 parts by weight of
the total amount of components (a) to (d).
[0153]
7 TABLE 4 Comparison Example 1 2 3 4 5 6 7 8 9 10 Properties of the
composition Specific gravity 0.98 1 0.94 0.99 0.96 0.99 0.98 1.08
0.98 0.98 Hardness, 59 93 54 48 91 58 83 80 63 65 after HDA 15
seconds Tensile strength, MPa 23.degree. C. 15.5 18.5 9.8 7.2 19.8
4.8 11.9 3.2 7.5 12.0 60.degree. C. 0.3 -- -- -- 4.8 -- 2 -- -- --
80.degree. C. 0 -- -- -- 2 -- 1.1 -- -- Tensile elongation, % 800
230 450 480 790 80 670 240 650 480 Stress at 100% elongation, MPa
1.3 5.3 1.8 1.2 5.2 -- 4.2 2.8 1.5 2.1 Tearing strength, kN/m 30 62
30 -- 74 15 51 12 35 27 Impact resilience, % 46 35 38 -- 34 40 36
25 41 42 Compression set, % 67 83 70 -- 72 73 68 80 55 63 Oil
resistance Tensile strength retained, % 0 -- -- -- 31 -- 18 10 18
10 Elongation retained, % 0 -- -- -- 65 -- 23 5 15 12 Moldability
.largecircle. X .largecircle. X .largecircle. X .largecircle. X
.largecircle. .DELTA. Bleedout property .largecircle. .largecircle.
X .largecircle. X .largecircle. X .largecircle. .largecircle.
.largecircle. Results of DSC, .degree. C. Tg.sub.1 28.2 -- -- -- --
-- -- -- -- -- Tm.sub.1 116.7 -- -- -- -- -- -- -- -- -- Tm.sub.2
157.4 -- -- -- -- -- -- -- -- -- Tc.sub.1 87.2 -- -- -- -- -- -- --
-- -- Tc.sub.2 102.8 -- -- -- -- -- -- -- -- -- Gloss, % -- -- --
-- -- -- -- -- -- 10
[0154] The resin composition in Example 1 was prepared according to
the process of the present invention, while one in Comparison
Example 1 was prepared in the same conditions as in Example 1,
except that components (f) and (g) were not added. It was found
that the oil resistance was very low in Comparison Example 1. From
the results of DSC determination, in Example 1, the melting
temperature of polyethylene, Tm.sub.1, decreased and the melting
temperature of polypropylene, Tm.sub.2, disappeared. The
crystallization temperatures of polyethylene and polypropylene,
Tc.sub.1 and Tc.sub.2, respectively, decreased slightly. From these
data, it is considered that some interaction between polyethylene
and polypropylene occured, whereby a state near partial
compatibility one was obtained. The glass transition temperature,
Tg.sub.1, increased, and become considerably high in Example 1. It
is considered that this was due to the considerable phase
separation of crystal and non-crystal parts of polyethylene, as a
result of the process of the present invention.
[0155] In Examples 2 to 4, the amount of component (c) added was
varied. All of the compositions exhibited good characteristic
values. It was found that the larger the amount was, the better the
characteristic values were. The composition in Example 5 did not
contain component (e). It also exhibited good characteristic
values.
[0156] Meanwhile, in Comparison Example 2, the amount of component
(b) added was below the range of the present invention. The tensile
strength was very low and the moldability was poor. In Comparison
Example 3, the amount of component (b) added was above the range of
the present invention. The tensile elongation was very low and
bleedout occured considerably. In Comparison Example 4, the amount
of component (c) added was below the range of the present invention
and was introduced all into the extruder in the former kneading
step. The tensile elongation was very low and the moldability was
poor. In Comparison Example 5, the amount of component (c) added
was above the range of the present invention. The bleedout property
was poor. In Comparison Example 6, component (d) was not blended.
The tensile elongation was very low and the moldability was poor.
In Comparison Example 7, the amount of component (d) added was
above the range of the present invention. The tensile elongation
was low and the bleedout property was poor. In Comparison Example
8, the amount of component (e) added was above the range of the
present invention. The tensile elongation, tearing strength, impact
resilience and oil resistance were poor and the moldability was
also poor. In Comparison Example 9, wherein the composition was
same as in Example 1, all of the components was melt kneaded all
together. The tensile strength and tensile elongation were lower
than those in Example 1. It was found that the hardness was high
and softness decreased. In Comparison Example 10, use was made of a
normal polyethylene which had not been polymerized by a single site
catalyst, in place of component (c) in Example 1. The tensile
elongation was lower, the hardness was higher and the softness
decreased, compared to those in Example 1. It was also found that
the gloss decreased considerably and thus the brightness on the
surface of the molded article deteriorated extremely. It is
considered that this is caused by poor dispersibility of the
resins, compared to Example 1.
Examples 6 to 11
[0157] In Examples 6 to 11, components (a), (c) and (d) and
optionally (e) were charged all together into a twin-screw kneader,
kneaded at a kneading temperature of 180 to 240.degree. C. and a
screw rotation speed of 100 rpm and pelletized. The pellets
obtained were put in a predetermined mold and pressed in the
conditions of 220.degree. C. and 50 kg/cm.sup.2 to prepare sheets
for the aforesaid evaluation methods (1) to (6). The results are as
shown in Table 5.
Comparison Examples 11 to 12
[0158] The same procedures were repeated as in the aforesaid
Examples, except that each of the following polyethylenes which had
been polymerized without using a single site catalyst was used in
place of component (c).
[0159] Polyethylene for Comparison Example 11,
[0160] V-0398CN, ex Idemitsu Petrochemical Co.,
[0161] type: HDPE (high density polyethylene)
[0162] density 0.907 g/cm.sup.3
[0163] melt index, determined at 190.degree. C. and a load of 2.16
kg: 3.3 g/10 min.
[0164] Polyethylene for Comparison Example 12,
[0165] 440M, ex Idemitsu Petrochemical Co.,
[0166] type: LLDPE (linear low density polyethylene)
[0167] density: 0.954 g/cm.sup.3
[0168] melt index, determined at 190.degree. C. and a load of 216
kg: 10 g/10 min
[0169] The results are as shown in Table 5.
8 TABLE 5 Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex. 10 Ex. 11 Comp. Ex. 11 Comp.
Ex. 12 Component (a) 100 100 100 100 100 100 100 100 Component (c)
, c-1 100 100 100 130 70 100 100 100 Component (d) 30 45 60 45 45
45 45 45 Component (e) 20 Specific gravity 0.89 0.89 0.89 0.89 0.89
0.92 0.9 0.92 Hardness, 70 77 84 86 87 79 96 50* after HDA 15
seconds Tensile strength, MPa 28 33 38 32 43 30 24 28 Tensile
elongation, % 560 570 590 580 600 530 530 230 Stress at 100%
elongation, MPa 3.5 4 5 4.5 5.4 3.8 2.8 4.2 Impact resilience, % 60
58 55 56 58 54 42 40 Compression set (125.degree. C. .times. 1 hr),
% 44 47 50 61 56 44 80 90 Moldability .circleincircle.
.circleincircle. .circleincircle. .circleincircle. .circleincircle.
.circleincircle. .largecircle. X Residue after evaporation of
n-heptane, ppm 80 80 80 100 60 70 70 70 Residue after evaporation
of water, ppm 0 0 0 0.5 0 0 0 0 Residue after evaporation of 10 10
9 2 9 8 -- -- 20% ethenol, ppm Potassium permanganate, ppm 0.3 0.3
0.2 0.8 0.2 0.3 0.5 1 *represented by D hardness; the others were
represented by A hardness.
Comparison Examples 13 to 17
[0170] The same procedures were repeated as in the aforesaid
Examples, except that components (a), (c), (d) and (e) were used in
an amount exceeding or below the range of the present invention.
The results are as shown in Table 6.
9 TABLE 6 Comp. Ex. 13 Comp. Ex. 14 Comp. Ex. 15 Comp. Ex. 16 Comp.
Ex. 17 Component (a) 100 100 100 100 100 Component (c) , c-1 100
100 3 180 100 Component (d) 3 100 45 45 45 Component (e) 120
Specific gravity 0.89 0.89 0.89 0.89 1.05 Hardness, 65 94 90 79 93
after HDA 15 seconds Tensile strength, MPa 25 35 46 33 4.5 Tensile
elongation, % 630 550 630 600 60 Stress at 100% elongation, MPa 2.5
8.5 7 4 -- Impact resilience, % 55 41 55 58 25 Compression set
(125.degree. C. .times. 1 hr), % 95 92 42 90 -- Moldability X
.largecircle. .largecircle. .largecircle. X Residue after
evaporation of n-heptane, ppm 120 110 80 130 -- Residue after
evaporation of water, ppm 0.6 0.3 0 0.3 -- Residue after
evaporation of 3 2 5 3 -- 20% ethenol, ppm Potassium permanganate,
ppm 0.9 0.3 0.2 0.5 --
* * * * *